ALBERTVILLE Gilly Wastewater Treatment Plant, Gilly-sur-Isère, France

The ALBERTVILLE Gilly wastewater treatment plant is located in Gilly-sur-Isère, a commune in the Savoie department of the Auvergne-Rhône-Alpes region, France. Serving a population of around 40,000, the plant is part of the municipal infrastructure for the Albertville area. The facility is situated near the Isère River, which flows through the Alpine valley. As a plant serving over 15,000 population equivalent, it falls under the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment as a minimum. For agglomerations of this size in sensitive areas, tertiary treatment may be mandated to reduce nutrient loads. The plant's design and operation are subject to French national regulations transposing the directive, with oversight from the local water agency (Agence de l'Eau). The treated effluent is discharged into the Isère River, a major tributary of the Rhône. The Isère flows through the Tarentaise Valley and joins the Rhône near Valence. The Rhône then continues to the Mediterranean Sea. The Alpine watershed supports diverse aquatic life and is important for regional biodiversity, including fish species such as brown trout and grayling.

The plant discharges into the Isère River, which flows through the Savoie region and joins the Rhône River near Valence. The Rhône ultimately reaches the Mediterranean Sea. The Isère watershed in the Alps supports sensitive aquatic ecosystems, including cold-water fish habitats. The river's flow regime is influenced by snowmelt and glacial runoff, making it ecologically significant for migratory species and overall biodiversity in the region.