Amiais de Baixo Wastewater Treatment Plant, Santarém, Portugal

Amiais de Baixo is a wastewater treatment plant located in the Santarém district of Portugal, serving a population of approximately 3,000 residents. The facility is situated inland, more than 10 km from the coast, and operates as part of the municipal wastewater infrastructure for the region. The plant employs advanced treatment processes, ensuring a high level of effluent quality before discharge. With a designed capacity of 3,300 m³/day and an average daily flow of 500.19 m³/day, the plant operates well below its capacity, indicating room for future growth. As a Portuguese facility, it complies with national regulations that transpose the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates appropriate treatment levels based on population equivalents and receiving water sensitivity. The treated effluent is discharged into local watercourses that ultimately drain into the Tagus River basin, one of the Iberian Peninsula's major river systems. The Tagus River flows westward through Portugal and discharges into the Atlantic Ocean near Lisbon. The plant's advanced treatment helps protect the ecological health of the downstream aquatic environment, supporting biodiversity and water quality in the region.

The plant discharges into local streams that feed into the Tagus River basin, which flows approximately 1,000 km across Spain and Portugal before reaching the Atlantic Ocean near Lisbon. The Tagus estuary is an ecologically sensitive area supporting diverse aquatic life, including migratory fish species and waterbirds. Advanced treatment at this plant helps reduce nutrient and pollutant loads, contributing to the overall health of the downstream river and coastal ecosystem.