Following the pigging process the main was refilled with super chlorinated water for 24 hours and flushed. The chlorine demand on the main dropped significantly. The pigging process was complete with no failures or problems.
The Issue
Toowoomba Regional Council recently had biological growth in a trunk main causing high chlorine demand on the water within the main. Flushing and scouring valves and super chlorinating the main had failed to remove the problem. The Council had no experience in pigging mains.
The Solution
The Council contacted Clearflow for advice and a site inspection was arranged. Clearflow examined the as-constructed drawings and provided advice on where and how to launch and retrieve the pig. The Clearflow crew, in collaboration with Toowoomba Regional Council staff, isolated, drained and cut the main, to insert the pig. A total of 6km of 200mm water main was cleaned in just over one hour, removing the biological build up from the inside surface of the pipe.
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