ENVIRONMENTAL chiefs warned businesses "will be held to account" for pollution breaches in the wake of two successful prosecutions against firms behind two major sewage leaks.

Scottish Water has been fined £17,000 over an incident in 2014 which saw an estimated two million litres of untreated sewage released into the Red Burn in Cumbernauld, killing fish and causing contamination that stretched more than one and a half miles (2.5km) downstream.

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In a separate case, farm partnership McCreery and Sons was fined £1,200 for repeatedly discharging slurry and silage into the Gifford Water in East Lothian.

Terry A’Hearn, chief executive of the Scottish Environment Protection Agency (Sepa), said: “Both these incidents caused damage to those water bodies, both these incidents caused fish mortalities, and both these incidents should not have happened. So we’re disappointed that they took place but we’re pleased that both organisations have been held to account.

“This is at the core of our One Planet Prosperity regulatory strategy. Businesses and organisations that do the right thing for the environment will be supported by SEPA, they’ll be helped to keep doing the right thing and do even better. Those that get it wrong will be held to account in this way.”

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Sepa said the prosecutions, which have both come to court during the past month, highlight the importance of managing farm effluents and maintaining critical water treatment infrastructure.

In the Scottish Water case, investigators discovered that macerators, which are required to reduce solids to small pieces, had become blocked and material backed up during a period when the Dunnswood Sewage Treatment Works was unmanned. Sewage was then discharged via an emergency overflow outflow pipe into the Red Burn.

It is a condition of the site's licence that such as event should have triggered telemetry warning signals to be sent to Scottish Water’s control room, raising the alarm. However this did not happen and, as a result, the operator did not immediately send staff to rectify the issue. The leak continued for 17 hours.

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Scottish Water was fined over the incident following at hearing at Airdrie Sheriff Court on February 7.

Callum Waddell, SEPA’s reporting officer, said: "This unauthorised discharge, along with the low flow in the watercourse due to a recent dry spell of weather, resulted in a number of fish being killed.

“SEPA is very clear that compliance with regulations designed to protect the environment is not optional. If telemetry systems had been working properly then Scottish Water would have received the alarm and sent an operative to the site to rectify matters.”

David McCreery and Sons, which runs Yester Mains Farm, also plead guilty at Edinburgh Sheriff Court on January 18 to repeatedly discharging slurry and silage to unnamed tributaries of the Gifford Water in 2014, causing pollution to the receiving waters and harm to fish and invertebrate populations.

SEPA investigators discovered various problems including overfilled silage bays, cracks in the rear wall of the silo, and an overflowing slurry pond.

Pamela Mackay, SEPA’s reporting officer, said: “The silage pollution could have been avoided if the correct storage practices had been followed and the silo had been maintained."