San Martin de Montalban Wastewater Treatment Plant, Castilla-La Mancha, Spain

The San Martin de Montalban wastewater treatment plant is located in the municipality of San Martin de Montalban, Toledo, in the autonomous community of Castilla-La Mancha, Spain. It serves a population of approximately 2,500 residents, classifying it as a small agglomeration under Spanish and EU regulations. The plant employs advanced treatment processes, exceeding the EU Urban Waste Water Treatment Directive's minimum requirement of secondary treatment for agglomerations of this size. This level of treatment ensures high-quality effluent suitable for discharge into sensitive environments. The plant operates under Spain's national water regulations, which transpose EU directives and are enforced by regional authorities. The treated effluent is discharged into local streams that ultimately feed into the Tagus River, one of the Iberian Peninsula's major rivers. The Tagus flows westward through Spain and Portugal, discharging into the Atlantic Ocean near Lisbon. The plant's advanced treatment helps protect the ecological health of the Tagus basin, which supports diverse aquatic life and provides water for agriculture and urban use.

The plant discharges into the Tagus River basin, which drains into the Atlantic Ocean. The Tagus is a vital water resource for central Spain and Portugal, supporting irrigated agriculture, wetlands, and migratory bird populations. Advanced treatment at this plant reduces nutrient loading and protects downstream ecosystems, including the Tagus Estuary, an ecologically sensitive area.