Treatment performance of a multistage constructed wetland at 69° north, Norway

Fagernes, the only constructed wetland for wastewater treatment in the north of Norway, is located in the municipality of Lenvik. Despite the challenges presented by a cold climate the wetland has been operating well, and chemical and microbiological analyses shows that treatment efficiencies are high. This is particularly the case for COD and phosphorus. Total treatment efficiency for Tot‐N was very high (78%) in comparison with Haugstein, a similar wetland system in southern Norway. In Fagernes, a vertical flow pre‐treatment filter with light‐weight aggregates (Filtralite) aerates the wastewater, stimulates nitrification and binds phosphorus. Both horizontal subsurface flow wetlands (with sand and with light‐weight aggregates) have high phosphorous removal rates.