HUNDWILSCHMITTE Wastewater Treatment Plant, Hundwil, Switzerland

HUNDWILSCHMITTE is a municipal wastewater treatment plant located in Hundwil, a village in the canton of Appenzell Ausserrhoden, Switzerland. The facility serves a small population of 517 residents, reflecting its role in a rural alpine community. The plant is situated in the Hinterland region, characterized by rolling hills and agricultural landscapes. The plant provides secondary treatment, which is the standard biological treatment stage required under Swiss water protection legislation. Swiss regulations, aligned with the EU Urban Waste Water Treatment Directive, mandate secondary treatment for agglomerations of this size. The plant has a designed capacity of 800 m³/day and currently discharges 234.68 m³/day, indicating operational headroom for future growth or seasonal variations. The treated effluent is discharged into local watercourses that drain into the Sitter River, a tributary of the Thur River, which ultimately flows into the Rhine River and then the North Sea. The plant plays a key role in protecting the sensitive alpine watershed, supporting aquatic life and downstream water quality in the Rhine basin.

The plant discharges into small streams that feed the Sitter River, part of the Thur-Rhine system, which flows through northeastern Switzerland before reaching the North Sea. The local watershed supports diverse aquatic ecosystems, including brown trout and other cold-water species. The alpine terrain and agricultural land use make nutrient management critical to prevent eutrophication in downstream lakes and rivers.