Senonches Wastewater Treatment Plant: Advanced Treatment in Centre-Val de Loire

The Senonches wastewater treatment plant is located in the commune of Senonches, within the Eure-et-Loir department of the Centre-Val de Loire region in north-central France. The facility serves a population of approximately 4,107 residents and is designed to handle a capacity of 5,000 cubic meters per day, with an average discharge volume of 732.68 m³/day. As an advanced treatment plant, Senonches goes beyond the secondary treatment requirements mandated by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The directive requires secondary treatment for populations above 2,000, and advanced (tertiary) treatment is typically implemented in sensitive areas or where nutrient removal is necessary to protect receiving waters. The plant's treated effluent is discharged into the local watershed, which ultimately drains into the Eure River, a tributary of the Seine. The Seine basin supports diverse aquatic life and is an important ecological corridor in northern France. The advanced treatment helps minimize nutrient loading and protects downstream water quality in the Seine estuary and the English Channel.

The plant discharges into the local water system that flows into the Eure River, a major tributary of the Seine. The Seine basin is ecologically significant, supporting diverse fish species and serving as a migratory route for eels and salmon. Advanced treatment at Senonches reduces nitrogen and phosphorus loads, helping to prevent eutrophication in the Seine estuary and the English Channel.