ARROYO DE LA ENCOMIENDA Wastewater Treatment Plant, Arroyo de la Encomienda, Spain

The ARROYO DE LA ENCOMIENDA wastewater treatment plant is located in the municipality of Arroyo de la Encomienda, within the province of Valladolid in the autonomous community of Castilla y León, Spain. The plant serves a population of approximately 9,000 people, placing it in the small-to-medium agglomeration category under Spanish and EU regulations. As a Spanish facility, the plant operates under the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires secondary treatment for agglomerations of this size. The directive also mandates more stringent treatment if the receiving waters are designated as sensitive areas. The regulatory framework ensures compliance with national and European standards. The treated effluent from the plant is discharged into local water bodies that ultimately drain into the Duero River basin, one of the major river systems in the Iberian Peninsula. The Duero River flows westward through Spain and Portugal, emptying into the Atlantic Ocean near Porto. The plant plays a key role in protecting the water quality of this important basin, supporting aquatic ecosystems and downstream water uses.

The plant discharges into the Duero River basin, which drains a large area of northern Spain and Portugal before reaching the Atlantic Ocean. The Duero River supports diverse aquatic life and is an important resource for agriculture and drinking water. The plant's operations help maintain water quality in this ecologically sensitive basin, reducing nutrient loads and protecting downstream habitats.