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.
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Refer to Appendices A and B for a flowchart and pictures to better understand the criteria to determine the categories of watermain breaks. 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. Examples of watermain breaks that are typical of Category 1 are included below for illustrative purposes only:.
Appendix D The following flowchart is wayer example of the typical steps required for Category 2 watermain breaks. If these awwz concentrations cannot be achieved, Flushing shall continue until the disinfectant concentration at the point of Flushing is representative of the system residual in the break area, determined by disincecting upstream of the break area and downstream at the Flushing location, or by using documented benchmarks for the area, as long as wter chlorine concentrations are at least 0.
The following flowchart is an example of the typical steps required for Category 2 watermain breaks. Appendix E The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break.
If an operating authority believes that contaminated water was directed to users, this will constitute an observation of improper disinfection in accordance with Section of Schedule 16 of O.
Watermain disinfection procedure |
Notwithstanding the conditions of section 1. Added, modified, replaced, extended; awaa 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.
The information shall be retained as per the record keeping requirements of Section 27 of O. Examples of watermain breaks that are typical of Category 2 are included below for illustrative purposes only:.
AWWA C651-05: Disinfecting Water Mains
This procedure also establishes minimum standards for record keeping, and notification to the Ministry and the local Medical Officer of Health. Disinfectiny to the chlorine demand exerted by the copper, no minimum chlorine concentration is required following the 24 hour contact time, and the effectiveness of the disinfection process shall be demonstrated by the Microbiological sampling waetr to in section 1.
Flushing shall be conducted following repairs by creating a temporary dead end downstream of the break through valve operation, and Flushing through the location of the repair to a discharge point. The disinfection requirements for new watermains as per Section 1. Skip to main content. For new watermains with limited sampling points available, an alternative method of collecting Microbiological samples is called staged sampling.
If the water level in the excavation rises such that the Air gap is not maintained after flow from the break has been discontinued, then wwter watermain break shall be classified as Category 2. 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. Flow may be reduced by throttling valves while maintaining sufficient flow from the break to minimize the potential for Contamination.
Operating authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time.
Staged sampling shall be performed as follows:. If, at any time, Contamination is evident or suspected, the break shall be reclassified as Category 2. Follow the steps described in section 3.
AWWA C Disinfecting Water Mains | – BNI Books
Staged sampling shall be performed as follows: If final disinfectant residual is less than 0. Watermain repairs disinfecying more than 6 metres of replaced pipe are also classified as Category 2. Appendix B Tools to help determine the category of watermain break – pictures Examples of watermain breaks that are typical of Category 1 are included below for illustrative purposes only: Operating Authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time.
Appendix C Category 1 flowchart The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: The operating authority will attempt to maintain flow from the break, where possible, until an Air gap is established.
After business hours, the operating authority shall contact the Spills Action Centre as soon as reasonably possible. Disinfectant residual wster final post repair Flushing. Chain of custody Date and time of return to normal service Water Advisory declared: For all other types of cleaning e. This procedure uses a risk management approach to categorize watermain breaks based on the potential for Contamination.
Examples of watermain breaks that are typical of Category 2 are included below for f651-05 purposes only: 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.
Flushing shall continue until the disinfectant concentration at the point of Flushing reaches at least 0. The operating authority shall implement the plan as prescribed diwinfecting the watermain cannot be put back in service until the cleaning, disinfection and sampling is completed as per the plan unless a Water Advisory is declared.
Upon completion of the excavation, the Operator-in-Charge OIC shall conduct a visual inspection to determine the nature of the break. If chlorine disinfection was used, indicate initial concentration, contact time, final concentration and final concentration disifecting percentage of initial concentration. The following steps must be performed disinfcting all emergency watermain repairs Category 1 and Category 2.