Torrao Wastewater Treatment Plant, Torrão, Alcácer do Sal, Portugal

The Torrao wastewater treatment plant is located in the town of Torrão, part of the Alcácer do Sal municipality in the Setúbal district of Portugal. It serves a population of approximately 2,200 residents, reflecting its role as a small-scale municipal facility in the rural Alentejo region. The plant operates with secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations with a population equivalent between 2,000 and 10,000. Its designed capacity of 3,900 m³/day indicates adequate sizing for current and near-future loads. Treated effluent from the plant is discharged into the local watershed, which ultimately drains into the Sado River estuary and the Atlantic Ocean. The Sado estuary is an ecologically important area supporting diverse aquatic life, including migratory birds and fish species, making proper wastewater treatment essential for protecting downstream water quality.

The Torrao plant discharges into the Sado River basin, which flows into the Sado estuary near Setúbal and then into the Atlantic Ocean. The Sado estuary is a productive coastal ecosystem that supports diverse aquatic life, including important fish nurseries and migratory bird populations. Secondary treatment helps reduce organic pollution and protect this sensitive downstream environment.