PARIS Marne Aval Wastewater Treatment Plant, Saint-Maur-des-Fossés, France

PARIS Marne Aval is a major wastewater treatment facility located in Saint-Maur-des-Fossés, a suburb east of Paris in the Île-de-France region. Serving a population of approximately 370,000, it is classified as a large agglomeration under EU regulations, requiring advanced treatment to protect sensitive receiving waters. As a plant of this scale in France, it is subject to the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates secondary treatment as a minimum and tertiary treatment in sensitive areas. The plant's treatment processes are designed to meet these rigorous standards, ensuring high-quality effluent before discharge into the local water system. The treated wastewater from PARIS Marne Aval is discharged into the Marne River, a major tributary of the Seine. The Seine basin supports diverse aquatic life and is a critical water resource for the Paris metropolitan area. Downstream, the Seine flows into the English Channel, making the plant's performance important for both local and coastal water quality.

The plant discharges into the Marne River, which flows into the Seine River and ultimately reaches the English Channel. The Seine basin is ecologically significant, supporting fish populations such as pike and perch, and providing habitat for migratory birds. The plant's advanced treatment helps reduce nutrient loads that could otherwise contribute to eutrophication in downstream coastal waters.