MONTSURS 2 Wastewater Treatment Plant, Montsûrs, Pays de la Loire, France

MONTSURS 2 is an advanced wastewater treatment plant located in Montsûrs, a commune in the Mayenne department of the Pays de la Loire region, France. The plant serves a population of approximately 4,550 residents, making it a small to medium agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD). As an advanced treatment facility, MONTSURS 2 goes beyond secondary treatment to remove nutrients such as nitrogen and phosphorus, which is typical for plants discharging into sensitive areas. The plant has a designed capacity of 5,000 m³/day and currently treats an average daily volume of 811.71 m³, indicating significant spare capacity. Under the EU UWWTD, agglomerations of this size are required to provide secondary treatment, but the advanced level suggests the receiving environment may be sensitive or the plant is designed for future growth. The treated effluent is discharged into the local watershed, which ultimately drains into the Mayenne River, a tributary of the Loire River. The Loire River flows into the Atlantic Ocean, and the region is known for its agricultural landscape and biodiversity. The plant's advanced treatment helps protect downstream water quality and supports the ecological health of the Loire basin.

MONTSURS 2 discharges treated wastewater into the Mayenne River basin, which flows into the Loire River and eventually reaches the Atlantic Ocean. The Loire basin is ecologically significant, supporting diverse aquatic life and migratory fish species. The advanced treatment level helps minimize nutrient loading, protecting the river from eutrophication and preserving water quality for downstream communities and ecosystems.