Montignac Wastewater Treatment Plant, Montignac-Lascaux, Nouvelle-Aquitaine, France

The Montignac wastewater treatment plant is located in Montignac-Lascaux, in the Dordogne department of Nouvelle-Aquitaine, France. It serves a population of approximately 3,440 residents, making it a small agglomeration under French and EU classifications. The plant is situated near the Vézère River, a tributary of the Dordogne River, which ultimately flows into the Atlantic Ocean via the Gironde estuary. 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 has a designed capacity of 4,167 m³/day and currently discharges an average of 613.69 m³/day, indicating significant spare capacity for future growth. The treated effluent is discharged into the Vézère River, which flows through the Dordogne Valley, a region known for its prehistoric sites and rich biodiversity. The Vézère is a key tributary of the Dordogne River, supporting diverse aquatic life and providing water for agriculture and recreation. The plant's advanced treatment helps maintain water quality in this ecologically sensitive area, which is part of the larger Dordogne basin that drains into the Atlantic Ocean.

The plant discharges into the Vézère River, a tributary of the Dordogne River, which flows into the Gironde estuary and the Atlantic Ocean. The Vézère watershed supports diverse aquatic ecosystems, including fish species such as salmon and trout. The region is also known for its karst geology, which can make groundwater vulnerable to contamination, highlighting the importance of advanced treatment to protect both surface and groundwater quality.