United Utilities give tour of Windermere Wastewater Works

The water company has faced criticism from politicians, community groups and activists over the extent of the storm sewage discharges into bodies of water such as Windermere. Legally, water companies are only allowed to discharge in periods of exceptional rainfall. 

Once the water reaches a certain level in this tank the sewage will be discharged as storm overflow (Image: Newsquest, Daniel Pye)

The regulator the Environment Agency (EA) served an enforcement notice to reduce sewage spills at the Cark in Cartmel pumping station after local residents found out that there had been hundreds of discharges between 2018-21 through a freedom of information request in August 2022.

UU said it had scheduled improvement works for the pumping station and that it took its 'environmental responsibilities very seriously.' 

In response UU has taken tours around its large water treatment sites at Windermere and Ambleside. 

Alan Luty holding a bottle of untreated sewage, which was quite diluted due to the plant still processing a high volume of rainwater (Image: Newsquest, Daniel Pye)

The site takes in not only sewage but rainfall and standing groundwater that has not been removed through culverts.

Kevin Sayers, the area stakeholder manager for UU, argued that this extra water is what causes the overflows and that this will have to be resolved in the next decade, especially if there is more rain as a result of climate change. 

The water arrives at a tank, which the site engineers called 'our Olympic-sized swimming pool.' 

READ MORE: Action taken by Environment Agency over Cark Pumping Station

Once the water gets to a certain level within the tank UU said that this is considered an overspill and it is legally allowed to discharge in accordance with the regulator. The tank was installed recently and UU argues that it has since reduced sewage discharges from the site.

The treatment works with Windermere in the background (Image: Newsquest, Daniel Pye)

The sewage water is then carried to a set of filters, which removes foreign 'media' from the effluent. The objects are carried up by an escalator that looks like a large cheese grater, with holes allowing the water through. 

Nappies, sanitary towels, and other objects flushed down toilets end up in a skip as a large 'fatberg' which is then sent to a landfill. The site engineers said that they are occasionally asked to find wedding rings. UU has put launched a campaign to stop the public from flushing down anything that is not 'pee, poo and paper.' 

Area business manager Simon Holding with a treated bottle of water (Image: Newsquest, Daniel Pye)

Ammonia, phosphorus and other toxic chemicals found in sewage are filtered through bacteria which changes these pollutants into nitrogen. Finally, it goes through UV treatment to further disinfect the water.