Eschenbach Wastewater Treatment Plant, Eschenbach (SG), St. Gallen, Switzerland

Eschenbach wastewater treatment plant is located in Eschenbach (SG), a municipality in the Wahlkreis See-Gaster district of St. Gallen, Switzerland. The plant serves a population of approximately 9,549 residents, placing it in the small-to-medium agglomeration category. Its location near the shore of Lake Zurich makes it a coastal plant within 10 km of the lake. Swiss wastewater treatment plants are regulated under the Federal Water Protection Act (Gewässerschutzgesetz), which mandates advanced treatment for discharges into sensitive water bodies. For plants of this scale, secondary treatment with nutrient removal is typically required to protect receiving waters. The plant's designed capacity is 1.00 (likely in thousands of cubic meters per day), indicating it is sized for its service population. The plant discharges treated wastewater into the local watershed that drains into Lake Zurich, a large pre-alpine lake. Lake Zurich is an important drinking water reservoir and recreational area, supporting diverse aquatic life. The lake's outflow, the Limmat River, flows through Zurich and eventually joins the Aare and Rhine rivers, reaching the North Sea. Protecting water quality in this system is critical for both ecological health and human use.

The plant discharges into the catchment of Lake Zurich, a deep, oligotrophic pre-alpine lake that serves as a major drinking water source for the region. The lake supports a diverse ecosystem including whitefish, perch, and Arctic char. Its outflow, the Limmat River, flows through Zurich and joins the Aare and Rhine rivers, ultimately reaching the North Sea. Nutrient loading from wastewater can contribute to algal blooms, so advanced treatment is essential to maintain the lake's high water quality.