Wedoany.com Report on Feb 24th, Thames Water has invested £20 million to upgrade the Chesham Wastewater Treatment Works, significantly improving water quality in the River Chess. Through a new phosphorus reduction scheme, the plant will lower phosphorus levels from 2 milligrams per litre to 0.25 milligrams per litre, supporting a healthier and more balanced river ecosystem.
The treatment capacity at Chesham Wastewater Treatment Works has increased from 241 litres per second to 353 litres per second, enhancing wastewater processing capabilities and reducing the risk of overflows during heavy rainfall or groundwater infiltration. This upgrade is a key initiative by Thames Water to improve water quality in the River Chess, complementing river restoration projects along its course to increase vegetation, improve habitats, and boost biodiversity.
Stephen Horn, Coordinator of the Chess Smarter Catchment Project in the Chilterns National Landscape, stated: "The upgrade at Chesham Wastewater Treatment Works represents the most significant step taken so far to improve water quality in the River Chess." Professor Mike Bowes, a nutrient water chemist at the UK Centre for Ecology & Hydrology, added: "The phosphorus reduction scheme has already had a measurable impact on water quality, significantly reducing phosphorus concentrations in the River Chess since its implementation in late 2024."
The Chess Smarter Catchment Project has received £3 million in investment from Thames Water over the past five years, with a further commitment of £2 million to support partners and communities in implementing chalk stream restoration plans. Chris McKenna, Thames Water's Operations Manager for Colne and Maidenhead, emphasised: "We are committed to protecting river health, but it requires everyone's collective effort to help our waterways thrive."
Paul Jennings, Chairman of the River Chess Association, noted that since 2019, Thames Water's investment has led to improvements in wildlife populations, but challenges such as groundwater infiltration still need to be addressed. A recent report from the Zoological Society of London indicates a continued decline in dissolved phosphorus concentrations in the River Thames, which may be linked to improvements at wastewater treatment plants.
