PLESCOP Le Moustoir Wastewater Treatment Plant, Plescop, Brittany

PLESCOP Le Moustoir is an advanced wastewater treatment plant located in Plescop, a commune in the Morbihan department of Brittany, France. The plant serves a population of approximately 4,957 residents and is situated near the coastal zone of southern Brittany. As part of France's wastewater infrastructure, it plays a key role in protecting local water quality. The plant employs advanced treatment processes, which go beyond secondary treatment to remove nutrients and other pollutants. With a designed capacity of 6,000 m³/day and an average discharge volume of 884.32 m³/day, the facility operates well within its capacity. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), plants serving agglomerations between 2,000 and 10,000 population equivalent require secondary treatment, but this plant's advanced level exceeds that standard, reflecting the sensitivity of the receiving environment. The treated effluent is discharged into local watercourses that drain into the Gulf of Morbihan, a semi-enclosed marine inlet connected to the Atlantic Ocean. The Gulf of Morbihan is an ecologically significant area supporting diverse marine life and migratory birds. By providing advanced treatment, the plant helps minimize nutrient loading and protects the coastal ecosystem.

The plant discharges into the Gulf of Morbihan, a coastal inlet in southern Brittany that connects to the Atlantic Ocean. This area is ecologically sensitive, supporting seagrass beds, shellfish beds, and important bird populations. Advanced treatment reduces nitrogen and phosphorus loads, helping to prevent eutrophication in the gulf's confined waters. The watershed includes agricultural land and small rivers that flow into the gulf, making nutrient management critical for maintaining water quality.