Construction work will start in spring 2010 to significantly reduce the amount of storm sewage that overflows into the River Thames during heavy rainfall when Mogden Sewage Treatment Works in west London becomes overloaded.
The £150M project, due to be completed in 2013, will enable the site to treat more than 50% more sewage than at present, so it can cope with heavy rainfall.
“As well as significantly reducing sewage discharges, these improvements will help reduce odour at the site.”
Steve Shine, Thames Water
Before construction work gets under way in Spring 2010, parts of Mogden’s western embankment will be cleared, including the removal of trees and shrubs ahead of bird-nesting season. When the project is completed, the embankment will be reshaped and the landscape enhanced for local wildlife. All this work will take place within the existing site boundary.
Planning permission for the project was granted on the condition that the Mogden works would comply with strict conditions aimed at reducing the smells and keeping local residents informed.
This was after residents’ complaints led the London Borough of Hounslow to serve an odour abatement notice on Thames Water in 2001.
Thames Water chief operating officer Steve Shine said the work is “fundamental” to improving the quality of the Thames. “We inherited a Victorian sewerage system, which is struggling to cope with the demands of 21st century London,” he said.
“Although our sewage works operate well under stable, dry weather conditions, in heavy rainfall excess flows pass through storm tanks, which provide a lower standard of treatment, and overflow into the tidal stretches of the River Thames − rather than having sewage back up on to the streets or even into people’s homes.
“The improvements at Mogden Sewage Works, which currently serves 1.9M Londoners, will enable the site to treat 50% more sewage and allow for a 6% population increase until 2021.
“As well as significantly reducing sewage discharges, these improvements will help reduce odour at the site, as the use of storm tanks during heavy rainfall will be reduced, and new and existing equipment will be covered over.”
The work at Mogden forms part of Thames Water’s wider London Tideway Improvements programme. This is made up of three major schemes: the Lee Tunnel, Thames Tunnel and Sewage Works Upgrades.