GUARDO Wastewater Treatment Plant, Guardo, Castilla y León, Spain

The GUARDO wastewater treatment plant is located in the town of Guardo, within the province of Palencia in the autonomous community of Castilla y León, Spain. The facility serves a population equivalent of 15,850, classifying it as a medium-sized agglomeration under European Union regulations. As a plant in Spain, GUARDO is subject to the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for discharges from agglomerations with a population equivalent between 2,000 and 15,000, and more stringent treatment for larger agglomerations in sensitive areas. The plant's treatment process and capacity are designed to meet these regulatory standards, ensuring compliance with national and European water quality objectives. The treated effluent from the GUARDO plant is discharged into the local watershed, which ultimately drains into the Carrión River, a tributary of the Pisuerga River, and then into the Duero River basin. The Duero River flows westward through Spain and into Portugal, emptying into the Atlantic Ocean near Porto. The plant plays a key role in protecting the water quality of the Carrión River and the downstream Duero basin, supporting aquatic life and downstream water uses.

The GUARDO plant discharges into the Carrión River, which flows into the Pisuerga River, a major tributary of the Duero River. The Duero basin is one of the largest in the Iberian Peninsula, supporting diverse aquatic ecosystems and providing water for agriculture and human consumption. The plant's treatment helps maintain the ecological health of the Carrión River and contributes to the overall water quality of the Duero basin, which eventually reaches the Atlantic Ocean.