BREIL Wastewater Treatment Plant, Châtillon, Valle d'Aosta, Italy

BREIL is a wastewater treatment plant located in Châtillon, in the Valle d'Aosta region of northwestern Italy. The facility serves a population of approximately 1,200 residents, making it a small-scale municipal treatment plant in the Alpine valley. The plant provides secondary treatment, which is the standard biological treatment stage required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations with a population equivalent between 2,000 and 10,000. Secondary treatment typically involves biological oxidation and settling to reduce organic matter and suspended solids. The treated wastewater is discharged into the local watershed, which ultimately drains into the Dora Baltea River, a tributary of the Po River. The Po River flows eastward across northern Italy into the Adriatic Sea. The plant's location in a mountainous region means the receiving waters are likely sensitive to nutrient loading, supporting aquatic life in the Alpine ecosystem.

The plant discharges into the Dora Baltea River, which flows through the Aosta Valley and joins the Po River near Turin. The Po River is Italy's longest river and drains into the Adriatic Sea, supporting diverse aquatic habitats and important agricultural regions. The Alpine watershed is ecologically sensitive, with cold-water fish species and riparian ecosystems that benefit from well-treated effluent.