Sewer upgrade improves water quality in the River Calder and Pendle Water

A project to create a vast new underground stormwater storage tank is progressing well in Nelson.

When complete, the tank on Lindred Road in the Lomeshaye Industrial Estate will be 20 metres deep and 15 metres wide and hold almost 2,000 cubic metres of storm water.

It will give Pendle’s sewer system additional capacity during times of heavy rainfall, and help to further improve water quality in nearby Pendle Water by reducing storm water discharges.

Construction of the tank has reached the halfway point – the deepest point has been reached and work will now begin to cast the base before installing pumps and pipework, installing the roof slab and connecting it into the existing sewer network. Work is expected to be completed by early 2024.  

The wastewater upgrade in Nelson is part of a wider £75m investment programme to deliver improvements to Pendle Water and the River Calder. The four-part programme also involves a major upgrade to Burnley’s Wastewater Treatment Works, improvements at Hyndburn Wastewater Treatment Works and the introduction of control flow improvements on the sewer network in Altham.

Senior Project Manager Tony Elliott explained: “The combination of population growth and climate change puts extra pressure on sewer systems. More people and a warmer, wetter climate means there is more rainfall entering the system.

“By increasing sewer capacity across the local area network, upgrading Burnley Wastewater Treatment Works, and carrying out improvements at Hyndburn Wastewater Treatment Works this investment will improve water quality in Pendle Water and the River Calder.”

As well as the new storm tank in Pendle, work is also well underway to upgrade Burnley Wastewater Treatment Works. This includes a new plant where air is injected into raw sewage to encourage bacteria to literally ‘feed’ on it. Additionally, an innovative technology called Biomag where iron oxide particles are added to reduce phosphorous levels is also being introduced.

Tony added: “We are acutely aware that these large projects can bring inconvenience and we are very grateful to the ongoing patience of site neighbours. For the Lindred Road tank we were able to make some modifications to the design so we could minimise the work needed in the road itself.

Between 2020 and 2025, United Utilities is investing £230m in schemes to capture and treat more storm water, improving 184km of waterways.