United Utilities has been fined £400k for what was described as a ‘ catastrophic failure’ in an incident at the firm’s Stockport Waste Treatment Works.
In a prosecution brought by the Environment Agency, United Utilities admitted two breaches of environmental permit conditions and was fined £200,000 for each offence at Manchester Crown Court last Wednesday.
A gas holder which was part of the sludge treatment system suffered a ‘catastrophic failure’ and tilted sideways, leading to 50,000 cubic metres of biogas to escape for three weeks . The potential contribution to the greenhouse effect in the atmosphere from the biogas – which contained methane and hydrogen sulphide -was equivalent to 456 tonnes of carbon dioxide.
Commenting on the case, an Environment Agency spokesman said:
“ The gas holder was ageing and nearing the end of its useful life and there had been problems with it prior to the incident. The company had failed to adequately maintain the gas holder and act upon recommendations in its own inspection reports and had not properly addressed the risks associated with this ageing asset.”
Representatives from United Utilities said maintenance was adequate at the site when interviewed under caution, and that the company had reacted quickly in response to the incident with enhanced procedures.
With the UK government demanding a 50% reduction in storm overflow spills by 2029, the era of reactive management is over. Speaking in the House of Commons on 21 July 2025, then environment secretary Steve Reed said, “This Government will cut water companies’ sewage pollution in half by the end of the decade.”
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