EPESSES Les Trois Chenes Wastewater Treatment Plant, Les Épesses, France

EPESSES Les Trois Chenes is an advanced wastewater treatment plant located in Les Épesses, a commune in the Vendée department of Pays de la Loire, France. The plant serves a population of approximately 4,167 people, placing it in the small agglomeration category under French and EU regulations. Its designed capacity is 2,500 m³/day, with a reported discharge volume of 743.39 m³/day. As an advanced treatment facility, EPESSES Les Trois Chenes goes beyond secondary treatment to remove nutrients and other pollutants, meeting stringent standards under the EU Urban Waste Water Treatment Directive (91/271/EEC). For agglomerations of this size, the directive requires secondary treatment, but the plant's advanced level indicates it likely operates in a sensitive area or meets higher local requirements. The plant discharges treated wastewater into the local watershed, which ultimately drains into the Atlantic Ocean via the Vendée River and the Bay of Biscay. The region's rivers support diverse aquatic life and are important for agriculture and tourism. By providing advanced treatment, the plant helps protect downstream water quality and ecosystems.

The plant's treated effluent enters the local river network, which flows into the Vendée River and eventually reaches the Bay of Biscay on the Atlantic coast. This watershed supports a mix of agricultural and natural landscapes, with rivers providing habitat for fish and migratory birds. Advanced treatment reduces nutrient loads, helping to prevent eutrophication in downstream coastal waters.