Eydoche Wastewater Treatment Plant - Secondary Treatment in Auvergne-Rhône-Alpes

The Eydoche wastewater treatment plant is located in the commune of Eydoche, within the Isère department of the Auvergne-Rhône-Alpes region in southeastern France. It serves a population of approximately 2,380 residents, classifying it as a small agglomeration under French and EU regulations. The plant is situated inland, away from coastal areas, and its operations are part of the regional water management infrastructure. The plant employs secondary treatment, which is the standard biological treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a designed capacity of 2,150 m³ per day and a current discharge volume of 424.59 m³ per day, the plant operates well below its capacity, indicating room for future growth or seasonal variations. The treatment process ensures that effluent meets regulatory standards before discharge. The treated wastewater is discharged into local watercourses that ultimately drain into the Rhône River basin, a major European river flowing into the Mediterranean Sea. The plant plays a key role in protecting the local watershed and downstream ecosystems, including the Rhône delta and the Gulf of Lion, by reducing nutrient and pollutant loads.

The plant discharges into small streams that feed into the Bourbre River, a tributary of the Rhône River. The Rhône flows through the Camargue region before reaching the Mediterranean Sea. This watershed supports diverse aquatic life and is an important migratory corridor for fish species. The plant's secondary treatment helps control nutrient pollution, which is critical for preventing eutrophication in downstream water bodies.