CEBOLLA Wastewater Treatment Plant, Cebolla, Castilla-La Mancha, Spain

The CEBOLLA wastewater treatment plant is located in Cebolla, a municipality in the province of Toledo, within the autonomous community of Castilla-La Mancha, Spain. The plant serves a population of about 6,924 residents, classifying it as a small to medium agglomeration under Spanish and EU regulations. The plant operates with secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for 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. The treated wastewater is discharged into the local hydrological network, which ultimately drains into the Tagus River basin. The Tagus River is the longest river in the Iberian Peninsula and flows westward into the Atlantic Ocean near Lisbon. The plant's operations contribute to protecting the water quality of the Tagus basin, which supports diverse aquatic life and is used for irrigation and drinking water supply downstream.

The CEBOLLA plant discharges into the Tagus River basin, a major Iberian watershed that flows through central Spain and Portugal before reaching the Atlantic Ocean. The Tagus River supports a variety of fish species and provides water for agriculture and urban use. The plant's secondary treatment helps reduce nutrient and organic pollution, mitigating eutrophication risks in the river and its estuary.