Sur Wastewater Treatment Plant, Surses, Graubünden, Switzerland

The Sur wastewater treatment plant is located in the municipality of Surses, in the canton of Graubünden, Switzerland. This small-scale facility serves a population of 85, reflecting the rural alpine character of the region. The plant is situated in the village of Sur, part of the Surses valley, and operates as a key component of local sanitation infrastructure. The plant provides secondary treatment, which is the standard biological treatment stage required under Swiss wastewater regulations. Swiss law, aligned with the EU Urban Waste Water Treatment Directive, mandates secondary treatment for agglomerations of this size. The plant has a designed capacity of 200 m³/day and currently discharges an average of 38.58 m³/day, indicating ample reserve capacity for future growth or seasonal variations. The treated effluent is discharged into local watercourses that drain into the Albula River, a tributary of the Rhine. The Rhine ultimately flows into the North Sea. The plant's operation helps protect the sensitive alpine aquatic ecosystems, including the Albula River, which supports diverse fish populations and is part of a region known for its natural beauty and ecological importance.

The plant discharges into small streams that feed the Albula River, a major tributary of the Rhine. The Rhine basin is a transboundary river system flowing through Switzerland, Germany, and the Netherlands into the North Sea. The alpine watershed is ecologically sensitive, supporting cold-water fish species and providing habitat for diverse aquatic life. The plant's secondary treatment helps maintain water quality in this pristine mountain environment.