Castelo de Vide B Fonte da Vila Wastewater Treatment Plant - Secondary Treatment, Tagus Basin

Castelo de Vide B Fonte da Vila is a municipal wastewater treatment plant located in Castelo de Vide, a town in the Portalegre District of Portugal. The plant serves a population of approximately 900 residents, making it a small-scale facility within the region's sanitation infrastructure. The plant provides secondary treatment, which is the standard biological treatment stage that removes organic matter and suspended solids. With a designed capacity of 1,200 m³/day and an average discharge volume of 150.06 m³/day, the plant operates well below its capacity. Under Portuguese and EU regulations, small agglomerations like this are required to meet secondary treatment standards as per the EU Urban Waste Water Treatment Directive (91/271/EEC). The treated effluent is discharged into the local watershed, which ultimately drains into the Tagus River basin, one of the Iberian Peninsula's major river systems. The Tagus flows westward through Portugal and into the Atlantic Ocean near Lisbon. The plant's operation helps protect the local streams and the downstream aquatic environment from untreated sewage pollution.

The plant discharges into the Tagus River basin, which flows through central Portugal and empties into the Atlantic Ocean at the Tagus Estuary near Lisbon. This estuary is an ecologically important area that supports diverse aquatic life and serves as a critical stopover for migratory birds. The secondary treatment provided by the plant reduces organic pollutants and suspended solids, helping to maintain water quality in the receiving water bodies and downstream ecosystems.