QUERO Wastewater Treatment Plant, Quero, Castilla-La Mancha, Spain

QUERO is a wastewater treatment plant located in Quero, a municipality in the province of Toledo, within the autonomous community of Castilla-La Mancha, Spain. The plant serves a population of approximately 5,417 residents, placing it in the small agglomeration category under Spanish and EU regulatory frameworks. The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) and additional polishing steps, ensuring high-quality effluent suitable for discharge into sensitive environments. The treated effluent is discharged into local watercourses that ultimately drain into the Tagus River basin, one of the most important river systems in the Iberian Peninsula. The Tagus River flows westward through Spain and Portugal, emptying into the Atlantic Ocean near Lisbon. The advanced treatment at QUERO helps protect downstream aquatic ecosystems and supports the ecological health of the Tagus basin.

QUERO discharges into the Tagus River basin, which flows through central Spain and Portugal before reaching the Atlantic Ocean. The Tagus is a vital water resource for agriculture, urban supply, and biodiversity, supporting species such as the Iberian barbel and various waterfowl. Advanced treatment at the plant reduces nutrient loads, helping to prevent eutrophication in downstream reservoirs and estuaries.