SAIN BEL Wastewater Treatment Plant, Sain-Bel, Auvergne-Rhône-Alpes, France

The SAIN BEL wastewater treatment plant is located in the commune of Sain-Bel, within the Rhône department of the Auvergne-Rhône-Alpes region in eastern France. The facility serves a population of approximately 3,498 residents and is designed with a capacity of 3,500 m³ per day, indicating it is sized to meet the needs of this small agglomeration. The plant employs advanced treatment processes, which go beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) to protect sensitive receiving waters. The plant's discharge volume is reported at 624.04 m³/day, reflecting its operational scale. The treated effluent is discharged into the local watershed, which ultimately drains into the Brévenne River, a tributary of the Saône River. The Saône flows into the Rhône River, which empties into the Mediterranean Sea. The advanced treatment level helps safeguard the ecological health of these water bodies, supporting aquatic life and downstream water quality.

The plant discharges into the Brévenne River, which flows into the Saône River, a major tributary of the Rhône River. The Rhône eventually reaches the Mediterranean Sea. The watershed supports diverse aquatic ecosystems, including fish populations and riparian habitats. Advanced treatment at this plant reduces nutrient loads, helping to prevent eutrophication in downstream waters and protecting the ecological balance of the river system.