UNTERBAECH Wastewater Treatment Plant, Unterbäch, Valais, Switzerland

UNTERBAECH is a wastewater treatment plant located in Unterbäch, a municipality in the Valais/Wallis canton of Switzerland. The plant serves a population of 604 and is situated in the alpine region of the Rhone valley, an area known for its mountainous terrain and glacial rivers. As a facility in a small agglomeration, it plays a key role in protecting local water quality in a region where tourism and agriculture are prominent. The plant employs advanced treatment processes, which go beyond secondary treatment to remove nutrients and other pollutants. This level of treatment is typical for Swiss plants discharging into sensitive water bodies, in line with the Swiss Water Protection Act (Gewässerschutzgesetz). The designed capacity is 3,750 cubic meters per day, with a current discharge volume of 274.17 cubic meters per day, indicating ample reserve capacity for future growth or seasonal peaks. The treated effluent is discharged into the local watershed, which ultimately drains into the Rhone River. The Rhone flows through the Valais valley and into Lake Geneva (Lac Léman), a major freshwater lake that supports diverse aquatic life and provides drinking water for millions. The advanced treatment at UNTERBAECH helps minimize nutrient loading and protects the ecological health of the Rhone and Lake Geneva.

The plant discharges into the Rhone River basin, which flows through the Swiss Alps and into Lake Geneva. Lake Geneva is a large, deep lake that supports a variety of fish species and is an important migratory corridor for birds. The advanced treatment at UNTERBAECH reduces phosphorus and nitrogen inputs, helping to prevent eutrophication in the lake and maintain water quality for downstream communities and ecosystems.