Mortagne-sur-Sèvre Evrunes Gazeau Wastewater Treatment Plant, Evrunes, France

The Mortagne-sur-Sèvre Evrunes Gazeau wastewater treatment plant is located in Evrunes, a commune within Mortagne-sur-Sèvre in the Pays de la Loire region of western France. It serves a population of 4,250, placing it in the small-to-medium agglomeration category under French and EU regulations. The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Its designed capacity is 7,200 m³/day, with an average daily discharge of 758.19 m³, indicating significant reserve capacity. The facility operates under the French regulatory framework, which implements the EU directive through national legislation and permits issued by local authorities. The treated effluent is discharged into the local watershed, which ultimately drains into the Sèvre Nantaise river and then the Loire River, one of France's major waterways. The Loire estuary flows into the Atlantic Ocean, supporting diverse aquatic ecosystems and migratory fish species. The plant's advanced treatment helps protect these downstream environments from nutrient pollution and other contaminants.

The plant discharges into the Sèvre Nantaise river basin, a tributary of the Loire River. The Loire is France's longest river and its estuary is a critical habitat for migratory fish such as Atlantic salmon and European eel. The advanced treatment level reduces nutrient loads, helping to prevent eutrophication in the Loire estuary and coastal waters of the Bay of Biscay.