ALCORISA Wastewater Treatment Plant, Alcorisa, Aragón, Spain

ALCORISA is a municipal wastewater treatment plant located in Alcorisa, a town in the Bajo Aragón region of Aragón, Spain. The plant serves a population of approximately 5,460 people and operates under Spain's implementation of the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations of this size. The plant provides secondary treatment, a standard biological process that removes organic matter and suspended solids. With a designed capacity of 5,647 m³/day and an average daily discharge of 989.61 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. The plant's performance is regulated under Spanish national law, which transposes EU directives and sets effluent quality standards. Treated effluent from the plant is discharged into the local hydrological network, which ultimately drains into the Ebro River basin, one of Spain's major river systems. The Ebro River flows into the Mediterranean Sea via the Ebro Delta, an ecologically important area that supports diverse aquatic life and migratory bird populations. The plant plays a key role in protecting downstream water quality in this sensitive region.

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 numerous bird species and supports rich biodiversity. Secondary treatment helps reduce nutrient and organic loads, mitigating eutrophication risks in the river and coastal waters. The plant's location inland, over 50 km from the coast, means its discharge undergoes significant dilution and natural attenuation before reaching the sea.