MOUTHE Wastewater Treatment Plant, Les Villedieu, Bourgogne-Franche-Comté

The MOUTHE wastewater treatment plant is located in Les Villedieu, within the Bourgogne-Franche-Comté region of eastern France. It serves a population of approximately 3,950, classifying it as a small to medium agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD). The plant is situated inland, near the Jura mountains, and its operations are part of France's national water management framework. The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU UWWTD for agglomerations of this size. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) to protect sensitive water bodies. The designed capacity is 3,500 m³/day, and the current discharge volume is 704.67 m³/day, indicating operational headroom. The treated effluent is discharged into local watercourses that eventually feed into the Doubs River, a tributary of the Saône, which flows into the Rhône and ultimately the Mediterranean Sea. The surrounding watershed supports diverse aquatic life and is part of a region known for its karstic geology and sensitive groundwater systems. The plant's advanced treatment helps protect downstream ecosystems from eutrophication and other pollution impacts.

The MOUTHE plant discharges into local streams that drain into the Doubs River, a major tributary of the Saône River, which flows into the Rhône and then the Mediterranean Sea. The watershed is characterized by karstic geology, making groundwater particularly vulnerable to contamination. The region supports diverse aquatic habitats, including fish species such as brown trout and grayling. Advanced treatment at the plant reduces nutrient loads, helping to prevent algal blooms and maintain water quality in downstream rivers and the Mediterranean coastal zone.