Chateau Queyras Wastewater Treatment Plant, Château-Ville-Vieille, France

Chateau Queyras is a wastewater treatment plant located in Château-Ville-Vieille, within the Provence-Alpes-Côte d'Azur region of southeastern France. The plant serves a population of approximately 3,750 people and is situated in the mountainous terrain of the Hautes-Alpes department near the Italian border. The plant operates with secondary treatment, which is the standard required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Its designed capacity is 6,900 m³/day, and the current discharge volume is 668.99 m³/day, indicating significant spare capacity. The facility is part of France's national wastewater infrastructure managed under the French Water Agencies. The treated effluent is discharged into the local watershed, which ultimately drains into the Durance River, a major tributary of the Rhône. The Rhône flows into the Mediterranean Sea. The plant's location in a high-altitude alpine environment means it protects sensitive mountain streams and downstream ecosystems from nutrient pollution.

The plant discharges into the local watershed that feeds the Durance River, a key tributary of the Rhône River. The Rhône flows into the Mediterranean Sea, making this plant part of a large transboundary basin. The alpine streams in this region support diverse aquatic life, including native trout species, and are ecologically sensitive due to cold, oligotrophic conditions. Proper treatment helps prevent eutrophication in downstream water bodies.