This document is an American Water Works Association (AWWA) standard. It is not a .. This foreword is for information only and is not a part of AWWA C AWWA C Disinfecting Water Mains. Current; Document Language: English; Published By: American Water Works Association (AWWA). AWWA C and these specifications. Disinfection requirements shall include preventive and corrective measures during construction, forms of chlorine and.
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The operating authority will attempt to maintain flow from the break, where possible, until an Air gap is established. Additional steps shall be undertaken as appropriate to remove Contaminants from the watermain, such as:.
If chlorine disinfection was used, indicate initial concentration, contact time, final concentration and final concentration as percentage of initial concentration. Due 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 referred to in section 1.
Watermain disinfection procedure |
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. The following flowchart is an example of the typical awwaa required for Category 2 watermain breaks.
When performing maintenance and repair activities as per sections 1. The sampling plan shall include as a minimum taking two sets of Microbiological samples at least 24 hours apart.
After business hours, the operating authority shall send an e-mail to the e-mail address specified by local Ministry office no later than 10 AM the next business day; or in the Special Cases described in sections 3.
Where there is no discharge point to allow for Flushing, the operating authority shall tap the watermain on the downstream side of the break and discharge from that point.
AWWA C / AWWA C / AWWA C – Disinfection Of Water Package
Appendix B Tools to help determine the category of awwaa break – pictures Examples of watermain breaks that are typical of Category 1 are included aswa for illustrative purposes only: 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.
Circumferential watermain break with flow maintained until after an Air gap was created. Corrosion hole leak in a watermain with flow maintained until after an Air gap was awwq. If there is evident or suspected chemical Contamination of a watermain, in addition to the procedures in sections 3.
For Category 2 — Special Cases, include site specific plan. Notification to the local Ministry office is not required for Category 2 c561 breaks unless:.
Flushing watermain cleaning, the requirements of section 3. Category 1 watermain breaks are not defined as an observation of improper disinfection in accordance with Section of Schedule 16 of O. Operating Authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time.
The watermain may be returned to normal service defined as having all valves returned to normal operating position prior to receipt of sample results. Operating c51 may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time. 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. Disinfectant residual on final post repair Flushing.
This section does not require that all of the information be recorded on a single form: There is no requirement to undertake Microbiological sampling for Category 1 watermain break repairs. Discharges awwa flushed water are also regulated under Condition 4. Appendix E The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break.
Watermain disinfection procedure
For new watermains with limited sampling points available, an alternative method of collecting Microbiological samples is called staged sampling. In addition to the requirements described in section 3. If there is evident or suspected sewage Contamination of a watermain, in addition to the procedures in sections 3.
Watermain repairs involving more than 6 metres of replaced pipe are also classified as Category 2. Dechlorination of discharged water is required for any water that is directed into surface water or if the discharge into the natural environment causes or is likely to cause an adverse effect, as per Condition 10 of Schedule B of the Municipal Drinking Water Licence. aww
c561 Examples of typical steps for Category 1, 2 and for special cases are attached as Appendices C, D and E respectively. 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. Tags Environment and energyDrinking water.
The procedures are required to be followed in order to satisfy conditions imposed by the Director in a drinking water works permit.