LONGARES Wastewater Treatment Plant, Longares, Aragón, Spain

LONGARES is a municipal wastewater treatment plant located in Longares, within the Campo de Cariñena region of Zaragoza, Aragón, Spain. The plant serves a population of approximately 5,199 people, classifying it as a small to medium agglomeration under Spanish and EU regulations. The plant provides secondary treatment, which is the minimum standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for freshwater discharges from agglomerations of this size. The designed capacity of 4,000 m³/day indicates the plant is sized to handle peak flows, while the average discharge volume of 942.30 m³/day suggests current flows are well within capacity. The treated effluent is discharged into local watercourses that ultimately drain into the Ebro River basin, one of Spain's major river systems. The Ebro River flows into the Mediterranean Sea via the Ebro Delta, a region of high ecological importance. The plant's secondary treatment helps protect downstream water quality and supports the ecological health of the Ebro watershed.

The plant discharges into local streams that are part of the Ebro River basin. The Ebro River flows eastward through Aragón and Catalonia before forming the Ebro Delta, a large wetland area that supports diverse aquatic life and serves as an important migratory corridor for birds. Secondary treatment reduces organic pollutants and suspended solids, helping to maintain water quality in the river system and protect the downstream delta ecosystem.