NAJAC Wastewater Treatment Plant, Najac, Occitanie, France

The NAJAC wastewater treatment plant is located in the commune of Najac, within the Aveyron department of Occitanie, southern France. This facility serves a population of approximately 1,509 residents, reflecting its role in managing domestic wastewater for a small rural community. The plant is situated inland, away from coastal areas, and operates under the regulatory framework of the European Union's Urban Waste Water Treatment Directive (91/271/EEC). The plant employs advanced treatment processes, which go beyond the secondary treatment standard typically required for agglomerations of this size under the EU directive. Advanced treatment often includes nutrient removal (nitrogen and phosphorus) to protect sensitive receiving waters. The designed capacity of 2,500 m³/day indicates that the plant has headroom for future growth or seasonal variations, with a current discharge volume of 269.20 m³/day. The treated effluent is discharged into a local watercourse that ultimately drains into the Aveyron River, a tributary of the Tarn River, which flows into the Garonne River and eventually reaches the Atlantic Ocean via the Gironde estuary. The plant's advanced treatment helps protect the ecological health of these downstream waters, supporting aquatic life and water quality in the region.

The plant discharges into a local stream that feeds into the Aveyron River, part of the Garonne basin. The Aveyron River supports diverse aquatic ecosystems and is used for recreation and agriculture. Advanced treatment at this plant reduces nutrient loads, helping to prevent eutrophication in downstream water bodies, including the Garonne estuary and the Atlantic Ocean.