The incident occurred in July 2021 after a fat blockage in the waste drainage system of Moodiesburn-based Devro Scotland Ltd caused the contents of the effluent pipe to back up.
On reaching a dual manhole, the contents of the waste pipe then spilled over into the surface water pipe.
The surface water pipe, used for the drainage of surface and storm water, flows directly into the Bothlin Burn.
Evidence presented by procurators showed that approximately 1.8 million litres of a wastewater containing fat and chemicals flowed into the burn.
This included high levels of ammonia and elevated levels of Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD).
Samples taken by officers from the Scottish Environmental Protection Agency (SEPA) found those levels were sufficient to cause short-term gross pollution in the burn and were up to 350 times greater than the environmental quality standard for ammonia and up to 40 times greater than for BOD.
SEPA Ecology surveys concluded that the effects on aquatic life of the Bothlin Burn had been ‘devastating’, causing the deaths of fish and invertebrates.
The contamination provoked multiple calls to Scottish Water and SEPA from members of the public who reported the burn having a milky, opaque appearance and giving off a horrible smell.
The sentence was imposed at Airdrie Sheriff Court after the company pleaded guilty to a breach of water environment legislation. They were also ordered to pay a £3,600 victim surcharge.
Iain Batho, who leads on environmental matters for the Crown Office and Procurator Fiscal Service (COPFS), said:
"This incident was both foreseeable and preventable. Whilst Devro did take certain measures to prevent such an incident occurring, these measures were not sufficient.
“This is now the company’s second conviction involving them polluting the Bothlin Burn.
“This incident had a significant impact on the burn itself and the wildlife within it It also led to considerable public concern regarding water pollution.
“COPFS takes environmental crime seriously and will prosecute individuals and companies where there is sufficient evidence of a crime and where it is in the public interest to do so.”
The court heard that a regulated amount of wastewater normally flows from the plant to Dalmuir Waste Water Treatment Works for treatment before finally discharging to the River Clyde.
The cause of the discharge in this incident was a blockage - believed to be fat - in a foul sewer line within Devro.
Present within the plant was a ‘dual manhole’ drainage system where access can be obtained to both the ‘foul’ pipe and the ‘surface water’ pipe.
Both pipes run alongside each other and are ‘open’ at the top so that the flow within them can be viewed and inspected.
In this case, the blockage in the foul pipe caused the contents to back up and upon reaching the dual manhole the contents of that pipe spilled over into the surface water pipe and, consequently, the burn.
SEPA ecologists later indicated that aquatic life of the burn was adversely impacted by the discharge of BOD/COD and ammonia.
They reported a number of dead invertebrates and fish at several locations along the Bothlin Burn and the Luggie Water.