Futureproofing Durham’s wastewater network and achieving WINEP drivers through strategic catchment planning and a smart transfer scheme

Durham Wastewater Transfer Scheme

To meet stringent phosphorus discharge limits by 2025, Northumbrian Water needed to transfer flows from the Plawsworth and Pity Me Sewage Treatment Works (STWs) to Brasside STW, which was set to undergo a future upgrade. They engaged us to provide civil engineering services as part of the team for this effort.

The project involved six kilometres (four miles) of new pipeline infrastructure, including around three kilometres (two miles) each of rising mains and gravity sewers. A standout feature of the scheme was a 120-metre (394-foot) pipe bridge. We designed the structure using motorway gantry principles, enabling gravity flow across challenging woodland terrain and avoiding the need for additional pumping, cutting both carbon and operational costs.

We also delivered a critical auger bore crossing under the East Coast Mainline, using real-time remote monitoring and close collaboration with Network Rail. The tunnelling was completed under live tracks with minimal ground movement and no remedial works required.

Designed for dual use, the infrastructure initially transfers final effluent and will later convey sewage, allowing the Plawsworth and Pity Me STWs to become redundant. The scheme’s phased approach supports future housing growth and aligns with Northumbrian Water’s Asset Management Plan (AMP) 8 strategy, offering a resilient, low-carbon solution that enhances value across regulatory cycles.

Delivered ahead of the Water Industry National Environment Programme (WINEP) regulatory deadline, the Durham transfers scheme not only met immediate environmental but also laid the groundwork for long-term catchment rationalisation.