Remoaes Wastewater Treatment Plant, Melgaço, Portugal

Remoaes wastewater treatment plant is located in Melgaço, in the Viana do Castelo district of northern Portugal. The facility serves a population of 3,300, classifying it as a small to medium agglomeration under Portuguese and EU regulations. The plant is situated inland, more than 10 km from the coast, and its operations are part of the regional wastewater infrastructure managed by local authorities. The plant provides secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size discharging into freshwater. The designed capacity is 3,477 m³/day, and the current discharge volume is 550.21 m³/day, indicating operational headroom. As a secondary treatment facility, it removes organic matter and suspended solids, meeting the directive's minimum requirements for inland discharges. The treated effluent is discharged into a local watercourse that flows into the Minho River, which forms the border between Portugal and Spain. The Minho River eventually reaches the Atlantic Ocean near Caminha. The plant's operations help protect the Minho River basin, which supports diverse aquatic life and is an important ecological corridor in the region.

The plant discharges into a tributary of the Minho River, which flows into the Atlantic Ocean. The Minho River basin is ecologically sensitive, supporting diverse fish species and riparian habitats. Downstream, the estuary provides critical nursery grounds for marine life. The plant's secondary treatment helps reduce nutrient and organic loads, mitigating eutrophication risks in the river and coastal zone.