MOLSON Coors Brewery (UK) Limited has been fined £100,000 and ordered to pay costs of £31,586.49 for polluting the River Wey.

Basingstoke magistrates heard that the river was polluted between June 24 and September 4, 2013.

In a case brought by the Environment Agency, Molson Coors Brewery Ltd was in court last Thursday for polluting the River Wey and the Lasham Drain, a tributary of the Wey which carries surface water run-off from the brewery site.

The brewing company pleaded guilty to two offences – causing water discharge and breaching the condition of its environmental permit with respect to monitoring the Lasham Drain for fungus. The offences resulted in the discharge of process trade effluent from the installation activities at the brewing giant’s site on Turk Street, Alton, into the Lasham Drain and causing pollution which went undetected.

The court heard there had been gutters on the building known as the “boiler room” located next to a trade effluent chamber that ran directly to the Lasham Drain. The gutters had been removed when the building was extended and the chamber was converted from a storm water drain to a trade waste effluent drain from this section of the building.

When the alterations were made the contractors had used a liner which did not seal the chamber to divert the trade effluent, which resulted in not completely blocking the existing pipe and pathway to the Lasham Drain.

The Environment Agency first received reports of the presence of fungus in the stream as it ran alongside Waterside Court in Alton before flowing along the River Wey, through the Mill Lane trading estate toward Holybourne. An Environment Agency officer checked the watercourse and confirmed that a lot of fungus was present at Waterside Court.

Environmental officers traced the pollution to Molson Coors’ premises where a discharge of trade effluent was seen to be entering the Lasham Drain culvert within the brewery. The effluent was discovered to be flowing into the Lasham Drain culvert through cracks and defects in the chamber.

The company had also failed to respond to the regular monitoring and visual inspections that it was obliged to carry out as a requirement of the permit issued by the Environment Agency. This monitoring clearly indicated a serious problem in the Lasham Drain but Molson Coors Brewery Ltd failed to act upon this information.

The drainage problems at Molson Coors which caused the pollution led to a significant reduction in the water’s biological quality at Lasham Drain and downstream in the Northern Wey, compared with that of the upstream control site. The presence of large quantities of sewage fungus indicated that very high nutrient organic matter was entering the Lasham Drain.

Paul Greaves, a senior Environment Agency officer, said: “We take these types of incidents very seriously and will do everything within our powers to safeguard the environment and people affected, and that includes bringing those who harm the environment to account for their actions.

“It is important that the courts send out a clear message to all companies operating in this sector. Regulations are there to protect the environment and that the courts will act firmly where regulations are breached and where the environment is either damaged or put at risk of damage.”

A Molson Coors spokesman said: “We are serious about our commitment to environmental compliance and we have a long and respectful history of maintaining the water course around the Alton brewery site. We regret this isolated incident. We wholly respect the magistrates’ decision and recognise this matter is now closed.”

The Alton brewery, which was still in operation at the time, was closed last May, ending 52 years of brewing on the Manor Park site. It is currently being decommissioned ahead of redevelopment.