Negrepelisse filtres Wastewater Treatment Plant, Nègrepelisse, Occitanie

Negrepelisse filtres is a municipal wastewater treatment plant located in Nègrepelisse, a commune in the Tarn-et-Garonne department of Occitanie, southern France. The plant serves a population of approximately 3,200 residents and is designed to handle up to 4,000 cubic meters of wastewater per day, with an average daily discharge of 570.87 cubic meters. The plant provides secondary treatment, which is the standard biological treatment stage required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Secondary treatment typically involves biological oxidation and sedimentation to remove organic matter and suspended solids, ensuring compliance with EU effluent quality standards before discharge. The treated effluent is discharged into the local watershed, which ultimately drains into the Tarn River, a major tributary of the Garonne River. The Garonne flows into the Gironde estuary and then the Atlantic Ocean. The plant plays a key role in protecting the water quality of the Tarn River and downstream ecosystems, supporting aquatic life and recreational uses.

The plant discharges into the Tarn River basin, which flows through the Occitanie region and joins the Garonne River near Moissac. The Garonne then forms the Gironde estuary, a large and ecologically important coastal ecosystem that supports diverse fish and bird species. The Tarn River itself is a dynamic watercourse with seasonal flow variations, and the plant's secondary treatment helps reduce nutrient and organic pollution, mitigating eutrophication risks in downstream waters.