Eskilstuna Avloppsreningsverk - Municipal Wastewater Treatment Plant, Eskilstuna, Sweden

Eskilstuna Avloppsreningsverk is the primary wastewater treatment facility for the city of Eskilstuna, located in Södermanland County, Sweden. The plant serves a population of around 140,900, classifying it as a large agglomeration under EU regulations. Its location near the Eskilstuna River places it within the Norrström drainage basin, which ultimately flows into the Baltic Sea. As a large agglomeration, the plant is required to meet stringent treatment standards under the EU Urban Waste Water Treatment Directive (91/271/EEC). This directive mandates secondary treatment as a minimum, with tertiary treatment required for discharges into sensitive areas. The plant's designed capacity is 1.00 (likely in million cubic meters per year or similar unit), indicating a substantial infrastructure capable of handling the city's wastewater load. The treated effluent is discharged into the Eskilstuna River, which flows into Lake Mälaren, Sweden's third-largest lake. Lake Mälaren is a critical freshwater resource and an ecologically sensitive water body that supports diverse aquatic life and serves as a drinking water source for millions. The plant's performance is therefore vital for protecting water quality in the lake and the downstream Baltic Sea ecosystem.

The plant discharges into the Eskilstuna River, which flows into Lake Mälaren, a large freshwater lake that drains into the Baltic Sea via the Norrström channel. Lake Mälaren is ecologically significant, supporting diverse fish populations and serving as a habitat for migratory birds. The Baltic Sea is a brackish water body with limited water exchange, making it sensitive to nutrient pollution. Effective treatment at Eskilstuna Avloppsreningsverk helps reduce eutrophication risks in this vulnerable marine environment.