Porto Alto Pendente II Wastewater Treatment Plant, Samora Correia, Portugal

Porto Alto Pendente II is a municipal wastewater treatment plant located in Samora Correia, Benavente, Santarém District, Portugal. The facility serves a population of approximately 2,500 people and is situated in the Porto Alto area, near the EN 118 road. Its coastal proximity places it within the sensitive estuarine zone of the Tagus River. The plant provides secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The designed capacity is 3,500 m³/day, and the current discharge volume is about 417 m³/day, indicating operational headroom. The facility operates under Portuguese national regulations that transpose EU directives, overseen by the Portuguese Environment Agency (APA). The treated effluent is discharged into the local drainage network that ultimately reaches the Tagus River estuary, a major Atlantic coastal ecosystem. This estuary supports diverse aquatic life and is an important migratory corridor for birds. The plant's performance is critical for protecting water quality in this ecologically sensitive area, which is subject to nutrient enrichment pressures from agriculture and urban runoff.

The plant discharges into the Tagus River basin, which flows into the Tagus estuary and then the Atlantic Ocean near Lisbon. The estuary is a highly productive ecosystem that supports diverse fish and bird species, including migratory waterfowl. As a coastal plant within 10 km of the coast, its secondary treatment effluent contributes to nutrient loads that can affect estuarine water quality and marine habitats.