LA MONGIE Wastewater Treatment Plant - Bagnères-de-Bigorre, Occitanie, France

LA MONGIE is a wastewater treatment plant located in the mountain village of La Mongie, part of the commune of Bagnères-de-Bigorre in the Hautes-Pyrénées department of Occitanie, France. The plant serves a population of 5,200, primarily supporting the seasonal tourism of the ski resort. It is situated in the Pyrenees mountain range, at an altitude of approximately 1,800 meters. The plant employs advanced treatment processes, which go beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a designed capacity of 9,500 m³/day and a current discharge volume of 927.67 m³/day, the plant has significant reserve capacity to handle peak tourist loads. The advanced treatment likely includes nutrient removal to protect sensitive mountain streams. The treated effluent is discharged into the local watershed, which feeds into the Adour River system. The Adour flows northward through the Pyrenees foothills and eventually reaches the Bay of Biscay near Bayonne. The plant's advanced treatment helps protect the fragile alpine aquatic ecosystems and downstream water quality in the Adour basin.

The plant discharges into the mountain streams of the Pyrenees, which are part of the Adour River basin. The Adour flows through the Hautes-Pyrénées and Landes regions before emptying into the Bay of Biscay. These alpine streams support sensitive aquatic life, including brown trout and Pyrenean desman, and are important for downstream water quality in the Adour estuary.