Miranda do Douro Wastewater Treatment Plant | Secondary Treatment, Douro Basin

The Miranda do Douro wastewater treatment plant is a municipal facility located in Miranda do Douro, Bragança, Portugal. It serves a population of approximately 3,000 people, classifying it as a small agglomeration under Portuguese and EU regulations. The plant is situated in the northeastern region of Portugal, near the border with Spain, within the Douro River watershed. The plant provides secondary treatment, which is the minimum standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for freshwater discharges from agglomerations of this size. The designed capacity is 5,000 m³/day, and the current discharge volume is 500.19 m³/day, indicating operational headroom. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. The treated effluent is discharged into the Douro River basin, which flows westward through Portugal to the Atlantic Ocean at Porto. The Douro River supports diverse aquatic life and is an important ecological corridor. The plant's operation helps protect water quality in the river, which is used for irrigation, recreation, and downstream drinking water supplies.

The plant discharges into the Douro River basin, which drains into the Atlantic Ocean. The Douro River is a major watercourse in the Iberian Peninsula, supporting diverse aquatic ecosystems and migratory fish species. The plant's secondary treatment reduces organic pollution and protects downstream water quality in this ecologically sensitive river system.