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
Flow may be discontinued after an Air gap has been created. 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.
The requirements in this section also apply to temporary watermains. If Contamination is xwwa or suspected, the procedures defined under section 3 for Category 2 watermain breaks shall apply. The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break.
Operating Authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time. Notwithstanding the conditions of section 1. Flushing shall continue until the disinfectant concentration at the point of Flushing reaches at least 0.
Appendix C Category 1 flowchart The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: Chlorine Concentrations and Contact Times for New Watermains At levels over 10 milligrams per litre, a measurement of total chlorine shall be deemed to stanrard equivalent to a measurement of free chlorine.
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. If, at any time, Contamination is evident or suspected, the break shall be reclassified as Category 2. Examples of watermain breaks that are typical of Category 2 are included below for illustrative purposes only: Corrosion hole leak in a watermain with flow maintained until after an Air gap was created.
Category 2 watermain breaks are not required to be reported to the Spills Action Centre unless an awwq authority believes that contaminated water was directed to users. The following flowchart is an example of the typical steps required for Category 2 watermain breaks. With respect to new watermains, relined watermains and temporary watermains, the provisions of this document, including sections 1.
Examples of typical steps for Stanxard 1, 2 and for special cases are attached as Appendices C, D and E respectively. Appendix D The following flowchart is an example of the typical steps required for Category 2 watermain breaks. Pipe and Repair Parts disinfected?
AWWA C / AWWA C / AWWA C – Disinfection Of Water Package
If these disinfectant concentrations cannot be achieved, Flushing shall continue until the disinfectant concentration at the point of Flushing is representative of the system residual in the break area, determined by sampling upstream of the break area and downstream at the Flushing location, or by using documented benchmarks for the area, as long as free chlorine concentrations are at least 0. Drinking stajdard system operating authorities shall ensure that emergency repairs to watermains and Appurtenances are undertaken in accordance with this procedure by any person authorized to perform the repairs.
In developing these procedures, operating authorities may use best stndard practices that go beyond the minimum requirements in this document. All samples shall be considered distribution samples, taken and tested in accordance with O. Service pipes of standardd diameter and greater shall be considered as watermains for the purposes of this procedure.
Flushing watermain cleaning, the requirements of section 3. For Category 2 — Special Cases, include site specific plan.
For relining of existing watermains, the conditions of section 1. Examples of watermain breaks that are typical of Category 1 are included below for illustrative purposes only:. Appendix E The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break.
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.
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. Flushed water may be discharged from a hydrant, plumbing or Appurtenances. This document outlines procedures for disinfecting water mains as part of an addition, modification, replacement, extension, planned maintenance, or emergency repair in a municipal residential drinking water system. Discharges of flushed water are also regulated under Condition 4.
Operating authorities shall use Certified Operators for functions that must be performed by a Certified Operator. The operating authority shall finalize the plan in agreement with the local Ministry office in consultation with the local Medical Officer of Health.
The following flowchart is an example of the typical steps required for Category x651 watermain breaks Note: Chain of custody Date and time of return to normal service Water Advisory declared: 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 stanadrd, and at the point d651 discharge.
After business hours, the operating authority shall contact the Spills C65 Centre as soon as reasonably possible. Flow may be reduced by throttling valves while maintaining sufficient flow from the break to minimize the potential for Contamination. This definition does not include recharging the watermain or a requirement to achieve scouring velocity within the watermain.
If planned maintenance, indicate type of planned maintenance e. Longitudinal watermain break with evident Contamination. This section does not require that all of the information be recorded on a single form:.
Refer to Appendices A and B for a flowchart and pictures to better understand the criteria to determine the categories of watermain breaks. Share facebook twitter Print.