Pioneering pigs

A pioneering experiment using ice could prove to be the way forward for removing iron from water mains.

Wessex Water said that a trial by Bristol University researchers along a small stretch of main was so successful that it may have been just the 'tip of the iceberg' for things to come.

Traditionally, polyurethane foam swabs known as solid plugs or pigs were propelled through the main with water, scouring the pipe clean as they went. However, early indications show that 'ice pigs', new products that underwent testing in the Wessex Water region, have eliminated several problems caused by the conventional process.

Ice pigging involves cleaning by injecting ice slush into a rising main before forcing it through the pipe with water. The trial, which took place over a 1.6km stretch of a 150mm-diameter potable raw main in West Lavington, Wiltshire, produced results deemed ideal for pipe cleaning.

Although solid plugs have been used successfully for a number of years to clear and clean pipes in various industries using common methods such as foam swabbing and air scouring, the process has several drawbacks apparent when used in complex pipes.