Sobreiras Wastewater Treatment Plant, Porto, Portugal

Sobreiras is a wastewater treatment plant located in the Porto parish of Lordelo do Ouro e Massarelos, Portugal. It serves an estimated population of 180,000, classifying it as a large agglomeration under EU regulations. The plant is situated near the Douro River estuary, a major waterway in northern Portugal. As a large agglomeration, Sobreiras is subject to the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires secondary biological treatment for all discharges from agglomerations over 2,000 population equivalents. For sensitive areas, such as estuaries and coastal waters, more stringent tertiary treatment may be required. The plant's designed capacity is 1. The plant's treated effluent is discharged into the Douro River, which flows into the Atlantic Ocean near Porto. The Douro estuary supports diverse aquatic life and is an important ecological corridor for migratory fish species. The plant's location within 50 km of the coast means its discharge can influence coastal water quality, particularly in the nearby Atlantic marine environment.

Sobreiras discharges into the Douro River, which flows into the Atlantic Ocean at Porto. The Douro estuary is a dynamic ecosystem that supports fish, birds, and invertebrates, and serves as a nursery for several marine species. The plant's location near the coast means its treated effluent contributes to the overall water quality of the Atlantic coastal zone, which is important for tourism and fisheries.