Dairy Crest, now known as Saputo Dairy UK, has been fined over £1.5 million after pleading guilty to numerous pollution charges brought by the Environment Agency.
The cheesemaker, which produces brands such as Cathedral City at its Davidstow plant in Cornwall, had pleaded guilty to 21 of 27 charges.
The Environment Agency said the environmental performance of Dairy Crest had been "unacceptable for too long".
Dairy Crest, owned by Saputo Dairy UK, and its management of the Davidstow Creamery near Camelford, had been "falling way short of the standards expected".
Davidstow Creamery is the UK’s largest dairy processing facility and one of the largest manufacturing sites in Europe.
Each year it produces 57,000 tons of dairy products, and about 1.3 million litres of milk is brought to site daily from around 370 local dairy farms.
But Truro Crown Court heard that ever since the site changed production to focus on whey processing, particularly to produce powder used in baby milk, the effluent being discharged into the River Inny had been "more challenging to treat".
This had resulted in "unacceptable" pollution of the local river, which is a tributary of the River Tamar, causing "significant harm" to fish and other aquatic wildlife.
The court heard that another issue had been "foul odours which have often affected the lives of local residents".
For committing the offences, the firm was fined £1.52m at the crown court on 23 June 2022. It had already agreed to pay costs of nearly £273,000.
Delivering the sentence, Judge Simon Carr expressed the view that he had not seen consistent performance evidenced by the company over a five-year period.
The judge identified a poor, middle management culture as a contributing factor to the environmental harm caused that should have been dealt with by senior management much sooner.
He said it felt like there was never a time without a problem and some of those responsible for the wastewater treatment plant felt bullied and unable to come forward.
Judge Carr added he had been ‘moved’ when reading testimony from residents whose lives had been ‘blighted’ by odours.
Helen Dobby, area director of the Environment Agency, said: “As a large and well-established operator, Dairy Crest Limited should be up to the job of maintaining the required environmental standards.
"Instead, it has over a period of many years failed to comply with its environmental permit and not been able to protect local people and the environment.
“We acknowledge that Dairy Crest Limited has been taking steps to remedy the various problems, but unfortunately, these actions were not swift enough on many occasions and proved to be ineffective in stopping pollution.”
What are the offences?
The offences included:
• Releasing a harmful biocide, used to clean the wastewater tanks and pipework, into the river and killing thousands of fish over a 2km stretch on 16 August 2016.
• Coating the River Inny with a noxious, black sludge for 5km in 2018, through a release of a mass of suspended solids in July and August 2018.
• Consistently exceeding limits on substances like phosphorous and suspended solids entering the River Inny, from 2016 up to 2021.
• Numerous leaks of part-treated effluent into nearby watercourses and onto the land.
• Foul odours repeatedly affecting residents over many years.
• Failing to tell the Environment Agency within 24 hours of when things had gone significantly wrong on site, on 7 separate occasions.
