BAZAS Wastewater Treatment Plant, Bazas, Nouvelle-Aquitaine, France

The BAZAS wastewater treatment plant is located in Bazas, a commune in the Gironde department of Nouvelle-Aquitaine, southwestern France. The facility serves a population of approximately 10,258, classifying it as a medium agglomeration under EU regulations. The plant is situated inland, more than 50 km from the coast, and its treated effluent is discharged into local watercourses that ultimately flow toward the Atlantic Ocean. As a French wastewater treatment facility serving a population between 2,000 and 10,000, the plant is required to meet secondary treatment standards under the EU Urban Waste Water Treatment Directive (91/271/EEC). This directive ensures that organic matter and suspended solids are effectively removed before discharge. Regulatory compliance is expected for facilities of this scale. The treated wastewater from BAZAS is discharged into the local watershed, which drains into the Garonne River via smaller tributaries. The Garonne flows through the Bordeaux region and into the Gironde estuary, eventually reaching the Bay of Biscay. This downstream environment supports diverse aquatic life and is important for regional biodiversity, including migratory fish species such as salmon and eels.

The BAZAS plant discharges into the local watershed that feeds the Garonne River, a major watercourse in southwestern France. The Garonne flows through the Bordeaux wine region and into the Gironde estuary, a large tidal estuary that empties into the Bay of Biscay (Atlantic Ocean). This estuarine environment is ecologically sensitive, supporting diverse fish populations and serving as a critical migratory corridor for species such as Atlantic salmon and European eel. The plant's treatment performance directly affects water quality in these downstream habitats.