SCHOENENBERG Wastewater Treatment Plant, Wädenswil, Zürich, Switzerland

SCHOENENBERG is an advanced wastewater treatment plant located in Schönenberg, Wädenswil, in the canton of Zürich, Switzerland. The plant serves a population of approximately 1,956 residents, reflecting its role in managing municipal wastewater for a small community in the Zurich region. As an advanced treatment facility, SCHOENENBERG goes beyond secondary treatment to remove nutrients such as nitrogen and phosphorus, ensuring high-quality effluent. The plant has a designed capacity of 4,100 cubic meters per day and currently discharges about 888 cubic meters daily, indicating ample reserve capacity. Swiss wastewater treatment plants operate under the Swiss Water Protection Act (Gewässerschutzgesetz), which mandates strict effluent standards to protect sensitive water bodies. The treated effluent from SCHOENENBERG is discharged into local streams that flow into Lake Zurich, a major freshwater lake and source of drinking water for the region. The plant's advanced treatment helps safeguard the lake's water quality and supports the diverse aquatic ecosystem, including fish species and migratory birds.

The plant discharges into small watercourses that drain into Lake Zurich, a large pre-alpine lake in northern Switzerland. Lake Zurich is a critical drinking water reservoir and supports recreational activities and biodiversity. The advanced treatment at SCHOENENBERG reduces nutrient loading, helping to prevent eutrophication and maintain the lake's ecological balance. The lake ultimately drains via the Limmat River into the Aare and then the Rhine, connecting to the North Sea.