SAINT MELOIR 1 Wastewater Treatment Plant, Saint-Méloir-des-Ondes, Brittany

SAINT MELOIR 1 is a municipal wastewater treatment plant located in Saint-Méloir-des-Ondes, a commune in the Ille-et-Vilaine department of Brittany, northwestern France. The plant serves a population of approximately 2,650 residents, placing it in the small agglomeration category under the EU Urban Waste Water Treatment Directive (UWWTD). The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU UWWTD for agglomerations of this size. With a design capacity of 3,000 cubic meters per day and a current discharge volume of 472.76 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. As a coastal plant (within 10 km of the coast), it likely adheres to stricter discharge standards to protect marine environments. The treated effluent is discharged into the local watershed, which ultimately drains into the English Channel via the Rance estuary or nearby coastal waters. This area supports diverse marine life and is part of the broader Brittany coastal ecosystem, known for its rich biodiversity and important fisheries. The plant's advanced treatment helps minimize nutrient loading and protect downstream water quality.

The plant discharges into the coastal watershed of the English Channel near Saint-Malo. The receiving waters are part of the Rance estuary and the Baie du Mont-Saint-Michel, a ecologically significant area supporting migratory birds, fish, and marine habitats. Advanced treatment reduces nutrient and pollutant loads, protecting the sensitive coastal environment from eutrophication and preserving water quality for tourism and fisheries.