REMOLINOS Wastewater Treatment Plant, Alcalá de Ebro, Aragón, Spain

REMOLINOS is a wastewater treatment plant located in Alcalá de Ebro, within the Ribera Alta del Ebro region of Zaragoza, Aragón, Spain. The plant serves a population of approximately 4,445 people, classifying it as a small agglomeration under Spanish and EU regulations. The plant provides secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for inland freshwater discharges from agglomerations of this size. With a designed capacity of 4,958 m³/day and an average discharge volume of 805.64 m³/day, the plant operates well below its capacity, indicating room for future growth or seasonal variations. Treated effluent from REMOLINOS is discharged into the Ebro River basin, which flows through northeastern Spain and ultimately reaches the Mediterranean Sea via the Ebro Delta. The Ebro River is a vital ecological corridor, supporting diverse aquatic life and irrigating extensive agricultural lands. The plant's secondary treatment helps protect water quality in this important river system.

The plant discharges into the Ebro River basin, which drains into the Mediterranean Sea through the Ebro Delta. The Ebro River supports a rich ecosystem, including fish species such as the European eel and various waterfowl. Secondary treatment reduces organic pollutants and suspended solids, helping to maintain the ecological health of the river and downstream coastal waters.