FONTENAY LES BRIIS Wastewater Treatment Plant, Courson-Monteloup, France

The FONTENAY LES BRIIS wastewater treatment plant is located in Courson-Monteloup, a commune in the Essonne department of Île-de-France, France. The plant serves a population of approximately 3,779 and has a designed capacity of 5,000 m³/day, with an average discharge volume of 674.17 m³/day. As a secondary treatment facility, the plant meets the requirements of the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates secondary treatment for agglomerations with a population equivalent (PE) between 2,000 and 10,000. The plant's scale places it in the small agglomeration category, and it operates under French national regulations that transpose the directive. The plant discharges treated wastewater into the local watershed, which ultimately drains into the Seine River basin. The Seine flows through Paris and into the English Channel, supporting diverse aquatic life and providing water for agricultural and industrial use downstream. The plant's treatment helps protect the Seine's water quality and the ecological health of the estuary.

The plant discharges into the local watershed within the Seine River basin, which flows through Île-de-France and eventually reaches the English Channel. The Seine supports a variety of fish species and is an important migratory corridor for eels and salmon. The plant's secondary treatment reduces organic pollutants and suspended solids, contributing to the ecological health of the river and its downstream estuary.