SAIX SEMALENS Wastewater Treatment Plant, Fréjeville, Occitanie, France

SAIX SEMALENS is a wastewater treatment plant located in Fréjeville, within the Occitanie region of southern France. It serves a population of approximately 2,234 residents, operating as a secondary treatment facility under the regulatory framework of the European Union's Urban Waste Water Treatment Directive (91/271/EEC). The plant has a designed capacity of 4,500 m³/day and currently discharges 398.54 m³/day of treated wastewater. As a secondary treatment plant, it meets the EU standards for biological treatment, which are required for agglomerations of this size. The facility is part of France's national water management system, overseen by local water agencies. The treated effluent is discharged into the local watershed, which ultimately drains into the Tarn River, a tributary of the Garonne River, and then into the Atlantic Ocean via the Gironde estuary. The plant plays a key role in protecting the water quality of the Tarn River and its downstream ecosystems, supporting aquatic life and recreational uses.

The plant discharges into the Tarn River basin, which flows into the Garonne River and eventually the Atlantic Ocean. The Tarn River supports diverse aquatic life and is an important ecological corridor in the Occitanie region. The secondary treatment provided by the plant helps reduce organic pollutants and nutrients, safeguarding water quality for downstream communities and habitats.