SCHWYZ Wastewater Treatment Plant, Ingenbohl, Schwyz, Switzerland

The SCHWYZ wastewater treatment plant is located in Ingenbohl, within the canton of Schwyz, Switzerland. It serves a population equivalent of approximately 55,703, classifying it as a medium-to-large agglomeration under Swiss water protection standards. The plant is situated near Lake Lucerne, a major water body in central Switzerland. Swiss wastewater treatment plants are regulated by the Federal Water Protection Act (Gewässerschutzgesetz), which mandates advanced treatment to protect sensitive water bodies. For agglomerations of this scale, tertiary treatment (including phosphorus removal) is typically required to meet stringent effluent quality standards. Swiss regulations ensure high treatment performance. The treated effluent is discharged into the local water system, which ultimately drains into Lake Lucerne (Vierwaldstättersee). Lake Lucerne is a deep, oligotrophic lake that supports diverse aquatic life and serves as a drinking water source for surrounding communities. The plant plays a critical role in maintaining the lake's water quality by removing nutrients and pollutants before discharge.

The plant discharges into the catchment of Lake Lucerne, a large alpine lake in central Switzerland. The lake drains via the Reuss River into the Aare River, then into the Rhine, and eventually to the North Sea. Lake Lucerne is ecologically sensitive due to its oligotrophic status and importance for biodiversity, including fish species like lake trout and Arctic char. Nutrient loading from wastewater must be carefully controlled to prevent eutrophication.