Investigation underway after video appears to show untreated sewage being released into River Thames

An investigation is underway after a video was released, which appears to show untreated sewage being released into the River Thames in Oxfordshire.

The footage was filmed by the Windrush Against Sewage Pollution group. They say large particles of waste can be seen emerging from an outflow pipe at the Cassington treatment works near Witney.

Reading-based water company Thames Water said no sewage has been released there since March last year, but said an investigation has been launched.

Ash Smith, from Windrush Against Sewage Pollution said, "We reported this to the Environment Agency on 12 January, and we have been in touch with the water company.

"We have been to the works, and we still have concerns about what is coming out. This is ongoing and we will be showing the water industry some more. Hopefully they will come up with a better answer."

Ash Smith, Windrush Against Sewage Pollution

A Thames Water spokesperson said: “Cassington sewage treatment works has not discharged untreated sewage since March 2021.

"The treated effluent has been of a consistently high standard, and an assessment of the watercourse on January 17 found the river area was in good health with very low ammonia levels and high dissolved oxygen.

"We invited WASP to look around the site on Wednesday and discuss what they have seen in the river. They saw the good quality of the final effluent that is released from the sewage works, so any problem seems to be occurring in the long pipe that takes the treated effluent to the river.

"We are determined to understand what is coming out of the final effluent pipe and we have taken further samples as part of our examination. These samples are currently being tested and we are waiting for their results.

“We regard all discharges of untreated sewage as unacceptable and will work with the government, Ofwat and the Environment Agency to accelerate work to stop them being necessary and are determined to be transparent. Our aim will always be to try and do the right thing for our rivers and for the communities who love and value them. We have a long way to go – and we certainly can’t do it on our own – but the ambition is clear.” 

Thames Water say their solids effluent output from the STW is well below what their EA permit allows Credit: Thames Water

According to the water firm, their solids effluent output from the STW is well below what their Environment Agency permit allows.

They also add that Cassington web cameras on its storm tanks shows that they have not discharged since March 2021.