United Utilities PLC has completed an Enforcement Undertaking following a pollution incident where spill of acidic ferric salt solution from Rivington Water Treatment Works caused a significant fish kill in the River Douglas at Horwich.

United Utilities offered the Enforcement Undertaking in response to the incident which was investigated by the Environment Agency in September 2016.

The Environment Agency accepted the offer which included a payment of £500,000 to the Douglas Catchment Partnership, led by the environmental charity Groundworks, for the building of fish passages or bypass streams, within the River Douglas catchment and further pro bono support to the project, which will directly benefit the local environment.

United Utilities have also spent £88,498 on actions to prevent a recurrence of the incident, which included improvements to the chemical delivery area, tank cleaning and maintenance and valve replacement. They also paid £13,521 in Environment Agency costs.

Enforcement Undertakings address both the cause and effect of the offending. Polluters can make an offer to the Environment Agency to pay for or carry out environmental improvements as an alternative to any other enforcement action and the Environment Agency decides whether this is acceptable. Enforcement Undertakings differ to cases which are dealt with in court, as they result in money being spent directly protecting, restoring and improving the environment.

Environment Agency officers investigating found the River Douglas, which flows out of Rivington Reservoir, to be very acidic (a very low pH) which had impacted the river, turned it an orange colour, and caused a significant number of brown trout to be killed. It was discovered that ferric solution had been by-passing a faulty valve in the water treatment works, which had discharged into a drain and entered the river.

The water company cooperated with the Environment Agency’s investigation, admitted the offence, implemented works to try to prevent the pollution continuing and carried out improvements to prevent a recurrence.

Jennifer Hall, Land and Water Team Leader at the Environment Agency, said:

“Environment Agency staff respond to pollution incidents 24/7 to contain pollution and protect water quality. We investigate pollution incidents to find the source, stop the problem and understand how best to reduce any impacts on local communities and the environment. We take tough action against any company or individual who causes significant pollution and damage to the environment.”

“Over the course of the past year the number of serious and significant pollution incidents reduced to their lowest levels since 2011 but there are still far too many serious pollution incidents which damage the local environment, threaten wildlife and, in the worst cases, put the public at risk.”