OSORNO Wastewater Treatment Plant, Osorno la Mayor, Castilla y León, Spain

OSORNO is a wastewater treatment plant located in Osorno la Mayor, in the province of Palencia, Castilla y León, Spain. The facility serves a population of approximately 4,125 residents, operating as a municipal treatment works for this inland community. The plant provides secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The designed capacity of 4,125 cubic meters per day matches the population served, indicating a facility sized to handle the community's wastewater load. The daily discharge volume of 684.93 cubic meters suggests the plant operates well within its capacity. The treated effluent is discharged into the local watershed, which ultimately drains into the Duero River basin. The Duero River flows westward through Spain and into Portugal, reaching the Atlantic Ocean near Porto. The plant's operations help protect the water quality of the Duero basin, which supports agriculture, ecosystems, and downstream communities.

The plant discharges into the Duero River basin, one of the largest watersheds in the Iberian Peninsula. The Duero River flows through Castilla y León into Portugal, supporting irrigated agriculture and diverse aquatic habitats. Downstream, the river forms the border between Spain and Portugal before reaching the Atlantic Ocean. The plant's secondary treatment helps reduce organic pollution and nutrient loads, protecting the ecological health of the river and its estuary.