IN a bid to reduce the amount of sewage overflowing into the River Thames during heavy rain, Thames Water is about to start an upgrade of the Crossness sewage treatment works in Belvedere.

The £200m scheme will provide improvements to increase the amount of sewage treated at Crossness by 44 per cent.

This will prevent the sewage works becoming overloaded during downpours, resulting in the raw storm sewage which cannot be treated, overflowing into the river.

The upgrade at the plant in Belvedere Road which serves two million Londoners, will also allow for a six per cent increase in population to 2021.

In a first for a British sewage works, the project will include the installation of a wind turbine on the site which, combined with the energy generated from incinerating the sewage sludge, will generate up to half the power needed to run the treatment plant.

The project is part of a £650m upgrade to improve standards and capacity at London’s five main sewage treatment works.

Thames Water’s chief operating officer, Steve Shine, said the Victorian sewerage system was now struggling to cope with the demands of the 21st century.

He explained: “Although our sewage works operate well under stable, dry weather conditions, in heavy rainfall excess flows pass through the storm tanks, which provide a lower standard of treatment and overflow into the tidal stretches of the River Thames to avoid sewage backing up onto the streets or even into people’s homes.”

But before the main construction begins in the spring, more work is to be done to enhance the two Thames Water nature reserves - Crossness and the Southern Marshes - which border the Crossness plant.

Improvements will include creating suitable habitats for water voles and birds, clearing vegetation ahead of the bird nesting season, building a new temporary access road and installing a temporary 70m high anemometer.

This will provide information about wind speeds at the site, ahead of detailed design work on a new wind turbine, planned for 2013.