GENEST SAINT ISLE Wastewater Treatment Plant, Le Genest-Saint-Isle, France

GENEST SAINT ISLE is a wastewater treatment plant located in Le Genest-Saint-Isle, a commune in the Mayenne department of Pays de la Loire, France. The facility serves a population of approximately 1,276 residents, placing it in the small agglomeration category under French and EU regulations. The plant operates with 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 2,500 m³/day, with a reported discharge volume of 227.64 m³/day, indicating operational headroom. The facility is situated inland, more than 50 km from the coast. The treated effluent is discharged into the local watershed, which ultimately drains into the Mayenne River, a tributary of the Loire River. The Loire basin is one of France's major river systems, supporting diverse aquatic ecosystems and agricultural activities. The advanced treatment level helps protect downstream water quality in this sensitive region.

The plant discharges into the Mayenne River basin, which flows into the Loire River and eventually reaches the Atlantic Ocean. The Loire is a major European river known for its biodiversity, including migratory fish species such as Atlantic salmon and European eel. Advanced treatment at this plant reduces nutrient loading, helping to prevent eutrophication in downstream waters and supporting the ecological health of the Loire estuary.