Chip maker McCain's 'sophisticated' facility to treat effluent going into sea off Scarborough

Campaigners have repeatedly raised concerns about its impact on water quality.

Swimmers are currently advised against bathing in South Bay – which is affected by a number of factors, including sewage entering the sea further north from Yorkshire Water's waste treatment plant.

A report in 2016 by the National Laboratory Service found evidence there were multiple factors at play, including pollution from humans and birds, but said data “gives strong evidence that the bacterial community from the industrial effluent has an influence in South Bay occasionally.”

McCain said it had announced a multi-year project to upgrade the site in 2017, including secondary treatment for the effluent.

This is defined as a biological treatment process “designed to reduce the amount of organic materials in the wastewater before it is discharged”. A statement said: “In close collaboration with the EA, in 2020 we enhanced our plans to further improve the water purification processes adding secondary treatment, one of the most sophisticated water treatment plants of its type in the UK.”

McCain says it has always been fully compliant with EA regulations. The new system will involve daily monitoring and testing.

Crab boat owner Bob Roberts has long been trying for answers from McCain, the EA and YW, which owns the outfall, over the waste water, which flows into the sea at a maximum rate of 5,446 cubic metres a day (2022 figures). He said: "Here we are in 2023 and the plant still isn't operational. It has taken far too long and we still don't know what's going into the bay. What will the discharge consist of in 2024? Will it be clean water or will it still be contaminated?

The town’s MP Sir Robert Goodwill said: “This idea that McCain is causing the beach to fail is rubbish. The reason it failed most recently is sewage.”

He said a huge storage tank built by YW on Marine Drive to take stormwater could not cope in a heavy downpour. Water firms were faced with a stark choice, “either discharge it to sea via their outfall – or turn it off and it would be backing up through manholes and running down the streets.”

McCain had spent £100m building a new factory on the site of the cold store and they could not do anything until the freed up land was available, he said, adding: “They can now invest in an anaerobic digestion plant for some of the starch and better treatment. They will still be discharging treated water.”

The EA said the McCain facility at Cayton is regulated through an environmental permit and the firm is “required to improve their effluent treatment by December 2023 in line with new Food and Drink Industry standards.”