|RESERVOIR CLEANING, DISINFECTION, TESTING
Cleaning – M.B.S.I. will clean and pressure wash the interior of the reservoir after it is constructed.
Disinfecting – M.B.S.I. recommends Method 2 per AWWA C652-86. (See Below) This method is recommended because it does not require disposal or neutralization of large amounts heavily chlorinated water which can be hazardous to the environment.
Testing (Reservoir) – Testing of the reservoir consists of filling the reservoir to check for water tightness. M.B.S.I. recommends that this be done no sooner that 28 days after all concrete pouring is completed and no later than 60 days after completed. This need not be a separate “leak” test as called for by some engineers, but can be the initial filling after the reservoir is disinfected. The testing of the water can be done from this initial filling and if there are no obvious problems with the reservoir, it can be put on line without emptying and refilling.
To test the reservoir, fill to full, close all valves and let set for 24 hours. Note the height of the water. Check the water height after 3 consecutive 24 hour periods. Allowing for evaporation, the water level shouldn’t drop more that 1 tenth of one percent in any 24 hour period.
Testing (Water) – Testing the water to make sure it is safe for drinking typically consists of taking samples of the water to a certified lab for bacterial testing prior to placing the reservoir in service. Special attention must be given to ensure that the water source has been tested and is clear of bacteria and contaminants.
Chlorination, AWWA C652-86 – Method 2 – full text:
A solution of 200 mg/L available chlorine shall be applied directly to the surfaces of all parts of the storage facility which would be in contact with water when the storage facility is full to the overflow elevation..
Method of application: The chlorine solution may be applied with suitable brushes or spray equipment. The solution shall thoroughly coat all surfaces to be treated, including the inlet and outlet piping, and shall be applied to any separate drain piping such that it will have available chlorine of not less than 10 mg/L when filled with water. Overflow piping need not be disinfected.
Retention: The surfaces disinfected shall remain in contact with the strong chlorine solution for at least 30 minutes after which potable water shall be admitted, the drain piping shall be purged of the 10 mg/L chlorinated water, and the storage facility shall then be filled to its overflow level. Then, subject to satisfactory bacteriological testing, acceptable aesthetic quality, such water may be served to the distribution system.