Preignac Wastewater Treatment Plant - Nouvelle-Aquitaine, France

The Preignac wastewater treatment plant is located in the commune of Preignac, within the Gironde department of Nouvelle-Aquitaine, southwestern France. The facility serves a population of approximately 1,500 residents and is situated in a rural setting near the Garonne River valley. The plant employs advanced treatment processes, which go beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a design capacity of 2,500 m³/day and an average daily discharge of 267 m³, the plant operates well below its capacity, indicating room for future growth or seasonal variations. Treated effluent is discharged into local watercourses that ultimately drain into the Garonne River, a major river in southwestern France that flows into the Gironde estuary and the Atlantic Ocean. The plant plays a key role in protecting the region's water quality and supporting the ecological health of the Garonne watershed.

The plant discharges into the Garonne River basin, which flows through the wine-growing region of Bordeaux before reaching the Gironde estuary and the Bay of Biscay. The Garonne supports diverse aquatic life, including migratory fish species such as Atlantic salmon and European eel. The advanced treatment helps reduce nutrient loads and protect downstream ecosystems from eutrophication.