BUEHLERAU Wastewater Treatment Plant, Bühler, Appenzell Ausserrhoden, Switzerland

BUEHLERAU is a wastewater treatment plant located in Bühler, a municipality in the canton of Appenzell Ausserrhoden, Switzerland. Serving a population of approximately 8,108, the plant is part of the region's municipal wastewater infrastructure, situated in the Mittelland area at an elevation typical of the Swiss pre-Alps. As a Swiss plant, BUEHLERAU operates under the Federal Water Protection Act (Gewässerschutzgesetz), which mandates stringent treatment standards. For agglomerations of this size, secondary treatment with nutrient removal is typically required to protect sensitive water bodies. The plant's designed capacity is 1.00 (likely in thousand cubic meters per day or similar unit), indicating a facility scaled to its service population. The treated effluent is discharged into local watercourses that drain into the Rhine basin, ultimately reaching the North Sea. The plant plays a key role in safeguarding the region's streams and rivers, which support diverse aquatic life and are used for recreation and drinking water supply downstream.

The plant discharges into local streams that flow into the Sitter River, a tributary of the Thur River, which joins the Rhine near Schaffhausen. The Rhine then flows through Germany and the Netherlands into the North Sea. The watershed supports sensitive aquatic ecosystems, including fish species such as brown trout and grayling, and the region's water quality is critical for both ecological health and downstream drinking water supplies.