ST ASTIER Wastewater Treatment Plant, Saint-Astier, Nouvelle-Aquitaine

ST ASTIER is a wastewater treatment plant located in Saint-Astier, in the Dordogne department of Nouvelle-Aquitaine, France. The facility serves a population of approximately 6,790 residents, classifying it as a small agglomeration under EU regulations. As a French plant, it operates under the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires appropriate treatment for discharges into freshwater and estuarine areas. For agglomerations of this size, secondary treatment is typically mandated unless the receiving water is designated as a sensitive area, which may require more advanced treatment. The plant's treated effluent is discharged into the local watershed, which ultimately drains into the Isle River, a tributary of the Dordogne River. The Dordogne River flows into the Gironde estuary and then the Atlantic Ocean. The facility plays a key role in protecting the water quality of the Isle River and downstream ecosystems.

The plant discharges into the Isle River, which flows into the Dordogne River, a major watercourse in southwestern France. The Dordogne River is part of the Gironde estuary system, one of the largest estuaries in Europe, supporting diverse aquatic life including migratory fish species such as salmon and eels. The watershed is ecologically sensitive due to its biodiversity and the presence of important habitats for birds and aquatic fauna.