Strategies for Management of Polluted Stormwater from an Urban Highway in Göteborg, Sweden

Abstract

Stormwater from urban highways contains high concentrations of heavy metals, polycyclic aromatic hydrocarbons (PAHs) and other substances that are harmful to the environment. The choice of abatement strategies is not trivial. If the stormwater is brought to the municipal wastewater treatment plant (WWTP) in combined sewers, it will cause overflows at combined sewer overflow (CSO) points, accumulation of contaminated sludge that cannot be used as fertilisers on farmland, and sometimes disturbances of the operation of the WWTP. If the stormwater is discharged to a receiving water it will carry all the pollutants directly to the water body, most often a small urban creek not suitable for such discharges. If the stormwater is allowed to infiltrate, the groundwater and in some cases the vegetation will be effected. In an action plan for the improvement of the stormwater handling all these issues have to be taken into account. Abatement of pollutants at the source is one very important strategy that should have first priority. Thus, to improve the receiving water in a sustainable way the sources of the pollution have to be identified, quantified and reduced.