SAINT YZAN DE SOUDIAC Wastewater Treatment Plant, Saint-Yzan-de-Soudiac, Nouvelle-Aquitaine

SAINT YZAN DE SOUDIAC is a municipal wastewater treatment plant located in Saint-Yzan-de-Soudiac, a commune in the Gironde department of Nouvelle-Aquitaine, southwestern France. The plant serves a population of approximately 2,765 residents and is situated inland, more than 10 km from the Atlantic coast. The plant provides secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Its designed capacity is 2,800 m³/day, and it currently discharges an average of 493.27 m³/day of treated wastewater. The facility is part of France's national wastewater infrastructure, regulated by the French Ministry of Ecology and local water agencies. The treated effluent is discharged into a local watercourse that ultimately drains into the Garonne River and then the Gironde estuary, a major tidal estuary on the Atlantic coast. This estuary supports diverse aquatic life and is an important migratory corridor for fish species such as salmon and eels. The plant's secondary treatment helps protect the downstream ecosystem from organic pollution.

The plant discharges into a tributary of the Garonne River, which flows into the Gironde estuary, the largest estuary in western Europe. The estuary is ecologically sensitive, supporting diverse aquatic life and serving as a critical migratory corridor for fish. Secondary treatment reduces organic load and suspended solids, helping to maintain water quality in this dynamic tidal environment.