Kappalaverket Wastewater Treatment Plant, Stockholm County, Sweden

Kappalaverket is a large wastewater treatment plant located on Lidingö in Stockholm County, Sweden. It serves a population equivalent of over 570,000, making it one of the largest treatment facilities in the region. The plant is operated by the municipal association Käppalaförbundet and plays a critical role in managing wastewater from the northeastern parts of the Stockholm metropolitan area. The plant is designed with a capacity of 1.00 (likely in cubic meters per second or similar unit), reflecting its scale. As a Swedish facility, it operates under the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates advanced treatment for large agglomerations discharging into sensitive areas. The Baltic Sea is designated as a sensitive area under the directive, requiring nutrient removal to combat eutrophication. Treated effluent from Kappalaverket is discharged into the Baltic Sea via the Stockholm archipelago. The receiving waters are part of the Baltic Sea, a brackish inland sea with limited water exchange, making it highly sensitive to nutrient pollution. The plant's advanced treatment helps protect the archipelago's diverse marine life and supports recreational and ecological values.

Kappalaverket discharges into the Stockholm archipelago, which connects to the Baltic Sea. The Baltic Sea is a semi-enclosed brackish sea with a long residence time, making it vulnerable to eutrophication from nutrient inputs. The archipelago supports diverse aquatic life, including fish, seabirds, and unique flora, and is an important recreational area for the region.