Disinfecting Tank Methods

Question 1

(a) Fill tank to over flow level
(b) Add chlorine to achieve 10ppm FAC through the tank
1) Hold solution for 24 hours
(c) Drain tank
(d) Refill tank with potable water with required halogen residual level
(e) Perform bacteriological testing
1) If test comes back negative use water

Answer 1

Method 1

Question 2

(a) Spray/apply directly 200ppm FAC to all tank surfaces
(b) Flush inlet/outlet pipes with 10ppm FAC
(c) Disinfected surfaces shall remain in contact with chlorine solution for a
minimum of 30 minutes
(d) Refill tank with potable water with required halogen residual level
(e) Perform bacteriological testing
1) If test comes back negative use water

Answer 2

Method 2

Question 3

(a) Fill 5% of tank volume with 50ppm FAC Solution
(b) Hold solution for 6 hours
(c) Add potable water to chlorine solution to fill tank; hold this water for 24 hours
(d) Drain tank
(e) Refill tank with potable water with required halogen residual level
(f) Perform bacteriological testing
1) If test comes back negative use water

Answer 3

Method 3