Pierrefonds Wastewater Treatment Plant, Hauts-de-France, France

The Pierrefonds wastewater treatment plant is located in the commune of Pierrefonds, within the Oise department of Hauts-de-France, France. It serves a population of 1,863, classifying it as a small agglomeration under EU regulations. The plant is situated inland, away from coastal areas, and treats wastewater from the local community. The facility employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Its designed capacity is 4,000 cubic meters per day, with an average discharge volume of 332.36 cubic meters per day, indicating ample capacity for current loads. The plant's advanced treatment ensures high-quality effluent suitable for discharge into sensitive environments. The treated effluent is discharged into local watercourses that eventually flow into the Oise River, a major tributary of the Seine River. The Seine basin is ecologically significant, supporting diverse aquatic life and providing water for agriculture and recreation. The plant's advanced treatment helps protect downstream water quality in this important river system.

The plant discharges into the local watershed, which drains into the Oise River and ultimately the Seine River. The Seine basin is a densely populated and agriculturally intensive region, making nutrient removal critical to prevent eutrophication. The advanced treatment at Pierrefonds helps reduce nitrogen and phosphorus loads, safeguarding aquatic habitats and supporting biodiversity in the river and its estuary.