LE PLESSIS BRION Wastewater Treatment Plant, Clairoix, Hauts-de-France

LE PLESSIS BRION is a wastewater treatment plant located in Clairoix, within the Oise department of Hauts-de-France, France. The plant serves a population of 2,420 and has a designed capacity of 3,000 m³/day, with an average discharge volume of 431.72 m³/day. The plant provides secondary treatment, which is the standard level required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Secondary treatment typically involves biological processes to remove organic matter and suspended solids, ensuring compliance with European effluent standards. The treated wastewater is discharged into the local water environment, likely the Oise River, which flows into the Seine and eventually the English Channel. The plant plays a key role in protecting the Oise River and downstream ecosystems from pollution, supporting water quality for aquatic life and human use.

The plant discharges into the Oise River, a major tributary of the Seine River, which flows through the Paris Basin and into the English Channel. The Oise River supports diverse aquatic life and is an important water resource for the region. The plant's secondary treatment helps reduce nutrient and organic loads, mitigating eutrophication risks in the downstream Seine estuary and coastal waters.