Quarten Mittensee Wastewater Treatment Plant, St. Gallen, Switzerland

Quarten Mittensee is a municipal wastewater treatment plant located in the village of Quarten, within the Wahlkreis Sarganserland district of St. Gallen, Switzerland. The facility serves a population of about 4,938 residents, reflecting a small to medium-sized agglomeration typical of Alpine communities in the region. As a Swiss wastewater treatment plant, Quarten Mittensee operates under the Swiss Water Protection Act (Gewässerschutzgesetz), which mandates advanced treatment standards for all discharges into sensitive water bodies. For plants serving populations of this scale, secondary treatment with nutrient removal is generally required to protect the receiving waters, which are often tributaries of major river systems. The treated effluent from Quarten Mittensee is discharged into local waterways that ultimately drain into Lake Walen (Walensee), a deep Alpine lake known for its high water quality and ecological significance. The lake supports diverse aquatic life and is an important recreational resource. The plant's operation helps maintain the ecological balance of the lake and its downstream connection to the Linth River and eventually Lake Zurich.

The plant discharges into local streams that flow into Lake Walen (Walensee), a deep Alpine lake in eastern Switzerland. The lake is part of the Rhine basin, with its outflow feeding the Linth River, which eventually reaches Lake Zurich and the Rhine River. The watershed supports sensitive aquatic ecosystems, including cold-water fish species and oligotrophic conditions that require careful nutrient management to prevent eutrophication.