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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Flushed water may be discharged from a hydrant, plumbing or Appurtenances. The sequence of actions may be varied as appropriate for the specific situation. Mechanical removal of Contaminants; Flushing into the excavation; Higher velocity flushing after repairs where practical and feasible. 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.
The operating authority shall determine if flow can be maintained to the break site until the watermain is excavated. This procedure uses a risk management approach to categorize watermain breaks based on the potential for Contamination. Watermain breaks with evident or suspected Contamination are classified as Category 2. If planned maintenance, indicate type of planned maintenance e.
Service pipes of mm diameter and greater shall be considered as watermains for the purposes of this procedure. The following flowchart is an example of the typical steps required for Category 2 watermain breaks.
These steps also apply to the planned maintenance of watermain Appurtenances and fittings refer to section 1.
Skip to main content. Watermain repairs involving more than 6 metres of replaced pipe are also classified as Category 2.
The disinfection requirements for new watermains as per Section 1. Notification to the local Ministry office is not required for Category 2 watermain breaks unless:. 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.
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.
Due to the chlorine demand exerted by the copper, no minimum chlorine concentration is required following the 24 hour contact time, and the effectiveness of the disinfection process shall be demonstrated by the Microbiological sampling referred to in section 1. Flushing shall continue until the disinfectant concentration at the point of Flushing reaches at least 0.
Operating Authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time. Flushing shall continue until the discharged water is free from discoloration, and secondary disinfection has been restored as per 3. If, at any time, Contamination is evident or suspected, the break shall be reclassified as Category 2.
For Category 2 — Special Zwwa, include site specific plan. If an operating authority believes that wwwa water was directed to users, this will constitute an observation of improper disinfection in accordance with Section of Schedule 16 of O. Corrosion hole leak in a watermain with flow maintained until after an Air gap was created.
For all other types of cleaning e. 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 x651 in this awws also apply to temporary watermains.
Watermain disinfection procedure
In developing these procedures, operating authorities may use best management practices that go beyond the minimum requirements in this document. Operating authorities shall develop and document operating procedures for emergency watermain repairs within their systems.
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. Pipe aswa Repair Parts disinfected?
AWWA C / AWWA C / AWWA C – Disinfection Of Water Package
The watermain may be returned to normal service defined as having all valves returned to normal operating position prior to receipt of sample results. Appendix E The following flowchart depicts the requirements for special case Contamination sewage or chemical as a result of a watermain break. 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.
The sampling will typically occur at the point of Flushing, and may take place from sampling ports, hydrants, blow-offs, or premise plumbing. Examples of typical steps for Category 1, 2 and for special cases are attached as Appendices C, D and E respectively. Chain of custody Date and time of return to normal service Water Advisory declared: The operating authority will attempt to maintain flow from the break, where possible, until an Air gap is established.
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. Operating authorities may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time. Notification to the local Ministry office is not required for Category 2 watermain breaks unless: When performing maintenance and repair activities as per sections 1.
Watermain disinfection procedure |
Examples aww watermain breaks that are typical of Category 2 are included below for illustrative purposes only:. The information shall be retained as per the record keeping requirements of Section 27 of O. 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 reporting and corrective actions of Schedule 16 and the applicable Schedule 17 or 18 of O.
In addition to the requirements described in section 3.