Vaz/Obervaz Canius Wastewater Treatment Plant, Graubünden, Switzerland

The Vaz/Obervaz Canius wastewater treatment plant is located in the municipality of Vaz/Obervaz in the canton of Graubünden, Switzerland. Situated in the Alpine region at an elevation of around 1,200 meters, the plant serves a population of approximately 9,200 people, classifying it as a medium-sized agglomeration under Swiss water protection standards. As a Swiss wastewater facility, the plant is subject to the Federal Water Protection Act (Gewässerschutzgesetz), which mandates advanced treatment to protect sensitive Alpine water bodies. For agglomerations of this size, secondary treatment with nutrient removal is typically required, especially in areas where receiving waters flow into ecologically valuable lakes or rivers. The treated effluent from the plant is discharged into the local watershed, which ultimately drains into the Rhine River via the Albula and Hinterrhein tributaries. The Alpine environment is particularly sensitive to nutrient pollution, and the plant plays a crucial role in maintaining water quality in this region, which supports diverse aquatic life and serves as a source for downstream drinking water.

The plant discharges into the Alpine watershed of the Albula River, a tributary of the Hinterrhein, which flows into the Rhine River and eventually the North Sea. This high-altitude catchment is ecologically sensitive, supporting cold-water fish species and pristine aquatic habitats. Nutrient loading from wastewater must be carefully managed to prevent eutrophication in downstream lakes and rivers.