In June 2017, the engineering company WEREC, specialised in water ecosystem recovery and stormwater management, installed a new stormwater filtration system in the city of Örebro, Sweden, on behalf of the local municipality. The project was part of the city’s broader effort to improve water quality and reduce nutrient pollution from urban runoff before it reaches nearby water bodies.
The solution consists of a two-stage filtration system. The first stage is a pre-filter designed to separate and capture oils and fats from stormwater, significantly reducing the load of hydrocarbons and coarse contaminants. Following this initial treatment, the water flows into the main filter, which is filled with Filtralite® Nature P — a lightweight expanded clay aggregate known for its excellent filtration properties and high phosphorus adsorption capacity.
Thanks to its porous structure and large specific surface area, Filtralite® Nature P effectively traps suspended solids while simultaneously binding dissolved phosphorus. This dual function is crucial in stormwater treatment, where phosphorus from urban surfaces contributes to eutrophication in lakes and rivers, leading to harmful algal blooms and ecosystem degradation.
Another advantage of Filtralite® Nature P is its long lifespan and easy maintenance. The filter media is expected to last for up to 10 years before replacement is needed, offering municipalities a low-maintenance and cost-effective solution. When the time comes, the material can be easily removed and replaced, minimising operational downtime.
The Örebro project demonstrates how Filtralite® Nature P stormwater filters can help municipalities meet stricter water quality standards and improve the ecological health of receiving water bodies. By combining efficient particle removal with phosphorus retention, the system contributes to cleaner urban runoff and supports the city’s long-term water management and sustainability goals.
