United Utilities has begun the biggest cleaning job ever performed by a UK water firm using pigs, in Lancashire.
The regions water firm is cleaning huge underground water mains as part of a £3.6bn investment to improve tap water quality.
The pigs − soft bullet shaped polyurethane foam plugs that are forced through pipelines to clean them − are named Big Mumma, Daisy Mae, Penelope and Jimmy Dean.
Each pig is 1.2m in diameter and can travel up to 22km once inside the water main. The pigs are based at United Utilities’ water treatment works in Franklaw, north of Preston.
Each pig has a different surface coating and hardness to ensure that naturally built-up deposits on the inside of the water pipe are carefully removed.
United Utilities water supplies and aqueducts manager John Butcher said: “Big Mumma can be a nightmare; at one point we thought we’d lost her in the pipe, she just won’t come out.
“We are using technology from the north sea oil and gas pipelines to keep a track on the herd, as they can go a bit wild.”
United is spending millions of pounds on the scheme of works, part of its £3.6bn pound investment programme across the region to improve the security and supply of drinking water.