Saâcy-sur-Marne Wastewater Treatment Plant | Advanced Treatment, Marne River Discharge

The Saâcy-sur-Marne wastewater treatment plant is located in the commune of Saâcy-sur-Marne, within the Seine-et-Marne department of the Île-de-France region. It serves a population of approximately 3,628 residents, classifying it as a small agglomeration under French and EU regulations. The plant is situated near the Marne River, a major tributary of the Seine. The facility employs advanced treatment processes, which go beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) to protect sensitive water bodies. The plant has a designed capacity of 6,500 cubic meters per day, with a current discharge volume of 647.23 cubic meters per day, indicating ample reserve capacity. The treated effluent is discharged into the Marne River, which flows westward to join the Seine near Paris. The Seine then continues to the English Channel via the Seine estuary. The plant's advanced treatment helps protect the Marne and Seine ecosystems, supporting aquatic life and water quality for downstream communities, including the Paris metropolitan area.

The plant discharges into the Marne River, a major tributary of the Seine River. The Seine flows through Paris and eventually reaches the English Channel via the Seine estuary. The Marne and Seine watersheds support diverse aquatic ecosystems and are important for recreation, drinking water supply, and biodiversity. Advanced treatment at this plant reduces nutrient loads, helping to prevent eutrophication in downstream waters, including the sensitive Seine estuary.