Gosundeira Wastewater Treatment Plant, Sobral de Monte Agraço, Portugal

Gosundeira is a wastewater treatment plant located in Cabeda, Sobral de Monte Agraço, in the Lisbon district of Portugal. The plant serves a population of approximately 4,300 people, placing it in the small agglomeration category under EU regulations. It is situated inland, more than 10 km from the coast, and treats wastewater from the local community. The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. The designed capacity is 5,033 m³/day, with a current discharge volume of 716.94 m³/day, indicating ample capacity for future growth. The plant's operational status is active, and it is part of Portugal's national wastewater infrastructure managed under the country's water resources framework. The treated effluent is discharged into local watercourses that eventually drain into the Atlantic Ocean via the Tagus River basin. The plant plays a key role in protecting the region's water quality, supporting aquatic ecosystems, and preventing nutrient pollution in downstream environments. Its advanced treatment ensures compliance with stringent European standards for sensitive areas.

The plant discharges into small streams that feed into the Tagus River basin, which flows westward to the Atlantic Ocean near Lisbon. The Tagus estuary is a vital ecological zone supporting diverse aquatic life, including migratory fish and bird species. Advanced treatment at Gosundeira helps reduce nutrient loads and protects downstream water quality in this ecologically sensitive region.