Serta Wastewater Treatment Plant, Sertã, Castelo Branco, Portugal

The Serta wastewater treatment plant is located in Sertã, a town in the Castelo Branco district of central Portugal. The facility serves a population of approximately 3,500 people and has a designed capacity of 4,000 m³/day, with a reported discharge volume of 583.56 m³/day. As a secondary treatment plant, it provides biological treatment to reduce organic matter and suspended solids before discharge. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), plants serving agglomerations of this size (2,000-10,000 population equivalent) are required to provide secondary treatment. The plant's capacity utilization appears low, suggesting it may be designed for future growth or seasonal variations. The facility is operated as part of Portugal's municipal wastewater infrastructure, which is regulated by the Portuguese Environment Agency (APA). The plant discharges treated effluent into a local watercourse that ultimately drains into the Tagus River basin, one of the Iberian Peninsula's major river systems. The Tagus River flows westward through Portugal and empties into the Atlantic Ocean near Lisbon. The receiving waters support diverse aquatic life and are important for regional water supply and agriculture.

The Serta plant discharges into a tributary of the Tagus River basin, which flows through central Portugal to the Atlantic Ocean. The Tagus estuary is an ecologically sensitive area supporting migratory birds and fish species. The plant's secondary treatment helps protect downstream water quality in this important watershed, which is used for irrigation and drinking water supply.