Barhale completes phosphorus removal upgrade in West Yorkshire

Wastewater plants across the UK are tightening nutrient discharge limits to protect receiving rivers and meet environmental permits. In this context, an £18 million treatment upgrade introducing new settlement, dosing and certified monitoring systems has been commissioned at Dewsbury Wastewater Treatment Works by BarhaleEnpure JV.

Meeting river quality limits through process redesign
The Dewsbury WwTW serves a population equivalent of about 200,000 people and discharges into the River Calder. The completed scheme achieved a 90% reduction in phosphorus concentration in final effluent, exceeding Water Industry National Environment Programme (WINEP) targets for England.

Phosphorus originates largely from domestic detergents and personal care products, with additional inputs from runoff and soil erosion. Elevated concentrations promote eutrophication, increasing algae growth and reducing dissolved oxygen in rivers, making removal a priority in regulated wastewater treatment infrastructure.

Fewer tanks, larger volume
Fourteen existing primary settlement tanks were replaced by three larger units and two primary sludge pumping stations. Before construction, a local beck was diverted to accommodate the footprint.

The new circular tanks measure 45 meters in diameter and 8.5 meters deep at the desludge cone. Concrete wall sections were precast off-site and assembled on location, reducing on-site construction duration and enabling installation while the plant remained operational.

The facility continued full treatment operations throughout the project, maintaining compliance during construction — a typical constraint in live wastewater treatment upgrades.



Dewsbury Wastewater Treatment Works (WwTW) - new settlement tanks.

Chemical dosing and certified monitoring
A new chemical dosing plant supports phosphorus removal through precipitation processes commonly based on iron or aluminium salts. Monitoring capability was upgraded using a UMON4 device certified under MCERTS standards.

The monitoring system verifies that the plant is treating the permitted flow of 2,350 L/s to full treatment even during storm overflow operation. This supports regulatory compliance documentation within a digital supply chain of environmental reporting, where continuous measurement data forms part of permit validation.

Operational resilience and environmental integration
Process improvements were introduced alongside construction, and a 2.5-hectare biodiversity and rewilding area was created around the site.

The project progressed from early contractor involvement into design-and-construct execution in the third quarter of 2023. Yorkshire Water plans further nutrient-reduction programmes, with more than £350 million allocated to phosphorus reduction across 85 wastewater treatment sites between 2020 and 2025.

The Dewsbury upgrade demonstrates how hydraulic capacity changes, precipitation dosing and certified monitoring can be combined to meet tighter nutrient discharge limits while maintaining continuous treatment operation.

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