SARINENA Wastewater Treatment Plant, Sariñena, Aragón, Spain

SARINENA is a municipal wastewater treatment plant located in Sariñena, within the Los Monegros region of Huesca, Aragón, Spain. The plant serves a population of approximately 4,154 residents, classifying it as a small agglomeration under Spanish and EU regulations. Its designed capacity is 9,167 m³/day, with a current discharge volume of 752.90 m³/day, indicating operational headroom. The plant provides secondary treatment, which is the minimum required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for inland freshwater discharges from agglomerations of this size. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids, ensuring compliance with EU effluent standards before discharge. The treated effluent is discharged into local watercourses within the Ebro River basin, which ultimately flows into the Mediterranean Sea. The plant plays a key role in protecting the region's water quality, particularly in the semi-arid Los Monegros area where water resources are scarce and ecologically sensitive.

The plant discharges into the Ebro River basin, which drains into the Mediterranean Sea via the Ebro Delta, a region of high ecological importance. The receiving waters support diverse aquatic life and are part of a semi-arid landscape where water quality is critical for both human use and natural habitats. The plant's secondary treatment helps reduce nutrient and organic pollution, mitigating eutrophication risks in downstream water bodies.