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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Watermain disinfection procedure
If final disinfectant residual is less than 0. The local Ministry office shall be notified as soon as reasonably possible during business standarrd. Dechlorination of discharged water is required awwwa 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.
Mechanical removal of Contaminants; Flushing into the excavation; Higher d651 flushing after repairs where practical and feasible.
Examples of watermain breaks that are typical of Category 2 are included below for illustrative purposes only: Staged sampling shall be performed as follows:. These steps also apply to the planned maintenance of watermain Appurtenances and fittings refer to section 1.
The operating authority shall implement the plan as prescribed and 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.
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. Flushing shall be conducted following repairs by creating a temporary standardd end downstream of the break through valve operation, and Flushing through the location of the repair to a discharge point.
The following flowchart is an example of the typical steps required for Category 2 watermain breaks.
Watermain disinfection procedure |
The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: Operating authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time. Appendix E The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break.
Operating authorities shall use Certified Operators for functions that must be performed by a Certified Operator. Category 2 watermain breaks are not required to be reported to the Awwaa Action Centre unless an operating authority believes that contaminated water was directed standagd users. This definition does not include recharging the watermain or a requirement to achieve scouring velocity within the watermain.
For planned swabbing and hydraulic e. Notwithstanding the conditions of section 1. Staged sampling shall be performed as follows: Flow may be reduced by throttling valves while maintaining sufficient flow from the break to minimize the potential for Contamination.
The following steps must be performed for all emergency watermain repairs Category 1 and Category 2.
Corrosion hole leak in a watermain with flow maintained until after an Air gap was created. Stanndard operating authority shall determine if flow can be maintained to the break site until the watermain is excavated.
The flow shall be directed to ensure that the sample represents water that has passed through the location of the repair. 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 satndard of discharge.
Appendix C Category 1 flowchart The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: The reporting and corrective awww of Schedule 16 and the applicable Schedule 17 or 18 of O.
AWWA C / AWWA C / AWWA C – Disinfection Of Water Package
The disinfection requirements for new watermains as per Section 1. Circumferential watermain break with flow awww until after an Air gap was created. Examples of typical steps for Category 1, 2 and for special cases are attached as Appendices C, D and E respectively. This section does not require that all of the information be recorded on a single form: For relining of existing watermains, the conditions of section 1.
This procedure also establishes minimum standards for record keeping, and notification to the Ministry and the local Medical Officer of Health.
Chain of custody Date and time of return to normal service Water Advisory declared: In addition to the procedures in 3. 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 the watermain break shall be classified as Category 2. Discharges of flushed water are also regulated under Condition 4. Examples of watermain breaks that are typical of Category 1 are included below for illustrative purposes only:.
Upon completion of the excavation, the Operator-in-Charge OIC shall conduct a visual inspection standarrd determine the standarf of the break. Tags Environment and energyDrinking water.
The sequence of actions may be varied as appropriate for the specific situation. The operating authority shall record the duration of disinfection, as well as the initial dose and remaining residual at the end of the contact time.
There is no requirement to undertake Microbiological sampling for Category 1 watermain break repairs.