Vidago Wastewater Treatment Plant, Chaves, Portugal

Vidago wastewater treatment plant is located in the parish of Vidago, part of the municipality of Chaves in the Vila Real district of northern Portugal. The plant serves a population of approximately 3,600 residents, making it a small-scale facility within the region's wastewater infrastructure. The plant employs advanced treatment processes, which exceed the secondary treatment standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a designed capacity of 6,378 m³/day and an actual discharge volume of 600.23 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal demand. The treated effluent is discharged into the local watershed, which ultimately drains into the Douro River basin. The Douro River flows westward through Portugal and empties into the Atlantic Ocean near Porto. The plant's advanced treatment helps protect the water quality of the Douro basin and downstream ecosystems.

The plant discharges into the Douro River basin, one of the major river systems in the Iberian Peninsula. The Douro River flows through Portugal and Spain, supporting diverse aquatic life and providing water for agriculture and human consumption. The advanced treatment at Vidago reduces nutrient and pollutant loads, helping to maintain the ecological health of the river and its estuary, which is an important habitat for fish and migratory birds.