BAILLEUL SUR THERAIN Wastewater Treatment Plant, Bailleul-sur-Thérain, Hauts-de-France

BAILLEUL SUR THERAIN is a wastewater treatment plant located in Bailleul-sur-Thérain, within the Oise department of Hauts-de-France, France. The plant serves a population of approximately 3,604 people, classifying it as a small agglomeration under French and EU regulations. The plant operates with advanced treatment, which goes 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, and it currently discharges 642.95 m³/day of treated wastewater. The treated effluent is discharged into the local watershed, which ultimately drains into the Thérain River, a tributary of the Oise River. The Oise flows into the Seine River, which reaches the English Channel. The plant plays a key role in protecting the water quality of these rivers and the downstream marine environment.

The plant discharges into the Thérain River, a tributary of the Oise River, which flows into the Seine River and eventually the English Channel. The watershed supports diverse aquatic life and is important for regional water quality. Advanced treatment helps reduce nutrient loads, protecting downstream ecosystems from eutrophication.