SAINT AIGNAN GRANDLIEU Habra - Advanced Wastewater Treatment Plant in Saint-Aignan-Grandlieu, France

SAINT AIGNAN GRANDLIEU Habra is an advanced wastewater treatment facility located in Saint-Aignan-Grandlieu, within the Loire-Atlantique department of the Pays de la Loire region in western France. The plant serves a population of 2,683 and has a designed capacity of 4,000 cubic meters per day, with a current discharge volume of 478.64 cubic meters per day. As an advanced treatment plant, it goes beyond secondary biological treatment to remove nutrients such as nitrogen and phosphorus, which is typical for facilities discharging into sensitive environments. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), France classifies agglomerations above 2,000 population equivalent as requiring collection and treatment, with advanced (tertiary) treatment mandated for discharges into sensitive areas. The plant's treated effluent is discharged into the local watershed, which ultimately drains into the Loire River estuary and the Bay of Biscay. This region supports diverse aquatic life and is important for migratory fish species. The advanced treatment helps protect downstream water quality in the Loire estuary and coastal marine environment.

The plant discharges into the local watershed that feeds the Loire River, one of France's major rivers, which flows into the Bay of Biscay on the Atlantic coast. The Loire estuary is an ecologically sensitive area supporting diverse aquatic life, including migratory fish such as Atlantic salmon and European eel. Advanced treatment at this plant helps reduce nutrient loading that could contribute to eutrophication in the downstream coastal waters.