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 requirements in this section also apply to temporary watermains. Chlorine Concentrations and Contact Times for New Watermains At levels over 10 milligrams per litre, a measurement of total chlorine shall be deemed to be equivalent to a measurement of free chlorine.
The disinfection requirements for new watermains as per Section 1. 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 flow shall be directed to f651 that the sample represents water that has passed through the location of the repair.
Refer to Appendices A and B for a flowchart and pictures to better understand the criteria c51 determine c65 categories of watermain breaks.
Staged sampling shall be performed as follows:. 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.
Spiral watermain break with evident Contamination. Notification to the local Ministry office is not required for Category 2 watermain breaks unless:.
If there is evident or suspected chemical Contamination of a watermain, in addition x651 the procedures in sections 3. Added, modified, replaced, extended; or Taken c6551 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. Upon completion of the excavation, the Operator-in-Charge OIC shall conduct a visual inspection to determine the nature of the break.
Appendix E The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break. For relining of existing watermains, the conditions of section 1. In addition to the requirements described in section 3. If planned maintenance, indicate type of planned maintenance e.
If chlorine disinfection was used, indicate initial concentration, contact time, final concentration and final concentration as percentage of initial concentration. Staged sampling shall be performed as follows: Tags Environment and energyDrinking water.
Operating authorities shall use Certified Operators for functions that must be performed by a Certified Operator. Flushing shall be conducted following repairs wwwa creating a temporary dead end downstream of the break through valve operation, and Flushing through the location of the repair to a discharge point.
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. In addition to the procedures awwq 3. This procedure also establishes minimum standards for record keeping, and notification to the Ministry and the local Medical Officer of Health.
These steps also apply to the planned maintenance of watermain Appurtenances and fittings refer to section 1. The watermain may be returned c6551 normal service defined as having all valves returned to normal operating position prior to receipt of sample results.
Watermain disinfection procedure |
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.
Watermain breaks with evident or suspected Contamination are classified as Category 2. Awda the operating authority opts to undertake Microbiological sampling, samples shall be considered distribution samples within the meaning of O.
Example 3 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.
Contamination is awsa 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. Notwithstanding the conditions of section 1.
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 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. For Category 2 — Special Cases, include site specific plan. The reporting and corrective actions of Schedule 16 and the applicable Schedule 17 or 18 of O.
Flushing shall continue until the disinfectant concentration at the point of Flushing reaches at least 0. Flushing shall continue until the discharged water is free from discoloration, and secondary disinfection has been restored as per 3.
If final disinfectant residual is less than 0. Flushed water may be discharged from a hydrant, plumbing or Appurtenances.
Watermain disinfection procedure
There is no requirement to undertake Microbiological sampling for Category 1 watermain break repairs. This procedure f651 a risk management approach to categorize watermain breaks based on the potential for Contamination. When performing maintenance and repair activities as per sections 1.
For planned swabbing and hydraulic e.