BELLEVILLE SUR VIE La Mercerie Wastewater Treatment Plant, Bellevigny, France

BELLEVILLE SUR VIE La Mercerie is a wastewater treatment plant located in Bellevigny, in the Pays de la Loire region of western France. The plant serves a population of 4,450 and has a designed capacity of 4,000 cubic meters per day, with an average discharge volume of 793.87 m³/day. It is situated inland, more than 10 km from the coast but within 50 km of the Atlantic Ocean. 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. As a French facility, it operates under national regulations transposing the EU directive, with permits issued by the local water agency (Agence de l'Eau). The treated effluent is discharged into local watercourses that eventually flow into the Atlantic Ocean via the Vendée River or its tributaries. The plant plays a key role in protecting the region's aquatic ecosystems, including the Marais Poitevin wetlands and coastal waters, from nutrient pollution and other contaminants.

The plant discharges into the local watershed of the Vendée River, which flows into the Bay of Biscay in the Atlantic Ocean. The downstream environment includes the Marais Poitevin, a large wetland area that supports diverse aquatic life and serves as an important migratory corridor for birds. Advanced treatment helps reduce nutrient loads that could otherwise contribute to eutrophication in coastal waters.