Scottish Water was fined £7,500 at Dornoch Sheriff Court on Monday for allowing untreated sewage to discharge to a Brora burn for a week, resulting in a number of fish deaths.

The company pled guilty to failing to comply with a condition in their water use licence in allowing the continued discharge of untreated sewage effluent into the Clyne Burn, causing the death of fish and producing a significant amount of fungus. The pollution incident was investigated by the Scottish Environment Protection Agency (SEPA) and a report submitted to the Procurator Fiscal.

SEPA officers were alerted to the presence of dead fish in the Clyne Burn by a member of the public on 1 September 2010. On investigating they found 55 dead trout at the mouth of the burn and sewage fungus over a 1.4 kilometre stretch, starting at Scottish Water's Victoria Road pumping station in Brora. 

Problem caused by pumping station failure

Investigations revealed that there had been a problem at the pumping station when an airlock prevented waste, including sewage and distillery effluent, being pumped on. This caused the wet well, which is used as short term storage when there is a problem (such as pumps malfunctioning or an overload of water during a storm event) to fill up. As the airlock was not cleared, the level in the wet well continued to rise until it went past the spill level and began to discharge to the Clyne Burn. 

Andrew Steel, SEPA's investigating officer, said: 

"Telemetry data provided by Scottish Water showed that the wet-well level in the pumping station rose to the spill level on 25 August and continued to stay above that level until operators attended the site on a routine inspection visit on 1 September. This means that for around seven days all sewage from the sewerage network upstream of the pumping station was discharged to the Clyne burn.  Once the airlock was cleared the pumping station returned to full function." 

"This situation could have been prevented if Scottish Water staff had checked and interpreted telemetry trends, alerting them to the fact that the wet well levels continued to be at a high level while pumps were running, for far longer than would be expected following heavy rainfall."