CAILLAC 2 Wastewater Treatment Plant, Caillac, Occitanie, France

CAILLAC 2 is an advanced wastewater treatment plant located in Caillac, a commune in the Lot department of Occitanie, southern France. The plant serves a population of approximately 3,320 people, reflecting its role in managing municipal wastewater for a small agglomeration. Its designed capacity of 5,000 m³/day indicates sufficient headroom for current and future demand. The plant provides advanced treatment, which goes beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) to protect sensitive receiving waters. As a French facility, it operates under national regulations transposing the directive, with oversight from the local water agency (Agence de l'Eau). The treated effluent is discharged into the local watershed, which ultimately drains into the Lot River, a tributary of the Garonne River. The Garonne flows into the Gironde estuary and the Atlantic Ocean. The plant's advanced treatment helps safeguard water quality in this ecologically important river system, which supports diverse aquatic life and is used for recreation and agriculture.

The plant discharges into the local watershed, which feeds into the Lot River, a major tributary of the Garonne River. The Garonne flows through southwestern France into the Gironde estuary, a large and ecologically productive estuary that supports migratory fish species such as Atlantic salmon and European eel. The advanced treatment at CAILLAC 2 helps reduce nutrient loads, protecting downstream water quality and aquatic habitats.