Water cleaning project cold as ice

A multimillion pound initiative by UK, Operation Clean and Clear was started to modernize an ageing water system in Bristol Water and Wessex Water using an innovative ice pigging process. Ice pigging involves cleaning by injecting ice slush into a rising main before forcing it through the pipe with water. A soft plug was formed and pushed along, scouring the main effectively and adapting its shape to navigate through complex pipe work with ease. Samples of slush were taken at the exit point and analyzed. The method involved nine tons of slush being used during the two day trial. During the trial the first pass created a large volume of sludge that was flushed away through the extraction hydrant and removed by tankers. Over the next series of passes there was a dramatic pass the ice plug was clean at extraction point. By using ice pigs there is no need to install multiple chambers and pigging points, thus saving time and money.