Thames Water fined £380k for polluting stream

The Environment Agency said it brought the case against Thames Water after pollution from its site at Princes Risborough sewage treatment works entered Horsenden Stream.

The stream is part of the River Thame catchment area in the Chilterns, and named an Area of Outstanding Natural Beauty.

A biological survey of the stream noted that the impact of the sewage was chronic and was likely to have been prevalent for some time

Holly Linham, EA environment officer

Thames Water pleaded guilty at Wycombe Magistrates Court on August 5 last year and was committed to Aylesbury Crown Court for sentence.

On Monday this week the company was fined £380,000 and also ordered to pay costs of £23,093.

The Environment Agency blamed ongoing management failures at the sewage treatment works which caused the company to breach the site permit on a number of occasions between February and July 2013.

There were also additional technical problems, it said. Inlet screens, designed to prevent debris from entering the works and causing blockages, were not working, and the storm tank pump was broken.

It said the site’s storm weir had also been set too low which meant that discharges were happening when the effluent should have been passing through the works for treatment.

Conditions observed by Environment Agency officers during visits were not isolated incidents, it claimed.

“Our officers attended the site where they walked the Horsenden Stream and saw thick layers of sewage fungus carpeting the river bed and plants,” said Holly Linham, environment officer at the Environment Agency.

“A biological survey of the stream noted that the impact of the sewage was chronic and was likely to have been prevalent for some time.”

Thames Water has since changed the management structure at the site and raised the storm weir, said the Environment Agency, helping to improve conditions at the stream.