AURILLAC SOULEYRIE Wastewater Treatment Plant, Arpajon-sur-Cère, France

AURILLAC SOULEYRIE is a wastewater treatment plant located in Arpajon-sur-Cère, near Aurillac, in the Cantal department of Auvergne-Rhône-Alpes, France. The plant serves a population of approximately 61,152 people, placing it in the medium agglomeration category under EU classification. Under the EU Urban Waste Water Treatment Directive 91/271/EEC, plants serving agglomerations of this size are required to provide secondary treatment as a minimum. In sensitive areas, more stringent treatment may be mandated. It operates within France's national regulatory framework, which implements the directive. The plant discharges treated wastewater into the local watershed, which ultimately drains into the Cère River and then the Dordogne River system. This river network supports diverse aquatic life and is important for regional water quality. The plant's location inland, over 50 km from the coast, reduces direct marine impact but requires careful management to protect freshwater ecosystems.

The plant's treated effluent enters the Cère River, a tributary of the Dordogne River, which flows into the Garonne estuary and eventually the Atlantic Ocean. The Dordogne basin is ecologically significant, supporting species such as Atlantic salmon and European otter. The plant's discharge must comply with French water quality standards to protect this sensitive river system.