Northumbrian Water has started work on a £4.2 million upgrade of Stressholme Sewage Treatment Works (STW) near Darlington – the upgrade is the first AMP8 Integrated Delivery Services (IDS) project, marking a major milestone in the company’s £3.6 billion five-year investment plan.

Northumbrian Water has started work on a £4.2 million upgrade of Stressholme Sewage Treatment Works (STW) near Darlington – the upgrade is the first AMP8 Integrated Delivery Services (IDS) project, marking a major milestone in the company’s £3.6 billion five-year investment plan.

Stressholme STW is the site of a multi million pound dewatering project which began in April 2025 and is on track to be delivered on time and within budget by Autumn 2025.

This project is the first to be delivered through Northumbrian Water’s newly established short-cycle ecosystem, which sits alongside the Living Water Enterprise the option for long-cycle investment. Together, these two models offer Northumbrian Water a flexible and effective framework to deliver its ambitious investment programme throughout the 2025–2030 asset management period (AMP).

The IDS team operates an integrated delivery model with ecosystem partners, combining in-house and partner expertise to deliver the best outcomes on shorter cycle, lower complexity work. The local organisations that form the ecosystem will play a vital role in helping Northumbrian Water to deliver its AMP8 programme and beyond, driving innovation and supporting regional growth.

Together with its partner, AE Yates, Northumbrian Water is installing a new centrifuge that will enhance the site’s ability to separate solids from liquids in wastewater. This upgrade will reduce waste volume and produce an even cleaner treated water for return to the environment.

The remaining sludge will be sent to Bran Sands STW, where it will be used to create green energy. Northumbrian Water has invested in the process at Bran Sands, Teesside and Howdon, Tyneside and says it is the only water company to use 100% of its sewage sludge to create green energy.

The project is also delivering embodied carbon savings of over 91 tonnes - the team are making the savings through sustainable construction methods including:

• Reusing steel piles from the oil and gas industry.
• Recycling aggregates for on-site use.
• Using recycled polypropylene components instead of cement and steel.
• Retaining materials on-site to reduce transport emissions.

Alastair Tawn, Northumbrian Water’s Head of Integrated Delivery Services – the team leading on the investment, said:

"Beginning work at Stressholme Sewage Treatment Works marks a significant milestone, this is the first of many projects to be delivered through our new ecosystem of local partners, created to help us deliver on our major investment programme, and it sets the tone for what’s to come. By working collaboratively with organisations like AE Yates, we’re not only delivering specialist capabilities and driving best value, but we’re also creating jobs and supporting regional growth…...

"The embodied carbon savings achieved at Stressholme demonstrate the power of partnership in delivering innovative, environmentally responsible infrastructure. This is just the beginning of a transformative journey for Northumbrian Water, the communities we work in and our customers.”

Gary Reeves, Contract Manager at AE Yates, added:

“It’s a privilege to be part of Northumbrian Water’s new ecosystem. The support from the team has made our onboarding seamless, and we’re proud to contribute to a project that’s driving innovation and delivering real value.”