“Polyethylene is an excellent material for drinking water distribution mains.” These are the words by Mike Shepherd, Senior Consultant – Networks – for Thames Water Utilities Ltd. He was involved in the major project of renewing London’s Victorian Water Mains in which plastic pipeline systems play a key role.
Thames Water Utilities provides water and wastewater services 24 hours a day, 7 days a week to more than 13 million customers in London and across the Thames Valley. Drinking water is supplied via a network of over 32,000km of water mains. However, in metropolitan London, over half of these pipes are more than 100 years old.
Due to corrosion, ground movements in the aggressive London clay and the additional loadings arising from the increased volume of traffic, some of these older pipes are reaching the end of their service lives. In 2003, Thames Water therefore started a major project to renew these pipes. The company uses plastic pipeline systems for water distribution mains in sizes up to and including 315 mm.
“We are renewing these water mains so that there are fewer bursts and leaks and so we can continue to provide high levels of service to our customers in the future,” says Mike Shepherd from Thames Water.
He emphasized the importance of using polyethylene pipeline systems in the project. Firstly, they do not corrode and are very flexible. Secondly, the welded jointing system means no leakage, and thirdly, they allow the use of trenchless installation techniques. This last benefit is extremely important especially in a congested metropolis such as London.
Trenchless techniques reduce the amounts of excavation required and hence the amount of soil to be removed and imported backfill to be obtained. Furthermore, they generally mean quicker installation and hence less disruption for traffic and the public in general. These are significant environmental benefits which are important to Thames Water and its customers.
The Victorian Water Mains renewal project will replace over 1,300 km of mains by 2010.