Costain has transferred techniques proven in industrial cooling to a major wastewater scheme for United Utilities at Crewe Wastewater Treatment Works (WwTW) in Cheshire, helping deliver a phase of the programme ahead of schedule.

The project sits within United Utilities' Enterprise alliance, which brings together the utility, Costain and six other design and construction partners to deliver a £2.5bn package of major projects across AMP8. It underscores the wider opportunity for knowledge transfer and programme acceleration across the UK water sector as investment ramps up.

At Crewe WwTW, Costain is refurbishing two nitrifying trickling filter systems by installing new polypropylene pack media, manufactured and assembled in-house. The media supports the growth of nitrifying bacteria that remove ammonia from wastewater by converting it into nitrate, improving treatment performance.

The approach mirrors pack media use in cooling towers, where a large surface area enhances interaction between water and air to drive evaporative cooling. Drawing on more than two decades of industrial cooling experience in the energy sector, Costain has applied this process understanding to water treatment to optimise delivery and performance.

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Costain's application of these techniques, combined with a detailed understanding of site conditions, enabled the first phase of works to be brought forward by a year. Phased refurbishments will continue through 2026, with the team working with local supply chain partners to recycle the removed media and minimise environmental impact.

Mark Blackham, Head of Industrial Cooling at Costain, said: "This is the first time that we have applied our industrial cooling techniques to a water company, which has been made possible thanks to our decades-long experience and sophisticated process by which to assemble the pack media."

Mark Blackham continues: "The implementation is enabling us to deliver important upgrades to the wastewater infrastructure which will improve the quality of water in surrounding rivers and benefit local wildlife. We're looking forward to exploring subsequent opportunities to incorporate the techniques to projects in the water sector."

Richard Helme, Programme Director at Costain, said: "We have an excellent working relationship as a trusted partner to United Utilities. Part of that trust is built on our ability to apply innovative solutions to enable for the safe and efficient treatment of wastewater. By drawing on strong practices and capabilities from our colleagues in the energy sector, we've been able to deliver critical upgrades for United Utilities ahead of schedule."

Tony Slater, Enterprise Director at United Utilities, said: "We've been impressed by the innovative solution Costain has brought to what is a complex project. The upgrades at Crewe will enhance treatment performance and help make the site more resilient for customers as demand grows."

Tony Slater continues: "Through our Enterprise model, we're working with delivery partners that have a strong track record of delivering best-in-class water infrastructure solutions, supporting our ambitious plans to transform infrastructure and services across the North West."

The Crewe WwTW improvements are expected to support healthier conditions in the nearby River Weaver and build resilience for projected population growth. The work contributes to United Utilities' £13bn Big North West Upgrade, which will deliver new assets, improve water quality, replace ageing pipes and reduce leakage through to 2030.