Yorkshire Water completes £18m upgrade at Dewsbury Wastewater Treatment Works

Yorkshire Water has completed a major £18m upgrade to Dewsbury wastewater treatment works (WWTW) that will help improve water quality in the river Calder by removing Phosphorus from treated wastewater.

The scheme, delivered in partnership with BarhaleEnpureJV, saw 14 existing Primary Settlement Tanks (PST) replaced with three, new larger tanks and two new primary sludge pumping stations.  A new chemical dosing plant was added to help reduce Phosphorus levels in the final effluent to the environment following the treatment process. 

As well as the new chemical dosing system, process improvement and a 2.5-hectare biodiversity and rewilding area, the plant which serves a catchment of approximately 200,000 people, remained fully operational throughout the construction process.

Phosphorus is a normal part of domestic sewage, entering the sewer system via domestic showers and washing machines due to products such as shampoo and liquid detergent containing Phosphorus. It can also wash off from agricultural fields after the use of fertilisers and be dissolved from soil which can be difficult to control. 

While a small amount of Phosphorus is harmless and is an essential part of many ecosystems it can become damaging to aquatic life if levels are not controlled.  

These improvements exceed regulatory requirements, achieving around a 90% reduction in Phosphorus levels in the final effluent so that Dewsbury wastewater treatment works successfully meet water industry national environment programme (WINEP) targets for England.  

Philip Lister, environmental permit compliance lead, said: “Yorkshire Water is committed to looking at innovative ways to improve the operation of our sites to meet our Phosphorus removal targets.  This particular project adopted a number of measures designed to reduce the carbon impact and speed up the duration of the improvement works.

“We have committed over £350m to reduce the levels of Phosphorus going into watercourses at 85 of our wastewater treatment sites across the region in the next five years, continuing the work we began in 2020 - 2025.”

The project was delivered on schedule and under budget, using modern construction methods to reduce carbon, minimise disruption and maximise local benefits, including the use of local suppliers, apprenticeships and community engagement.

BarhaleEnpure JV contracts manager Brian Harrold said: “We have worked closely with Yorkshire Water to deliver this important phosphorous reduction project. It will significantly improve water quality in the River Calder, making it a healthier and more enjoyable environment for people and wildlife and increasing opportunities for recreation.”