CHATELAUDREN Wastewater Treatment Plant, Châtelaudren-Plouagat, Bretagne

The CHATELAUDREN wastewater treatment plant is located in Kerlee les Fontaines, Plouagat, within the commune of Châtelaudren-Plouagat in the Côtes-d'Armor department of Bretagne, France. It serves a population equivalent of 9,990, classifying it as a medium-sized agglomeration under French regulations. As a plant in France, it operates under the national transposition of the EU Urban Waste Water Treatment Directive (91/271/EEC). For agglomerations of this scale (between 2,000 and 10,000 population equivalent), the directive requires secondary treatment as a minimum, with more stringent treatment in sensitive areas. The treated effluent is discharged into the local watershed, which ultimately drains into the English Channel via the Trieux River and its estuary. This coastal region supports diverse aquatic life and is important for migratory fish species. The plant's location in inland Bretagne, over 50 km from the coast, reduces direct marine impact.

The plant discharges into the Trieux River basin, which flows northward through Côtes-d'Armor into the English Channel near Lézardrieux. The Trieux estuary is a dynamic coastal environment supporting diverse aquatic life, including migratory fish such as salmon and sea trout. The watershed is predominantly agricultural, with some urban influence from Guingamp, and the plant's treatment performance is critical to maintaining water quality in this sensitive coastal ecosystem.