S Paio_Nabais Wastewater Treatment Plant, Gouveia, Portugal

S Paio_Nabais is a wastewater treatment plant located in São Paio, Gouveia, in the Guarda district of Portugal. It serves a population of approximately 2,500 people, classifying it as a small agglomeration under the EU Urban Waste Water Treatment Directive (UWWTD). The plant is situated inland, away from coastal areas, and its operations are part of Portugal's national wastewater management infrastructure. The plant provides advanced treatment, which goes beyond the secondary treatment standard required by the EU UWWTD for agglomerations of this size. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) to protect sensitive receiving waters. The plant has a designed capacity of 2,519 m³/day and currently discharges an average of 416.83 m³/day, indicating ample capacity for future growth. The treated effluent is discharged into local watercourses that drain into the Mondego River basin, one of Portugal's major river systems. The Mondego River flows westward to the Atlantic Ocean near Figueira da Foz. The advanced treatment level helps protect the ecological health of the Mondego River and its downstream estuary, which supports diverse aquatic life and is important for regional biodiversity.

The plant discharges into the Mondego River basin, which flows into the Atlantic Ocean. The Mondego River supports a variety of fish species and provides habitat for migratory birds. Advanced treatment at this plant reduces nutrient loads, helping to prevent eutrophication in the river and coastal waters. The region's inland location means the plant's discharge contributes to freshwater quality before reaching the ocean.