Villers-le-Lac Wastewater Treatment Plant, Bourgogne-Franche-Comté

The Villers-le-Lac wastewater treatment plant is located in the commune of Villers-le-Lac, in the Doubs department of Bourgogne-Franche-Comté, France. It serves a population of approximately 4,200 residents, placing it in the small-to-medium agglomeration category under French regulations. 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. Its designed capacity is 5,667 m³/day, with an actual discharge volume of 749.27 m³/day, indicating ample reserve capacity. The treated effluent is discharged into the local watershed, which ultimately drains into the Doubs River, a tributary of the Saône, then the Rhône, and finally the Mediterranean Sea. The plant's advanced treatment helps protect the sensitive aquatic ecosystems of the Doubs River and downstream water bodies.

The plant discharges into the Doubs River basin, which flows through the Jura Mountains and joins the Saône River near Verdun-sur-le-Doubs. The Saône then meets the Rhône at Lyon, which empties into the Mediterranean Sea. The Doubs River supports diverse aquatic life and is an important migratory corridor for fish species. Advanced treatment at this plant reduces nutrient loading and protects downstream water quality in this ecologically sensitive region.