MONTIGNY SUR AIN Wastewater Treatment Plant, Hauteroche, France

MONTIGNY SUR AIN is an advanced wastewater treatment plant located in Hauteroche, in the Jura department of Bourgogne-Franche-Comté, France. The plant serves a population of 4,100 and has a designed capacity of 7,000 m³/day, with a current discharge volume of 731.43 m³/day. As an advanced treatment facility, it goes beyond secondary treatment to remove nutrients and other pollutants, meeting stringent French and EU standards. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), plants serving agglomerations between 2,000 and 10,000 population equivalent are required to provide secondary treatment, but France often mandates advanced treatment in sensitive areas like the Jura region. The treated effluent is discharged into the Ain River basin, which flows into the Rhône River and eventually the Mediterranean Sea. The plant plays a key role in protecting the region's karstic groundwater and surface waters, which support diverse aquatic life and are important for local agriculture and tourism.

The plant discharges into the Ain River watershed, a tributary of the Rhône River. The Rhône flows into the Mediterranean Sea, making this plant part of a large transboundary basin. The Jura region features karstic geology, where groundwater and surface water are closely connected, so advanced treatment is critical to prevent nutrient pollution and protect sensitive aquatic ecosystems downstream.