United Utilities investing £6.1m to boost water quality in River Irwell

12 Jun 2023

A multi-million pound project to introduce new storm water storage tanks and updated wastewater treatment methods is nearing completion at Rossendale Wastewater Treatment Works.

The project is now in its final stages and is on track to be completed by late summer. Work to overhaul the facility has involved the introduction of two new above ground storm water tanks which will hold 6.5 million litres of water – more than two and half Olympic-sized swimming pools.

The tanks play an important role in helping United Utilities improve water quality as they will reduce the need for sewers to overflow in times of heavy rainfall.

New wastewater treatment methods have also been introduced which will reduce levels of phosphorous and ammonia in the final effluent released from the facility.

Programme Manager Paul Lowndes explained: “The combination of population growth and climate change puts extra pressure on sewer systems which have to cope with a mixture of rainfall and waste from homes and businesses. More people, more development and a warmer, wetter climate means there is more rainfall entering the system.

“The tanks act as ‘holding areas’ for the extra rainwater that enters the sewer network in times of heavy rainfall. Holding the extra water back means the treatment facility is less likely to become overwhelmed. When the storm passes, the excess water will be pumped back into the system for treatment.

Paul added: “We have also introduced new treatment methods which will improve the quality of the water that we release back into the River Irwell.”

During the last two years, United Utilities has reduced storm overflow operations by almost 40%, and is on track to improve almost 200km of rivers by 2025.

The company has also been granted approval to make an early start on £900m of investment which means that similar storm water storage projects across the region can get underway before 2025.