Stäfa-Oetikon Wastewater Treatment Plant, Stäfa, Zürich, Switzerland

The Stäfa-Oetikon wastewater treatment plant (STAEFA_OETIKON) is located in Stäfa, a municipality in the canton of Zürich, Switzerland, on the northern shore of Lake Zurich. The plant serves a population of approximately 9,825 residents, classifying it as a small to medium agglomeration under Swiss water protection regulations. As a Swiss wastewater facility, the plant operates under the Swiss Water Protection Act (Gewässerschutzgesetz), which mandates strict treatment standards for discharges into sensitive water bodies like Lake Zurich. The designed capacity is 1.00 (likely in thousands of cubic meters per day or similar unit), indicating a modest scale. Swiss regulations typically require at least secondary treatment with phosphorus removal for plants discharging into lakes to prevent eutrophication. The plant's treated effluent is discharged into Lake Zurich, which is part of the Rhine basin via the Limmat River. Lake Zurich is a deep, oligotrophic to mesotrophic lake that serves as a drinking water source and supports diverse aquatic life. The plant's proximity to the lake (within 10 km of the coast, i.e., lakeshore) underscores the importance of advanced treatment to protect water quality.

The plant discharges into Lake Zurich, a large Alpine lake that drains via the Limmat River into the Rhine River and ultimately the North Sea. Lake Zurich is a critical drinking water reservoir and supports a sensitive aquatic ecosystem, including fish species like whitefish and perch. Nutrient loading from wastewater must be carefully controlled to prevent algal blooms and maintain water clarity.