IBOS nouvelle Step Wastewater Treatment Plant, Ibos, Occitanie

IBOS nouvelle Step is a municipal wastewater treatment plant located in Ibos, a commune in the Hautes-Pyrénées department of Occitanie, southern France. The plant serves a population of approximately 4,300 residents and operates under the regulatory framework of the European Union's Urban Waste Water Treatment Directive (91/271/EEC), which France transposes into national law. As a secondary treatment facility, it provides biological treatment to reduce organic matter and suspended solids before discharge. The plant's designed capacity is 2,400 m³/day, and it currently treats an average daily flow of 767.11 m³/day, indicating operational headroom. For agglomerations of this size (4,300 PE), the EU directive requires secondary treatment as a minimum standard. The plant's performance is monitored by French water agencies (Agences de l'Eau) under the national water law (Loi sur l'Eau), ensuring compliance with discharge standards. The treated effluent is discharged into a local watercourse that eventually flows into the Adour River basin. The Adour River drains into the Bay of Biscay (Atlantic Ocean) near Bayonne. The plant plays a key role in protecting the local aquatic environment by reducing nutrient and organic pollution loads, supporting the ecological health of the downstream river system and the coastal waters of the Atlantic.

The plant discharges into a tributary of the Adour River, which flows through the Pyrénées-Atlantiques region before reaching the Bay of Biscay. The Adour basin supports diverse aquatic life, including migratory fish species such as salmon and eel. Downstream, the estuary and coastal waters are ecologically sensitive areas that benefit from reduced nutrient inputs from upstream treatment plants like IBOS nouvelle Step.