Villacarriedo Wastewater Treatment Plant, Cantabria, Spain

The Villacarriedo wastewater treatment plant is located in the municipality of Villacarriedo, in the autonomous community of Cantabria, northern Spain. It serves the local population as part of the region's wastewater infrastructure, operating under Spanish and European Union regulations. The plant provides secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this scale. With a designed capacity of 850 m³/day and an average discharge volume of 183.85 m³/day, the facility operates well below its capacity, indicating room for future growth or seasonal variations. The treated effluent is discharged into a local watercourse that ultimately drains into the Cantabrian Sea (Bay of Biscay). This coastal region supports diverse marine life and is an important ecological area. The plant's operation helps protect downstream water quality and the sensitive coastal environment.

The plant discharges into a local river system that flows through the Pas River basin, eventually reaching the Cantabrian Sea near Santander. This coastal area supports diverse aquatic ecosystems, including fish spawning grounds and migratory bird habitats. The secondary treatment provided by the plant reduces organic pollutants and suspended solids, helping to maintain water quality in the downstream environment.