Trillo Wastewater Treatment Plant, Trillo, Castilla-La Mancha, Spain

The Trillo wastewater treatment plant is located in the town of Trillo, within the province of Guadalajara in the autonomous community of Castilla-La Mancha, Spain. It serves a population of approximately 2,215 residents, making it a small-scale municipal facility. The plant is situated inland, away from coastal areas, and its operations are part of the region's water management infrastructure. The plant provides secondary treatment, which is the standard biological treatment level required under the European Union's Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. The treated effluent from the Trillo plant is discharged into a local watercourse, which ultimately drains into the Tagus River basin, one of the major river systems in the Iberian Peninsula. The Tagus River flows westward through Spain and Portugal, emptying into the Atlantic Ocean near Lisbon. The plant's operations contribute to protecting the local aquatic environment and downstream water quality, supporting the ecological health of the Tagus basin.

The Trillo wastewater treatment plant discharges into a tributary of the Tagus River, which is the longest river in the Iberian Peninsula. The Tagus basin supports diverse aquatic life and provides water for agriculture, industry, and human consumption. Downstream, the river flows through the Alcantara reservoir and eventually reaches the Tagus Estuary in Portugal, a vital wetland area for migratory birds. The plant's secondary treatment helps reduce nutrient and organic pollution, mitigating eutrophication risks in the river and its estuary.