A northern constructed wetland for treatment of wastewater

In the Swedish mountain area, at about 63 degr. north, a small constructed wetland, consisting of three biological dams (25x25 m) was constructed in 1991.The plant is situated in an agricultural area near the lake Storsjon, Jamtland county. The plant serves about 100 persons. The first dam in the constructed wetland is S-formed, about 3 m deep with a combined anaerobic and aerobic treatment. The second stage is a vegetated (Carex sp), rather shallow dam (0,4 m) and the third dam is about 2 m. deep and equipped with a few islets. In the third dam, waterfowls are breeding each summer. Around the constructed wetland, trees has been planted and in the wetland the hardy species crucian carp (Carassius carassius) has been introduced in summer 1994 in order to extend the food-web. The constructed wetland is not yet fully established. Consequently, especially in winter, the microbial community and the plants are not able to take up mineralized nutrients. However, in summer, the constructed wetland meets the requirements. This experiment is during the summer of 1995 being extended with an surface flow system. The effluent is meandering through a small wooded (Salix sp.) area in which the nutrients are to be absorbed. The constructed wetland plant at Mansasen, Are municipality, Jamtland county, Sweden is an experiment in which a wetland system is combined with a terrestrial system.