PERSAN Wastewater Treatment Plant, Persan, Val-d'Oise, France

The PERSAN wastewater treatment plant is located in Persan, a commune in the Val-d'Oise department of northern France, within the Île-de-France region. The facility serves a population of approximately 34,583, classifying it as a medium-sized agglomeration under EU regulations. Its address on Chemin de Halage places it near the Oise River, a key waterway in the region. As a French plant serving over 10,000 people, PERSAN is subject to the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary biological treatment as a minimum. For agglomerations between 10,000 and 150,000 population equivalent, the directive also mandates more stringent treatment if the receiving waters are designated as sensitive areas. The regulatory framework ensures compliance with European standards. The treated effluent from PERSAN is discharged into the Oise River, a major tributary of the Seine. The Oise flows through the Paris Basin and eventually joins the Seine near Conflans-Sainte-Honorine, contributing to the Seine's journey to the English Channel. This watershed supports diverse aquatic life and is an important ecological corridor in northern France. The plant plays a crucial role in protecting the Oise River from nutrient pollution and organic loads, helping maintain water quality for downstream communities and ecosystems.

PERSAN discharges into the Oise River, which flows into the Seine River and ultimately reaches the English Channel. The Oise basin supports diverse aquatic habitats and is an important migratory corridor for fish species. The plant's treatment helps reduce nutrient and organic pollution, protecting downstream water quality in the Seine estuary and coastal zone.