Resende Mirao Wastewater Treatment Plant, Resende, Portugal

Resende Mirao is a municipal wastewater treatment plant located in Resende, Viseu District, Portugal. It serves a population of approximately 3,700 residents, classifying it as a small agglomeration under EU regulations. The plant is situated inland, away from coastal areas, and treats wastewater from the local community. 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. The designed capacity is 5,122 cubic meters per day, with an actual discharge volume of 616.90 cubic meters per day, indicating ample reserve capacity. The plant's operations are subject to Portuguese environmental regulations and EU directives. The treated effluent is discharged into a local watercourse that ultimately drains into the Douro River basin, one of the major river systems in the Iberian Peninsula. The Douro River flows westward through Portugal and empties into the Atlantic Ocean near Porto. The plant plays a key role in protecting the water quality of the Douro watershed and downstream ecosystems.

The plant discharges into a tributary of the Douro River, which flows through northern Portugal and Spain before reaching the Atlantic Ocean. The Douro basin supports diverse aquatic life and is important for agriculture and tourism. The secondary treatment helps reduce organic pollutants and nutrients, mitigating eutrophication risks in downstream waters. The region's climate is Mediterranean with Atlantic influences, leading to seasonal variations in river flow that affect dilution capacity.