UZEIN Wastewater Treatment Plant, Caubios-Loos, Nouvelle-Aquitaine

The UZEIN wastewater treatment plant is located in Caubios-Loos, a commune in the Pyrénées-Atlantiques department of Nouvelle-Aquitaine, southwestern France. It serves a population of about 15,213, classifying it as a medium-sized agglomeration under French and EU regulations. The plant is situated near the city of Pau and operates within the region's municipal wastewater infrastructure. As a facility serving a population equivalent between 10,000 and 100,000, UZEIN is subject to the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment as a minimum standard. French national regulations transpose this directive, and the plant is expected to comply with discharge standards set by the local water agency (Agence de l'Eau Adour-Garonne). The treatment process likely includes biological treatment to reduce organic matter and nutrients before discharge. The treated effluent from UZEIN is discharged into the local watershed, which ultimately drains into the Adour River basin. The Adour River flows through the Basque Country and into the Bay of Biscay (Atlantic Ocean). The plant plays a key role in protecting the region's water quality, supporting aquatic ecosystems in the Adour and its tributaries, and contributing to the ecological health of the coastal marine environment.

The UZEIN plant discharges into the Adour River basin, which flows through southwestern France and empties into the Bay of Biscay. This watershed supports diverse freshwater and estuarine habitats, including migratory fish species such as salmon and eel. The plant's treatment performance is critical to maintaining water quality in the Adour and its tributaries, which are ecologically sensitive and support local agriculture and tourism.