LA SECA Wastewater Treatment Plant, La Seca, Castilla y León, Spain

LA SECA is a wastewater treatment plant located in La Seca, a municipality in the province of Valladolid, within the autonomous community of Castilla y León, Spain. The plant serves a population of approximately 3,000 people and operates with 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 plant has a designed capacity of 3,000 cubic meters per day and currently discharges 256.03 cubic meters of treated effluent daily. As a secondary treatment facility, LA SECA removes organic matter and suspended solids through biological processes, meeting the EU directive's requirements for inland discharges. The plant's capacity utilization is low relative to its design, indicating it serves a small, stable community. The regulatory framework in Spain, transposing the EU directive, mandates that agglomerations with a population equivalent (PE) between 2,000 and 10,000 must have collection systems and appropriate treatment, which LA SECA fulfills. The treated effluent from LA SECA is discharged into a local watercourse that eventually drains 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 at Porto. The plant's operations help protect the local aquatic ecosystem and downstream water quality in the Duero basin, supporting biodiversity and agricultural uses.

LA SECA discharges treated wastewater into a local tributary within the Duero River basin. The Duero River is the third-longest river in the Iberian Peninsula, flowing through Spain and Portugal to the Atlantic Ocean. The basin supports diverse aquatic life and is important for irrigation and drinking water supply. The plant's secondary treatment reduces organic pollution and protects the ecological health of the receiving water body and downstream environments.