Lumnezia Vrin Wastewater Treatment Plant, Lumnezia, Graubünden

Lumnezia Vrin is a municipal wastewater treatment plant located in the village of Vrin, part of the Lumnezia valley in the canton of Graubünden, Switzerland. The plant serves a small population of 374 residents and operates with a designed capacity of 875 m³/day, currently discharging 169.77 m³/day of treated effluent. The plant provides secondary treatment, which is the standard biological treatment required under Swiss water protection legislation. For small alpine communities like Lumnezia, secondary treatment effectively reduces organic pollutants and suspended solids, ensuring compliance with national water quality standards. The treated effluent is discharged into the local stream system within the Vorderrhein basin, which flows into the Rhine River and eventually to the North Sea. The plant plays a key role in protecting the sensitive alpine aquatic ecosystems of the Lumnezia valley, which support diverse macroinvertebrate communities and serve as a habitat for brown trout.

The plant discharges into a tributary of the Vorderrhein (Anterior Rhine), which joins the Hinterrhein to form the Rhine River. The Rhine flows through Lake Constance and ultimately reaches the North Sea. The Lumnezia valley is an ecologically sensitive alpine region with cold, oxygen-rich waters that support brown trout and other cold-water species. The plant's secondary treatment helps maintain water quality in this fragile environment.