Portel Wastewater Treatment Plant - Portel, Évora, Portugal

The Portel wastewater treatment plant is located in the town of Portel, within the Évora district of Portugal. It serves a population equivalent of 2,800, classifying it as a small agglomeration under Portuguese and EU regulations. The plant is situated inland, away from coastal areas, and its operations are part of the municipal wastewater infrastructure for the region. The plant provides secondary treatment, which is the minimum standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for freshwater discharges from agglomerations of this size. The designed capacity is 3,164 m³ per day, with an average daily discharge volume of approximately 467 m³, indicating a utilization rate well below capacity. This suggests the plant has room to accommodate future population growth or increased flows. The treated effluent is discharged into the local watershed, which ultimately drains into the Guadiana River basin. The Guadiana River flows southward, forming part of the border between Portugal and Spain, before emptying into the Gulf of Cádiz in the Atlantic Ocean. The plant's operations help protect the water quality of this important river system, which supports diverse aquatic life and agricultural activities in the region.

The Portel plant discharges into the Guadiana River basin, a major watercourse in southern Portugal and Spain. The Guadiana River flows through a semi-arid region with significant seasonal variability, supporting irrigated agriculture and wetlands of ecological importance. The plant's secondary treatment helps reduce organic pollution and nutrient loads, protecting downstream water quality in the river and its estuary, which is a critical habitat for migratory birds and fish species.