Frielas Wastewater Treatment Plant - Loures, Portugal

Frielas wastewater treatment plant is a major municipal facility serving the city of Loures in the Lisbon metropolitan area, Portugal. With a population equivalent of 286,000, it is classified as a large agglomeration under EU regulations, requiring advanced treatment to protect sensitive receiving waters. As a large-scale plant, Frielas is expected to meet the requirements of the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates secondary treatment as a minimum and tertiary treatment for discharges into sensitive areas. The plant's designed capacity is 1.00 (likely in cubic meters per day or similar unit), reflecting its role in managing wastewater from a densely populated urban region. The plant's treated effluent ultimately drains into the Tagus River estuary, a major ecological and economic resource that flows into the Atlantic Ocean near Lisbon. The estuary supports diverse aquatic life, including migratory fish species, and is an important habitat for waterbirds. Effective treatment at Frielas helps reduce nutrient and pollutant loads, protecting both the estuary and coastal waters from eutrophication and contamination.

Frielas plant discharges into the Tagus River estuary, which flows into the Atlantic Ocean near Lisbon. The estuary is a vital ecosystem supporting diverse aquatic life, including fish and bird populations, and is subject to nutrient-sensitive conditions. The plant's treatment performance is crucial for maintaining water quality in this ecologically significant coastal zone.