Atouguia_Abrigada Wastewater Treatment Plant, Alenquer, Portugal

Atouguia_Abrigada is a wastewater treatment plant located in the parish of Atouguia das Cabras, Abrigada e Cabanas de Torres, in the municipality of Alenquer, Lisbon District, Portugal. The plant serves a population of approximately 2,100 people, classifying it as a small agglomeration under Portuguese and EU regulations. The plant provides secondary treatment, which is the minimum standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for discharges into freshwater and estuaries from agglomerations of this size. The designed capacity is 2,357 cubic meters per day, with a reported discharge volume of 350.13 cubic meters per day, indicating operational headroom. The treated effluent is discharged into the local watershed, which ultimately drains into the Tagus River, one of the Iberian Peninsula's major rivers. The Tagus River flows westward through Portugal and into the Atlantic Ocean near Lisbon. The plant's operations help protect downstream water quality and aquatic ecosystems in the Tagus basin.

The plant discharges into the Tagus River basin, which flows into the Atlantic Ocean at the Tagus Estuary near Lisbon. The estuary is an ecologically sensitive area that supports diverse aquatic life, including migratory fish species and waterbirds. Secondary treatment helps reduce organic pollutants and suspended solids, mitigating eutrophication risks in the receiving waters.