The contractor is progressing design development, surveys, ground investigations, enabling works and site preparation at Blackburn Wastewater Treatment Works ahead of a decision on the main construction phase.

The scheme is being developed through United Utilities’ Enterprise delivery model, which brings together the water company’s operational, design and construction teams with specialist suppliers from an early stage.

Subject to planning and final approval, the project will see new thermal hydrolysis and advanced anaerobic digestion facilities built.

The upgraded plant would be capable of treating an average of around 45,000 tonnes of dry solids a year, with extra capacity to cope with seasonal demand and population growth.

United Utilities expects the new process to lift renewable biogas production by around 20% compared with the conventional anaerobic digestion system currently used at Blackburn.

The completed facility is projected to produce around 127,000 MWh of renewable biogas energy each year.

United Utilities already operates the technology at its Davyhulme wastewater treatment works in Manchester, where biogas is used to generate renewable electricity and biomethane.

Kier Infrastructure managing director for water Andy Lingham said: “Our £29m package is progressing the design and early works while United Utilities continues through the planning and approval process.”

The scope and timing of the main construction phase will be confirmed once planning permission and final project approval are secured.