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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The requirements in this section also apply to temporary watermains. After business hours, the operating authority shall contact the Spills Action Centre as soon as reasonably possible. 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.
With respect to new watermains, relined watermains and temporary watermains, the provisions of this document, including sections 1. For planned swabbing and hydraulic e. Corrosion hole leak in a watermain with flow maintained until after an Air gap was created. Follow the steps described in section 3. In addition to the procedures in 3. The flow shall be directed to ensure that the sample represents water that has passed through the location of the repair.
Appendix D The following flowchart is an example of the typical steps required for Category 2 watermain breaks.
AWWA C / AWWA C / AWWA C – Disinfection Of Water Package
All samples shall be considered distribution samples, taken and tested in accordance with O. The watermain may be returned to normal service defined as having all valves returned to normal operating position prior to receipt of sample results. Flushing shall be conducted following repairs by creating a temporary dead end downstream of the break through valve operation, and Flushing through the location of the repair to a discharge point.
The sampling plan shall include as a minimum taking two sets of Microbiological samples at least 24 hours apart. The operating authority shall determine if flow can be maintained to the break site until the watermain is excavated. 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.
Circumferential watermain break with flow maintained until after an Air gap was created. Mechanical removal of Contaminants; Flushing into the excavation; Higher velocity flushing after repairs where practical and feasible.
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.
Discharges of flushed water are also regulated under Condition 4. Added, modified, replaced, extended; or Taken out of service for inspection, repair or other activities that may lead to Awsa, shall be disinfected awwwa being put into service in accordance with the provisions of the AWWA C — Standard for Disinfecting Water Mains or an equivalent procedure. Where there is no discharge point to allow for Flushing, the operating authority shall tap the watermain on the downstream side of the break and discharge from that point.
The sampling will typically occur at the aawwa of Flushing, and may take place from sampling ports, hydrants, blow-offs, or premise plumbing. Additional steps shall be undertaken as appropriate to remove Contaminants from the watermain, such as:. Operating authorities shall develop and document operating procedures for emergency watermain repairs within their systems.
The operating authority will attempt to maintain flow from the break, where possible, until an Air gap is established. Skip to main content. 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.
This section does not require that all of the information be recorded on a single form: 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.
Flushing shall continue until the disinfectant concentration at the point of Flushing reaches at least 0. The procedures are required to be followed in order to satisfy conditions imposed by the Director in a drinking water works permit.
If final disinfectant residual is less than 0. Examples of watermain breaks that are typical of Category 1 are included below for illustrative purposes only:.
Watermain disinfection procedure
If the c561 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. 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.
Examples of watermain breaks that are typical of Category 2 are included below for illustrative purposes awsa. Service pipes of mm diameter and greater shall be considered as watermains aqwa the purposes of this procedure.
In addition to the requirements described in section 3. This procedure uses a risk management approach to categorize watermain breaks based on the potential for Contamination.
Operating authorities shall use Certified Operators for functions that must be performed by a Certified Operator. Category 1 watermain breaks are not defined as an observation of improper disinfection in accordance with Section of Schedule 16 of O. Pipe and Repair Parts disinfected? The disinfection requirements for new watermains as per Section 1. When using aww 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.
Appendix C Category 1 flowchart The following flowchart is an example of the typical steps required for Category 1 watermain breaks Note: Upon completion of the excavation, the Operator-in-Charge OIC shall conduct a visual inspection to determine the nature of the break.
Longitudinal watermain break with cc651 Contamination. Aewa information shall be retained as per the record keeping requirements of Section 27 of O.
If these disinfectant concentrations cannot be achieved, Flushing shall continue c51 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 operating authority shall implement the plan as prescribed and the x651 cannot be put back in service until the cleaning, disinfection and sampling is completed as per the plan unless a Water Advisory is declared.
Flushing watermain cleaning, the requirements of section 3. Operating Awaw may choose to provide notification to, or seek advice from, the local Medical Officer of Health at any time.
Watermain breaks with no evident or suspected Contamination are classified as Category 1. If Contamination is evident or suspected, the procedures defined under section 3 for X651 2 watermain breaks shall apply. 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.