Yorkshire Water’s adoption of Xylem’s CoMag ballasted clarification system at its Knostrop wastewater treatment works (WwTW) marks a significant shift in the water sector’s approach to phosphorus removal. This development, driven by the UK Environment Agency’s Water Industry National Environment Programme (WINEP), could reshape how treatment plants tackle nutrient discharge and manage operational efficiency.
The Knostrop site, serving nearly a million people, faced stringent new phosphorus limits to protect the River Aire and its sensitive ecosystems. The installation of the CoMag system, which uses magnetite to accelerate solid settlement, has not only met but exceeded the required phosphorus levels, achieving an average of 0.25mg/l total phosphorus. This performance underscores the potential of advanced treatment technologies to deliver superior environmental outcomes while optimizing space and resources.
The CoMag system’s ability to process significant treatment flows with a smaller footprint—using just 804m2 compared to the 14,136m2 required by traditional methods—challenges conventional wisdom about the trade-offs between treatment capacity and land use. This innovation could prompt other treatment plants to reconsider their infrastructure investments, particularly as urban populations grow and environmental regulations tighten.
Moreover, the system’s sustainability features, such as the continuous recovery of magnetite, align with the water sector’s increasing focus on circular economy principles. As Sam Akeroyd, capital delivery programme manager at Yorkshire Water, noted, the technology supports both environmental commitments and operational objectives, offering a compelling case for wider adoption.
The success at Knostrop is likely to inspire similar projects, particularly as Yorkshire Water has already selected CoMag for another large site. This trend could accelerate the sector’s shift toward more efficient, compact, and sustainable treatment solutions. However, it also raises questions about the scalability of such technologies and their long-term cost-effectiveness. As the sector grapples with these challenges, the Knostrop project serves as a powerful example of how innovation can drive progress in water treatment and environmental protection.