Montesquieu-Volvestre Wastewater Treatment Plant, Occitanie, France

The Montesquieu-Volvestre wastewater treatment plant is located in the commune of Montesquieu-Volvestre, in the Haute-Garonne department of Occitanie, southern France. It serves a population of approximately 2,585 residents, classifying it as a small agglomeration under French and EU regulations. The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Its designed capacity is 2,500 m³/day, and it currently treats an average daily flow of 461.16 m³, indicating ample reserve capacity. The treated effluent is discharged into the local watershed, which ultimately drains into the Garonne River via the Arize River. The Garonne flows through southwestern France and into the Gironde estuary, supporting diverse aquatic ecosystems and agricultural water use downstream.

The plant discharges into the Arize River, a tributary of the Garonne River, which flows through the Occitanie region. The Garonne River is a major watercourse that empties into the Gironde estuary on the Atlantic coast. The watershed supports a variety of aquatic life, including migratory fish species such as Atlantic salmon and European eel. The advanced treatment level helps protect water quality in this ecologically sensitive river system.