Castro Verde Wastewater Treatment Plant - Beja, Portugal

The Castro Verde wastewater treatment plant is located in the municipality of Castro Verde, Beja district, Portugal. It serves a population of approximately 5,900 residents, making it a small to medium agglomeration under Portuguese and EU classification. The plant is situated inland, away from coastal areas, and treats municipal wastewater from the local community. The facility 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. With a designed capacity of 6,300 m³/day and an average discharge volume of 983.71 m³/day, the plant operates well within its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into the local watershed, which ultimately drains into the Atlantic Ocean via the Sado River basin or nearby tributaries. The region is characterized by a Mediterranean climate with hot, dry summers and mild, wet winters. The plant's advanced treatment helps protect downstream water quality and supports the ecological health of the receiving water bodies.

The Castro Verde plant discharges into the Sado River basin, which flows westward into the Atlantic Ocean near Setúbal. The Sado estuary is an ecologically sensitive area supporting diverse aquatic life, including migratory fish and bird species. Advanced treatment at the plant reduces nutrient loads and pollutants, helping to maintain water quality in the river and downstream coastal waters.