Quinta do Seixo Wastewater Treatment Plant, Trancoso, Portugal

Quinta do Seixo is a wastewater treatment plant located in Trancoso, within the Guarda district of Portugal. It serves a population of approximately 2,000 people, making it a small-scale municipal facility. The plant is situated inland, away from coastal areas, and its operations are integral to local sanitation infrastructure. The plant provides secondary treatment, which is the standard biological process required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Secondary treatment effectively removes organic matter and suspended solids, ensuring that the effluent meets quality standards before discharge. The plant has a designed capacity of 2,000 cubic meters per day, matching the population served, and reports a discharge volume of 333.46 cubic meters per day. Treated wastewater from Quinta do Seixo is discharged into local streams that eventually flow into the Douro River basin, one of the major river systems in the Iberian Peninsula. The Douro River drains into the Atlantic Ocean near Porto, supporting diverse aquatic ecosystems along its course. The plant's operations help protect downstream water quality and contribute to the ecological health of the region.

Quinta do Seixo discharges into small watercourses within the Douro River basin, which flows westward through northern Portugal and Spain before reaching the Atlantic Ocean. The Douro basin supports a variety of freshwater habitats and is important for migratory fish species. The plant's secondary treatment helps reduce nutrient and organic pollution, safeguarding the ecological balance of these waters.