BILLOM Bourg Wastewater Treatment Plant, Espirat, Auvergne-Rhône-Alpes

BILLOM Bourg is a wastewater treatment plant located near Espirat in the Auvergne-Rhône-Alpes region of France. The facility serves a population of approximately 6,786 people, classifying it as a small to medium agglomeration under EU classification. Its location in the Puy-de-Dôme department places it within a region known for its volcanic landscapes and agricultural activity. As a French plant serving fewer than 10,000 people, BILLOM Bourg is subject to the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires appropriate treatment based on the sensitivity of the receiving environment. For agglomerations of this size, secondary treatment is typically mandated unless the discharge is into a less sensitive area. The regulatory framework ensures compliance with national standards set by the French Ministry of Ecology. The treated effluent from BILLOM Bourg is discharged into a local watercourse that eventually drains into the Loire River basin, one of France's major river systems. The Loire flows westward to the Atlantic Ocean, supporting diverse aquatic ecosystems and agricultural water use. The plant plays a role in protecting local water quality in the Allier River tributaries, which are important for regional biodiversity and recreational activities.

The plant discharges into a tributary of the Allier River, which flows into the Loire River, the longest river in France. The Loire basin supports a variety of aquatic habitats and is known for its migratory fish species such as Atlantic salmon and European eel. The region's volcanic soils and agricultural land use mean that nutrient management is important to prevent eutrophication in downstream waters. The plant's treatment helps maintain water quality in this ecologically sensitive river system.