TREASURE - Treatment and re-use of urban stormwater runoff by innovative technologies for removal of pollutants

Urban run-off water does not usually kill fish directly, but it contributes to an accumulation of pollutants in the food chain, which can have a terrible effect on biodiversity over time. The project aimed to develop and demonstrate cost-effective and efficient technologies for removing dissolved pollutants from stormwater run-off to reduce diffuse urban pollutant loads onto receiving waters at Aarhus, Odense and Silkeborg. To this purpose, it constructed three detention ponds, demonstrating three different treatment processes, designed not only to remove small particles and colloidal and soluble bound pollutants from the surface waters collected from the catchment area, but also as part of the local urban landscape. The ponds were equipped for on-line monitoring of the treatment performance. The most effective treatment process was found to be the wet retention pond with a sand filter and fixed-media absorption filter. The fixed-media absorption technology proved very efficient at managing high loads of dissolved heavy metals. Application is not restricted to any particular urban context and could also be expanded to purposes such as treating contaminated drinking water or phosphorous-polluted surface waters.