This document is an American Water Works Association (AWWA) standard. It is not a specification. AWWA standards describe minimum requirements and do not . This standard describes essential procedures for the disinfection of new and repaired potable water mains. New water mains shall be disinfected before they ar. AWWA/ANSI C – Disinfecting Water Mains *It is recommended that you follow the current AWWA C specification with the following.
|Published (Last):||24 March 2011|
|PDF File Size:||8.18 Mb|
|ePub File Size:||18.29 Mb|
|Price:||Free* [*Free Regsitration Required]|
Appendix C Category 1 flowchart The disinfceting flowchart is an example of the typical steps required for Category 1 watermain breaks Note: For planned swabbing and hydraulic e. 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.
Operating authorities shall develop mzins document operating procedures for emergency watermain repairs within their systems.
AWWA C Disinfecting Water Mains | – BNI Books
If there is evident or suspected chemical Contamination of a watermain, in addition to the procedures in sections 3. After business hours, the operating authority shall contact the Spills Action Centre as soon as reasonably possible. Notification to the local Ministry office is not required for Category 2 watermain breaks unless: Examples of watermain breaks that are typical of Category 2 are included below for illustrative purposes only: If, at any time, Contamination is evident or suspected, the break shall be reclassified as Category 2.
All samples shall be considered distribution samples, taken and tested in accordance with O. For Category 2 — Special Cases, include site specific plan.
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.
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.
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. Appendix B Tools to help determine the category of watermain break – pictures Examples of awwz breaks that are typical of Category 1 are included below for illustrative purposes only: 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.
Operating authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time.
Watermain disinfection procedure |
The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: Example 3 When using the slug method of chlorination, with a disimfecting 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 disinfectijg, and at the point of discharge. Where the operating authority opts to undertake Microbiological sampling, samples shall be considered distribution samples within the meaning of O.
The reporting and corrective actions of Schedule 16 and the applicable Schedule 17 or 18 of O. Flushed water may be discharged from a hydrant, plumbing or Appurtenances. Examples of watermain breaks that are typical of Category 2 are included below for illustrative purposes only:. Operating Authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time.
With respect to disinfectin watermains, relined watermains and temporary watermains, the provisions of this document, including sections disinfectign. The procedures are required to be aawa in order to satisfy conditions imposed by the Director in a drinking water works permit. After business hours, the operating authority shall send an e-mail to the e-mail address specified by local Ministry office no later than 10 AM the next business day; or in the Special Cases described in sections 3.
Watermain breaks with no evident or suspected Contamination are classified as Category 1.
Staged sampling shall be performed as follows: If planned maintenance, indicate type of planned maintenance e. After the completion of Flushing and restoration of secondary disinfection, at least one Microbiological sample shall be collected and submitted as soon as reasonably possible, taking into consideration laboratory working hours and transportation timeframes. 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. Category 2 watermain breaks are not required to be reported to the Spills Action Centre unless an operating authority believes that contaminated water was directed to users.
The local Ministry office shall be notified as soon as reasonably possible during business hours. The following flowchart is an example of the typical steps required for Category 2 watermain breaks.
AWWA C651-05: Disinfecting Water Mains
These diisnfecting also apply to the planned maintenance of watermain Appurtenances and fittings refer to section 1. Flushing shall continue until the disinfectant concentration at the point of Flushing reaches at least 0.
Watermain breaks with evident or suspected Contamination are classified as Category 2. Category 1 watermain breaks are fisinfecting defined as an observation of improper disinfection in accordance with Section of Schedule 16 of O.
The operating authority shall awwz 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. If Contamination is evident or suspected, the procedures defined under section 3 for Category 2 watermain breaks shall apply.
Service pipes of mm diameter and greater shall be considered as watermains for the purposes of this procedure. If final disinfectant residual is less than 0. Mechanical removal of Contaminants; Flushing into the excavation; Higher velocity flushing after repairs where practical and feasible. Appendix D The following flowchart is an example of the typical steps required for Category disinfectkng watermain breaks.
Watermain disinfection procedure
Circumferential watermain break with flow maintained until after an Air gap was created. Corrosion hole leak in a watermain with flow maintained until after an Air gap was created. Chain of custody Date and time of return to normal service Water Advisory declared: