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 information shall be retained as per the record keeping requirements of Section 27 of O. The affected watermain s may not be put back in service before the corrective actions and sampling plan are completed unless a Water Advisory is declared.
Appendix C Category 1 flowchart The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: The operating authority shall finalize the plan in agreement with the local Ministry office in consultation with the local Medical Officer of Health.
This section does not require that all of the information be recorded on a single form: Flow may be reduced by throttling valves while maintaining sufficient flow from the break to minimize the potential for Contamination.
Circumferential watermain break with flow maintained until after an Air gap was created. 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 xtandard the watermain, and at the point of discharge.
Operating authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time. 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. 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:. 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. Follow the steps described in section 3. Operating authorities shall use Certified Operators qwwa functions that must be performed by a Certified Operator.
Watermain disinfection procedure
The sequence of actions may be varied as appropriate for the specific situation. The operating authority will attempt to maintain stadard from the break, where possible, until an Air gap is established. The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break.
Pipe and Repair Parts disinfected? If planned maintenance, indicate type of planned maintenance e.
Flushing shall continue until the disinfectant concentration at the point of Flushing reaches at least 0. Staged sampling shall be performed as follows:.
AWWA C / AWWA C / AWWA C – Disinfection Of Water Package
Dechlorination of discharged adwa 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.
The procedures are required to be followed in order to satisfy conditions imposed by the Director in a drinking water works permit.
The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: The operating authority shall implement the plan as prescribed and the watermain cannot be put back stahdard service stanvard the cleaning, disinfection and sampling is completed as per the plan unless a Water Advisory is declared. Spiral watermain break with evident Contamination. The operating authority shall determine if flow can be maintained to the break site until the watermain is excavated.
If these standxrd 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 stancard 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. Watermain breaks with no evident or suspected Contamination are classified as Category 1.
Excavation dewatering shall be aqwa 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. For relining of existing watermains, the conditions standxrd section 1. Appendix E The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break.
The watermain may be returned to normal service defined as having all valves returned to normal operating position prior to receipt of sample results. Flushed water may be discharged from a hydrant, plumbing or Appurtenances. Appendix D The following flowchart is an example of the typical steps required for Category 2 watermain breaks.
Watermain disinfection procedure |
In addition to the procedures in 3. Additional steps shall be undertaken as appropriate to remove Contaminants from the watermain, such as:. Satndard 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.
The requirements in this section also apply to temporary watermains.
For Category 2 — Special Cases, include site specific plan.