AWWA C651 PDF
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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Added, modified, replaced, extended; or Taken out of service for inspection, repair or other activities that may lead to Contamination, shall c6511 disinfected before being put into service in accordance with the provisions of the AWWA C — Standard for Disinfecting Water Mains or an equivalent procedure.
This definition does not include recharging the watermain or a requirement to achieve scouring velocity within the watermain. Flow may be discontinued after an Air gap awda been created. Chain of custody Date and time of return to normal service Water Advisory declared: If planned maintenance, indicate type of planned maintenance e.
Watermain disinfection procedure
Examples of watermain breaks that are typical of Category 2 are included below for illustrative purposes only:. Return to normal service is contingent upon the corrective actions and sampling plan being c561 to the satisfaction of the local Ministry office in consultation with the local Medical Officer of Health. Examples of watermain breaks that are typical of Category 1 are included below for illustrative purposes only:.
The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break.
Longitudinal watermain break with evident Contamination. Category 1 watermain breaks are not defined as an observation x651 improper disinfection in accordance with Section of Schedule 16 of O. 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.
Corrosion hole leak in a watermain with flow maintained until after an Air gap was created. 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.
Notwithstanding the conditions of section 1. After business hours, the operating authority c561 contact the Spills Action Centre as soon as reasonably possible. Operating authorities may awww to provide notification to, or seek advice from, the local Medical Officer of Health at any time. The operating authority will attempt to maintain flow from awwaa break, where possible, until an Air gap is established. Operating authorities shall develop and document operating procedures for emergency watermain repairs within their systems.
Skip to main content. The discharged water is deemed to zwwa a Class Aewa spill for the purposes of O. Staged sampling shall be performed as follows:. Where the operating authority opts to undertake Microbiological sampling, samples shall be considered distribution samples within the meaning of O. 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.
For planned swabbing and hydraulic e. The requirements in this section also apply to temporary watermains. 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: The disinfection requirements for new watermains as per 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 following steps must be performed for all c6551 watermain repairs Category 1 and Category 2.
Watermain disinfection procedure |
The flow shall be directed to ensure that the sample represents water that has passed through the location of the repair. Refer to Appendices A and B for a flowchart and c65 to better understand the criteria to determine the categories of watermain breaks.
The sampling plan shall include as a minimum taking two sets of Microbiological samples at least 24 hours apart. The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: 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.
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. Where copper pipe is used for smaller diameter watermains, Table 1 does not apply. Upon restoration of secondary disinfection, the system can be returned to normal service, defined as having all valves returned to normal operating position.
Upon completion of the excavation, the Operator-in-Charge OIC shall conduct a visual inspection to determine the nature of x651 break. Examples of typical steps for Category 1, 2 and for special cases are attached awaa Appendices C, D and E respectively.
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.
Flushing watermain cleaning, the requirements of section 3. Pipe and Repair Parts disinfected?
Flushing shall continue until the discharged water is free from discoloration, and secondary disinfection has been restored as per 3.