South West Water fined for sewage spill near shellfish beds

Boats moored on the river Fal, Cornwall.

South West Water has been ordered to pay £205,000 in fines and costs for discharging sewage into the Fal estuary in Cornwall. The case was brought by the Environment Agency.

On 26 August 2013 untreated sewage overflowed from the water company’s Newham sewage treatment works near Truro into the Fal, an internationally important shellfishery, Site of Special Scientific Interest (SSSI) and Special Area of Conservation (SAC).

The illegal spill occurred after a piece of redundant grating fell and partially blocked an inlet at the works, causing sewage to back up and overflow into the estuary via a storm storage outfall. The spill continued for about 9.5 hours, during which time enough sewage escaped to fill 4,563 bath tubs (730,000 litres).

The discharge occurred close to mussel and oyster beds at Malpas and Grimes Bar. These shellfisheries were temporarily closed by Cornwall Port Health Authority because of the possible risk of contamination by harmful viruses and bacteria such as Norovirus and e.coli.

The decision to close the shellfish beds was taken just before the start of the harvesting season (1 October). Sewage at the Newham treatment works normally undergoes a high level of treatment (tertiary) including ultra violet (UV) that kills bacteria and disinfects effluent.

An UV disinfection system is required at this site because of the Fal estuary’s designation as a shellfishery. The sewage discharged over a bank holiday on 26 August was settled and screened, but otherwise untreated and occurred outside of a storm event. This would have resulted in a significant increase in levels of bacteria in parts of the Fal estuary and meant the treatment works was in breach of its EA permit.