Myrsöns wetlands - cleaning verdure

An artificial wetland was built in the spring of 2006 next to the lake Myrsjön in Nacka. The aim is to use nature’s own mechanisms to clean the polluted storm water from an industrial area, before it runs into the lake Myrsjön.

An artificial wetland was built in the spring of 2006 next to the lake Myrsjön in Nacka. The purpose is using nature’s own mechanisms to clean the storm water from an industrial area, before it runs into the lake Myrsjön. Tests showed that Myrsjön and its sediment contained high contents of heavy metals and oils. Pollution of oil and metals have also been found in samples, collected from the storm water. The storm water is running to the lake through a storm water conduit, in the western bay, near the industrial area of Kummelberget. In order to control pollution, the old storm water conduit has been replaced by an artificial wetland where the storm water winds its way through the so-called Myrsjö-skärret, before it runs into the lake. Firstly, the water passes through a sedimentation dam, where particles are precipitating to the bottom.The water is then passed through a meandering ditch, where oil and other impurities are filtered off, to a polishing pond. Shortly before the water enters the polishing pond, the remaining oil residue is separated thanks to the fact that the outlet is below the lowest low tide level. Through oxidation, organic pollutants are broken down.