SAN AGUSTIN Wastewater Treatment Plant, San Agustín del Guadalix, Comunidad de Madrid

The SAN AGUSTIN wastewater treatment plant is located in San Agustín del Guadalix, a municipality in the Comunidad de Madrid, Spain. Serving a population equivalent of 16,296, the plant is part of the region's wastewater infrastructure, supporting both residential and local industrial needs. As a medium-sized agglomeration, it plays a key role in protecting public health and the environment in the Madrid metropolitan area. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), plants serving agglomerations between 10,000 and 150,000 population equivalents are required to provide secondary treatment as a minimum. In sensitive areas, such as those draining into nutrient-sensitive water bodies, tertiary treatment may be mandated. The plant's treatment processes are designed to meet these regulatory standards, ensuring compliance with Spanish and European water quality objectives. The treated effluent from SAN AGUSTIN is discharged into the local water system, which ultimately drains into the Jarama River, a tributary of the Tagus River. The Tagus River flows westward through Spain and Portugal, emptying into the Atlantic Ocean near Lisbon. This downstream connection highlights the plant's role in safeguarding water quality across regional and international boundaries, supporting aquatic ecosystems and downstream water uses.

The plant discharges into the Jarama River basin, which flows into the Tagus River, one of the Iberian Peninsula's major rivers. The Tagus River supports diverse aquatic life and provides water for agriculture, industry, and drinking water for millions. The watershed is ecologically sensitive, with habitats that rely on consistent water quality. Proper treatment at SAN AGUSTIN helps prevent nutrient pollution and protects downstream ecosystems, including estuarine and coastal areas near the Atlantic Ocean.