Updated irreducible concentrations in StormTac database and in StormTac Web
The values affect the maximum treatment effect that can be achieved by stopping the treatment when these minimum levels are reached. The difficulty in achieving lower levels is due to e.g. the decomposition of plants, sedimentation due to high flows and that vegetation beds (soil) and filters contain materials that can leak nutrients and pollutants. You can test different facilities and combinations of facilities with different irreducible concentrations if lower outlet concentrations are required.
The update is a result of a comprehensive investigation and literature review and the preparation of a reviewed paper for presentation at the International Conference UDM, Palermo, 24-26 September, 2018. However, further investigation will take place in August-September 2018 by developing flow-weighted outlet concentrations for a large number of facilities in the BMP Database, after which a new update of the irreducible concentrations will be made.