Thames Water’s Banbury sewage treatment works 'set to increase capacity by 84%'

TW is carrying out a £14.7 million upgrade at Banbury Sewage Treatment Works (STW).

It is part of a plan to upgrade 250 of its wastewater sites including Bloxham, Hanwell and Greatworth, to help manage demand caused by population growth and climate change, a spokesman said.

Sean Woodcock, MP for Banbury, recently visited the site alongside the Cropredy’s Women's Institute, to learn about the upgrades and the process of treating waste.

Concern has grown about water quality. A study of the 46 storm overflow locations in the Banbury area in 2023 showed raw sewage was discharged into the River Cherwell and River Ray on 1,969 occasions for over 24,000 hours.

The Banbury upgrade is expected to be completed by 2029 and will expand the site's flow capacity from 266 to 490 litres per second, an increase of 84%.

TW says this will greatly reduce the risk of storm overflows during spells of heavy rainfall and longer periods of groundwater retention, which can cause the sewer systems to be overwhelmed.

The site is also undergoing a phosphorus reduction scheme, which will improve the quality of effluent released into the river following treatment and is part of Thames Water’s upgrade plan.

Mark Ruinet, Senior Project Manager at Thames Water said: “As custodians of important infrastructure, we need to ensure our sites are resilient to the pressures of climate change and population growth so we can continue to provide reliable services to our customers.

"Our upgrades at Banbury sewage treatment works come as part of our commitment to help protect customers and the health of the rivers and waterways.

“We believe all discharges are unacceptable and we are committed to seeing healthy and thriving waterways. However we can’t do it alone. While we play an important role, we aren’t the sole custodians of river health. We need everyone working together to help our waterways thrive.”

TW invited the WI and MP to the site to showcase the improvements they are making and demonstrate the process of daily treatment of wastewater.