Ansiao Wastewater Treatment Plant, Ansião, Portugal - Advanced Treatment Facility

The Ansiao wastewater treatment plant is located in Ansião, Leiria District, Portugal, serving a population of approximately 4,000 residents. The facility provides advanced treatment, ensuring high-quality effluent before discharge. With a designed capacity of 4,705 m³/day and an actual discharge volume of 666.92 m³/day, the plant operates well within its capacity. As a Portuguese facility, the plant operates under the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates secondary treatment for agglomerations of this scale. The advanced treatment level exceeds the minimum requirements, reflecting Portugal's commitment to protecting water quality in sensitive areas. The treated effluent is discharged into local watercourses that eventually drain into the Atlantic Ocean via the Mondego River basin. The plant plays a key role in safeguarding the region's water resources, supporting both ecological health and downstream communities.

The plant's discharge enters local streams that flow into the Mondego River, one of Portugal's major rivers, which empties into the Atlantic Ocean near Figueira da Foz. The Mondego basin supports diverse aquatic life and is important for agriculture and tourism. Advanced treatment helps minimize nutrient loading and protects downstream ecosystems, including estuarine habitats.