Northumbrian Water is investing £5.5 million in upgrading three of its sewage treatment works in County Durham.

The work at Windlestone Sewage Treatment Works (STW), Chilton Lane STW and Bishop Middleham STW will increase the capacity of the company’s network to reflect the growth of the local population.

It will also ensure that the area’s sewage continues to be treated to the highest possible standards to protect the environment.

The work, which is being carried out by Northumbrian Water’s trusted partner, Interserve, is due to start on all three sites on Monday, March 20. The upgrades are likely to be completed by early 2018.

At Windlestone STW, off the A689 south of Chilton, £5 million will be invested in the extension of the site to create an increase in capacity, alongside a general refurbishment of the existing facility. Bishop Middleham STW, off Foumarts Lane, and Chilton Lane STW, off Gipsy Lane, near Ferryhill Station, will receive general upgrades to ensure the continued high quality treatment of the area’s sewage.

Project Manager Charles Harman said: “As populations grow, so does the amount of sewage that requires treatment, so it is important that we continue to invest in our network to ensure we deliver the highest levels of service to our customers and that we have the capacity to continue doing this long into the future.

“Work will also involve taking measures to meet even tighter regulations on ammonia, improving the quality of local watercourses.

“All of the work on these projects will be contained on our sites, but we will be working to ensure local residents are aware of the nature of this investment and how it will support their community.”

Customers can keep in touch on 0345 7171100, or visit to request a call back from the project team.

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