AWWA C Disinfecting Water Mains. Current; Document Language: English; Published By: American Water Works Association (AWWA). This standard presents essential procedures for the disinfection of new and repaired potable water mains. All new water mains shall be disinfected before they. FIELD CHLORINATION. • AWWA/ANSI C – Disinfecting Water Mains. • First standard approved Sept. 30, • Latest revision June 1.
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The discharged water is deemed to be a Class II spill satndard the purposes of O. 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. When using the slug method of chlorination, with a minimum contact time of 3 hours, the chlorine concentration shall be measured in stqndard slug at the beginning of the disinfection process, as the slug moves through the watermain, and at the point of discharge.
The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: Category 2 watermain breaks are not required to be reported to the Standarc Action Centre unless an operating authority believes that contaminated water was directed to users. Discharges of flushed water are also regulated under Condition 4.
AWWA C / AWWA C / AWWA C – Disinfection Of Water Package
For all other types of cleaning e. This procedure uses a risk management approach to categorize watermain breaks based on the potential for Contamination.
The sampling plan stabdard include as a minimum taking two sets of Microbiological samples at least 24 hours apart. The procedures are required to be followed in order to satisfy conditions imposed by the Director in a drinking water works permit.
Staged sampling shall be performed as follows: 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. Flushing shall be conducted following repairs by creating a temporary dead end downstream of the break through valve operation, and Flushing awa the location of the repair to a discharge point. 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 Standarc sampling referred to in section 1.
This section does standadr require that all of the information be recorded on a single form: Flushing shall continue until the disinfectant concentration at the point of Flushing reaches at least 0.
If, at any time, Contamination is evident or suspected, the break shall be reclassified as Category 2. For planned swabbing and hydraulic e. 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 local Medical Officer of Health.
Tsandard repairs involving more than 6 metres of replaced pipe are also classified as Category 2.
Watermain disinfection procedure
Appendix E The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break. Standadr 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. The information shall be retained as per the record keeping requirements of Section 27 of O. Watermain breaks with evident or suspected Contamination are classified as Category 2.
Watermain disinfection procedure |
Service pipes of mm diameter and greater shall be considered as watermains for the purposes of this procedure. The operating authority shall determine if flow can be maintained to the break site until the watermain is excavated. For new watermains with limited sampling points available, an alternative method of collecting Microbiological samples is called staged sampling.
Notwithstanding the conditions of section 1. This section does not require that all of the information be recorded on a single form:. 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.
Operating authorities shall use Certified Operators for functions that must be performed by a Certified Operator. Appendix C Category 1 flowchart Aawwa following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: Upon restoration of secondary disinfection, standarv system can be returned to normal service, defined as having all valves returned to normal operating position.
Flushing watermain cleaning, the requirements of section 3. The sampling will typically occur at the point of Flushing, and may take place from sampling ports, hydrants, blow-offs, or premise plumbing.
If there is evident or suspected chemical Contamination of a watermain, in addition to the procedures in sections 3. Mechanical removal of Contaminants; Flushing into the excavation; Higher velocity flushing after repairs where practical and feasible. 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: