BONNELLES Wastewater Treatment Plant, Bonnelles, Île-de-France

The BONNELLES wastewater treatment plant is located in the commune of Bonnelles, within the Yvelines department of the Île-de-France region, France. The facility serves a population of approximately 3,500 residents and is situated in a rural setting near the Rambouillet forest. As a municipal plant, it plays a key role in managing local wastewater for this small agglomeration. The plant operates with advanced treatment, which goes beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The designed capacity of 3,500 m³/day matches the population served, indicating adequate infrastructure. The plant's discharge volume is reported at 624.39 m³/day, suggesting a utilization rate well below capacity. The treated effluent is discharged into local watercourses that eventually drain into the Seine River basin. The Seine flows through Paris and into the English Channel, making the plant's advanced treatment important for protecting downstream water quality. The surrounding area includes sensitive natural habitats such as the Rambouillet forest, which supports diverse wildlife.

The plant discharges into small streams that feed the Orge River, a tributary of the Seine. The Seine River flows through the Paris metropolitan area and ultimately reaches the English Channel. The advanced treatment helps protect the Seine basin from nutrient pollution, which can cause eutrophication in coastal waters. The nearby Rambouillet forest and its wetlands are ecologically sensitive areas that benefit from reduced pollutant loads.