KIENBERG Wastewater Treatment Plant, Kienberg, Solothurn, Switzerland

The KIENBERG wastewater treatment plant is located in Kienberg, a municipality in the Bezirk Gösgen district of Solothurn canton, Switzerland. The plant serves a small population of 420 residents and operates under Swiss federal water protection regulations, which require appropriate treatment for all discharges into water bodies. The plant provides secondary treatment, a standard level for small agglomerations in Switzerland. With a designed capacity of 810 m³/day and a current discharge volume of 190.65 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. Swiss regulations under the Waters Protection Act (GSchG) mandate that treatment plants meet strict effluent standards to protect receiving waters. The treated effluent is discharged into a local watercourse that ultimately drains into the Rhine River basin. The Rhine is one of Europe's major rivers, supporting diverse aquatic ecosystems and providing drinking water for millions. The plant's secondary treatment helps reduce organic pollutants and nutrients, contributing to the ecological health of the downstream environment.

The KIENBERG plant discharges into a small stream that flows into the Ergolz River, a tributary of the Rhine. The Rhine basin is ecologically significant, hosting diverse fish species such as salmon and grayling, and supporting migratory birds. The plant's secondary treatment helps maintain water quality in this sensitive watershed, which is important for both biodiversity and downstream water uses.