ELCIEGO Wastewater Treatment Plant, Elciego, Basque Country, Spain

ELCIEGO is a wastewater treatment plant located in Elciego, a town in the Basque Country (Euskadi), Spain. The facility serves a population of around 9,750, classifying it as a small to medium agglomeration under European Union regulations. The plant is situated inland, away from the coast, and discharges into local watercourses that eventually drain into the Ebro River basin. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), treatment plants serving agglomerations of this size are required to provide secondary treatment as a minimum. The directive also mandates more stringent treatment if the receiving waters are designated as sensitive areas. The plant's operational details, including specific treatment processes and capacity, are managed by the local water authority to ensure compliance with Spanish and EU environmental standards. The treated effluent from the plant flows into the Ebro River system, which is one of the most important rivers in Spain, supporting diverse aquatic life and agricultural activities in the region. The Ebro River ultimately discharges into the Mediterranean Sea via the Ebro Delta, a ecologically significant area known for its wetlands and bird populations. The plant plays a key role in protecting downstream water quality and the ecological health of the Ebro basin.

The plant discharges into the Ebro River basin, which flows through northeastern Spain and empties into the Mediterranean Sea via the Ebro Delta. The delta is a critical habitat for migratory birds and supports extensive rice farming. The plant's treatment helps reduce nutrient loading and protect the delta's sensitive ecosystems from eutrophication.