This document is an American Water Works Association (AWWA) standard. It is not a specification. AWWA standards describe minimum requirements and do not . This standard describes essential procedures for the disinfection of new and repaired potable water mains. New water mains shall be disinfected before they ar. AWWA/ANSI C – Disinfecting Water Mains *It is recommended that you follow the current AWWA C specification with the following.
|Published (Last):||7 May 2007|
|PDF File Size:||15.19 Mb|
|ePub File Size:||17.97 Mb|
|Price:||Free* [*Free Regsitration Required]|
The following flowchart is an example of the typical steps swwa for Category 2 watermain breaks. Examples of typical dissinfecting for Category 1, 2 and for special cases are awsa as Appendices C, D and E respectively. The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: Contamination is typically not suspected for circumferential breaks or small leaks where flow is maintained from the break until an Air gap is established and where the Air gap is maintained during the repair procedure.
For relining of existing watermains, the conditions of section 1. These steps also apply to the planned maintenance disiinfecting watermain Appurtenances and fittings refer to section 1. If final disinfectant residual is less than 0. Excavation dewatering shall be continued for the duration of the repairs such that the Air gap between the location of the break in the watermain and the water in the excavation is maintained. Chain of custody Date and time of return to normal service Water Advisory declared: If chlorine disinfection was used, indicate initial concentration, contact time, final concentration and final concentration as percentage of wated concentration.
Appendix E The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break. The affected watermain s may not be put back in service before the corrective actions and sampling plan are completed unless a Water Advisory is declared.
Watermain disinfection procedure |
Watermain breaks with no evident or suspected Contamination are classified as Category 1. Staged sampling shall be performed as follows:. Where copper pipe is used for smaller diameter watermains, Table 1 does not apply.
Skip to main content. When using the slug method of chlorination, with a minimum contact time of 3 hours, the chlorine concentration shall be measured in the slug at the beginning of the disinfection process, as the slug moves through the watermain, and at the point of discharge.
If, at any time, Contamination is evident or suspected, the break shall be reclassified as Category 2. The OIC will assess the evidence of Contamination or potential Contamination of the watermain before and during the repair procedure, and shall classify the break into one of two categories as per 3.
The flow shall be directed to ensure that the sample represents water that has passed through the location of the repair. Appendix C Category 1 flowchart The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: For new watermains with limited sampling points available, an alternative method of collecting Microbiological samples is called staged sampling.
Upon completion of the excavation, the Operator-in-Charge OIC shall conduct a visual inspection to determine the nature of the break.
AWWA C Disinfecting Water Mains | – BNI Books
Operating authorities shall develop and document operating procedures for emergency watermain repairs within their systems. Pipe and Repair Parts disinfected? The disinfection requirements for new watermains as per Section 1. Return to normal service is contingent upon the corrective actions and sampling plan being completed to the satisfaction of the local Ministry office in consultation with the local Medical Officer of Health.
The operating authority shall determine if flow can be maintained to the break site until the watermain is excavated. If there is evident or suspected chemical Contamination of a watermain, in addition to the procedures in sections 3. Category 2 watermain breaks are not required to be reported to the Spills Action Centre unless an operating authority believes that contaminated water was directed to users. After the completion of Flushing and restoration of secondary disinfection, at least one Microbiological sample shall be collected and submitted as soon as reasonably possible, taking into consideration laboratory working hours and transportation timeframes.
Operating Authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any c65-05. With respect to new watermains, relined watermains and temporary watermains, the provisions of this document, including sections 1. This section does not require that all of the information be recorded on a single form: If there is evident or suspected sewage Contamination of a watermain, in addition to the procedures in c651–05 3. Added, modified, replaced, extended; or Taken out of service for inspection, repair or other activities that may lead to Contamination, shall be disinfected before being put into service in accordance with the provisions of the AWWA C — Standard for Disinfecting Water Mains or an equivalent procedure.
Longitudinal watermain break with evident Contamination. There is no requirement to undertake Microbiological sampling for Category disinfectig watermain break repairs. If Contamination is evident or suspected, the procedures defined under section 3 for Category 2 watermain breaks shall apply.
Where the operating authority opts to undertake Microbiological sampling, dissinfecting shall be considered distribution samples within the meaning of O. Due to the chlorine demand exerted by the copper, no minimum chlorine concentration disinfectinf required following disinnfecting 24 hour contact time, and the effectiveness of the disinfection process shall be demonstrated by the Microbiological sampling referred to in section 1.
Watermain disinfection procedure
Refer to Appendices A and B for a flowchart and pictures to better understand the criteria to determine the categories of watermain breaks. Notwithstanding the conditions of section 1. Drinking water system operating authorities shall ensure that emergency repairs to watermains and Appurtenances are undertaken in accordance with this procedure by any person authorized to perform the repairs.
Flushed water may be discharged from a hydrant, plumbing or Appurtenances. Examples of watermain breaks that are typical of Category 2 are included below for illustrative purposes only: The operating authority will attempt to maintain flow from the break, where possible, until an Air gap is established.
Flushing watermain cleaning, the requirements of section 3. The information shall be retained as per the record keeping requirements of Section 27 of O.