SION_CHANDOLINE Wastewater Treatment Plant, Sion, Valais/Wallis, Switzerland

SION_CHANDOLINE is a wastewater treatment plant located in the industrial zone of Chandoline, Sion, in the Valais/Wallis canton of Switzerland. The plant serves a population of around 21,685, classifying it as a medium-sized agglomeration under Swiss water management standards. Its location in the Rhone valley places it within a region known for alpine hydrology and intensive agriculture. Switzerland enforces stringent wastewater treatment standards under the Federal Water Protection Act (Gewässerschutzgesetz), which mandates secondary treatment for all municipal plants and tertiary treatment in sensitive areas. For a plant of this scale, typical processes include mechanical screening, biological treatment, and phosphorus removal to protect receiving waters. The plant's discharge is regulated by cantonal authorities, ensuring compliance with national limits for organic matter, nutrients, and micropollutants. The treated effluent from SION_CHANDOLINE ultimately flows into the Rhone River, which drains southwest through Lake Geneva and into the Mediterranean Sea via the Camargue delta. The Rhone basin supports diverse aquatic ecosystems, including fish species such as brown trout and grayling, and is an important migratory corridor for birds. The plant's operation helps maintain water quality in this ecologically sensitive alpine river system.

SION_CHANDOLINE discharges into the Rhone River, which flows through the Valais valley, then into Lake Geneva, and eventually to the Mediterranean Sea. The Rhone basin in Switzerland supports cold-water fish habitats and is a key corridor for migratory birds. The plant's nutrient removal helps prevent eutrophication in downstream lakes and coastal zones.