South West Water was ordered to pay £7,500 in fines and costs after sewage escaped from an Exeter sewage treatment works into the River Exe. The case was brought by the Environment Agency.

Countess Wear is one of the largest sewage treatment works in Devon. It treats sewage from Exeter and surrounding villages.

On October 21, 2005 an Agency officer visited the works on a routine inspection and noticed the site’s storm tanks were overflowing.

The tanks are normally only used at times of heavy rainfall when the flows arriving at the works exceed the amount of sewage that can be treated.

The Agency officer checked the flow meter and saw that it was well below the threshold at which sewage should have been sent to the storm tanks. But instead, sewage was mistakenly diverted to the tanks resulting in illegal discharges to the estuary after the tanks filled up prematurely.

The water company is permitted, under the terms of its consent, to discharge sewage into the River Exe when the storm tanks are full. However, checks by the Environment Agency using data provided by South West Water, showed that the discharges were occurring more often than they should have been.

The Agency estimated that at times sewage was being discharged into the River Exe at a rate of up to 300 – 400 litres per second as a result of South West Water’s failure to ensure the required treatment flows. It was calculated that the total overflows would have been reduced by 84,107 cubic metres had the treatment works been operating correctly.

In July 2005 South West Water installed a new flow meter to accurately measure the flows arriving for treatment. However, magistrates heard the Environment Agency had ongoing concerns about the operation of the pumping station at the site.

‘This incident was avoidable. All South West Water had to do was operate the pumping system in a way that ensured it complied with its discharge consent. Its failure resulted in the discharge of considerable volumes of storm sewage into the environment. This posed a potential risk to shellfish beds downstream of the treatment works as well as the environment as a whole,’ said Dave Brogden for the Environment Agency.

Appearing before Cullompton magistrates today, South West Water, of Peninsula House, Rydon Lane, Exeter was fined £6,000 and ordered to pay £1,500 costs after pleading guilty to two offences under Water Resources Act 1991.