SAONE Wastewater Treatment Plant, Saône, Bourgogne-Franche-Comté, France

The SAONE wastewater treatment plant is located in the commune of Saône, near Besançon in the Doubs department of Bourgogne-Franche-Comté, France. It serves a population of approximately 4,000 people, classifying it as a small agglomeration under French and EU regulations. The plant provides secondary treatment, which is the minimum standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for freshwater discharges from agglomerations of this size. Its designed capacity is 5,500 m³/day, with an average daily discharge volume of 713.59 m³/day, indicating significant spare capacity. The treated effluent is discharged into the local watershed, which ultimately drains into the Doubs River, a tributary of the Saône River, and then into the Rhône River before reaching the Mediterranean Sea. The plant plays a key role in protecting the water quality of the Doubs River and downstream ecosystems.

The plant discharges into the Doubs River basin, which flows through the Jura region and joins the Saône River near Verdun-sur-le-Doubs. The Saône then flows into the Rhône, which empties into the Mediterranean Sea. The Doubs River supports diverse aquatic life, including fish species such as grayling and brown trout, and its water quality is important for both ecological health and downstream uses.