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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Chain of custody Date and time of return to normal service Water Advisory declared: The reporting and corrective actions of Schedule 16 and c6511 applicable Schedule 17 or 18 of O. Watermain breaks with no evident or suspected Contamination are classified as Category 1.
Watermain disinfection procedure |
Flushed water may be discharged from a hydrant, plumbing or Appurtenances. Follow the steps described in section 3. Service pipes of mm diameter and greater shall be considered as watermains for the purposes aawa this procedure. There is no requirement to undertake Microbiological sampling for Category 1 watermain break repairs.
The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break.
Watermain disinfection procedure
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.
The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: Examples of watermain breaks that are typical of Category 1 are included below for illustrative purposes only:.
If planned maintenance, indicate type of planned maintenance e.
Upon restoration of secondary disinfection, the system can be returned to normal service, defined as having all valves returned to normal operating position.
Pipe and Repair Parts disinfected? The operating authority shall finalize the plan in agreement with awsa local Ministry office in consultation with the local Medical Officer of Health.
Upon completion of the excavation, the Operator-in-Charge OIC shall conduct a visual inspection to determine the nature of the break. Return awwa 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.
The local Ministry office shall be notified as soon as reasonably possible during business hours. 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 through the watermain, and at the point of discharge.
After business hours, the operating authority shall contact v651 Spills Action Centre as soon as reasonably possible. Examples of watermain breaks that are typical of Category 2 are included below for illustrative purposes only: If there is evident or suspected chemical Contamination of a watermain, in addition to the procedures in sections 3.
Share facebook twitter Print. 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 c561.
AWWA C / AWWA C / AWWA C – Disinfection Of Water Package
The discharged water is deemed to be a Class II spill for the awsa of O. Operating authorities shall use Certified Operators for functions that must be performed by a Certified Operator.
Flushing shall continue until the discharged water is free from discoloration, and secondary disinfection has been restored as per 3. Mechanical removal of Contaminants; Flushing into the excavation; Higher velocity flushing after repairs where practical and feasible. Watermain repairs involving more than 6 metres of replaced pipe are also classified as Category 2.
The procedures are required to be followed in order to satisfy conditions imposed by the Director in a drinking water works permit. D651 disinfection requirements for new watermains as per Section 1. 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.
Flow may be reduced by throttling valves while maintaining sufficient flow from the break to minimize the potential for Awa. The OIC will assess the evidence of Contamination or potential Contamination of the watermain before and during the repair procedure, and shall classify the break into one of two categories as per 3.
Staged sampling shall be performed as follows:. Spiral watermain break with evident Contamination. 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: Drinking water 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.
Operating authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time. The operating authority shall determine if flow can be maintained to the break site until the watermain is excavated. The sampling will typically occur at the point of Flushing, and may take place from sampling 6c51, hydrants, awaa, or premise plumbing. X651 there is evident or suspected sewage Contamination of a xwwa, in addition to the procedures in sections 3.
If chlorine disinfection was used, indicate initial concentration, contact time, final concentration and final concentration as percentage of initial concentration.
This section does not require that all of the information be recorded on a single form: The flow shall be directed to ensure that the sample represents water that has passed through the location of the repair.