Himmelried Ostwaldeck Wastewater Treatment Plant, Himmelried, Solothurn, Switzerland

Himmelried Ostwaldeck is a municipal wastewater treatment plant located in Himmelried, a village in the Bezirk Thierstein district of Solothurn, Switzerland. The plant serves a small population of 520 residents, reflecting the rural character of the area. It is situated in the Jura mountain region, which influences local hydrology and treatment requirements. 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 750 m³/day and currently discharges 236.04 m³/day, indicating ample reserve capacity for future growth or seasonal variations. The treated effluent is discharged into local watercourses that drain into the Birs River, a tributary of the Rhine. The Rhine ultimately flows into the North Sea. The plant plays a key role in protecting the sensitive aquatic ecosystems of the Jura streams and the Rhine basin from nutrient pollution and organic loads.

The plant discharges into small streams in the Jura region, which feed into the Birs River and then the Rhine. The Rhine is a major European waterway supporting diverse aquatic life and providing drinking water for millions. The plant's secondary treatment helps reduce organic matter and nutrients, protecting downstream ecosystems from eutrophication and maintaining water quality in this ecologically sensitive area.