South West Water fined for sewage treatment offences in Dartmouth and Salcombe

South West Water has been ordered to pay £71,800 in fines and costs for failing to correct faults at sewage treatments works in two of Devon’s most popular coastal towns. The prosecution was brought by the Environment Agency.

Problems at the company’s sewage treatment works in Salcombe and Dartmouth culminated in the sites breaching their environmental permits. Both sites suffer from saline (sea) water infiltration, however the main issue was failure to manage and maintain processes and infrastructure at the two sites between 2015 and 2016.

Salcombe treatment works serves Salcombe and the nearby village of Malborough. Sewage pipes upstream of the works cross the estuary foreshore and are submerged at high tide. Some of these pipes have faults that allow saline water to enter the sewer network. The treatment process, that involves the use of bacteria to break down effluent, cannot treat excessively salty sewage.

Excessive salinity can damage or kill bacteria used to break down the effluent and prevents the biological treatment process from operating properly. It can prevent suspended solids from breaking down adequately and disrupt the final stage of ultraviolet disinfection before effluent is discharged into the Kingsbridge estuary.

In 2016 SWW received a report from consultants that said it could not treat the volume of sewage produced in Salcombe to the required standard during the summer months because of the town’s increased summer population.

Between September 2014 and August 2016, Salcombe sewage treatment works breached its permit by repeatedly exceeding the maximum number of non-compliant samples it was allowed.
South West Water is permitted to discharge sewage effluent tainted with saline in an emergency. This normally occurs when saline has be diverted away from the normal treatment process, but the holding tank is full.

In September 2015, the Environment Agency expressed concerns at the frequency of discharges from the saline balancing tank, which holds effluent mixed with saline until it is ready to enter the treatment process. Between 3 February 2015 and 2 May 2015 there had been 36 discharges – one of which lasted 53 hours.
                                                                                                               
The court heard there were similar seawater ingress and equipment failure problems at Dartmouth sewage treatment works. In January 2015, a valve that keeps seawater out of the sewer was identified as in need of replacement, but wasn’t finally replaced until October 2015. The eight-month delay would have resulted in a worsening saline ingress problem.

“The Environment Agency uses the environmental permitting regime to protect and enhance the environment for current and future generations. South West Water’s repeated failure to comply with the conditions of its permit at Salcombe and Dartmouth meant that effluent which had not been fully treated was being released into the water environment. We are working closely with the water company to improve permit compliance and reduce waste water pollution,” said Helen Todd for the Environment Agency.

Appearing before Exeter Crown Court, South West Water was fined a total of £50,000 and ordered to pay £21,800 costs after pleading guilty at an earlier hearing to two offences under the Environmental Permitting Regulations 2010.