LARRABETZU Wastewater Treatment Plant - Larrabetzu, Euskadi, Spain

The LARRABETZU wastewater treatment plant is located in Larrabetzu, a town in the province of Bizkaia, within the autonomous community of Euskadi (Basque Country), Spain. The plant provides advanced treatment for a population equivalent of 2,000, reflecting its role in managing domestic wastewater for this small community. As an advanced treatment facility, LARRABETZU goes beyond secondary treatment to remove nutrients and other pollutants, meeting stringent discharge standards. The plant has a designed capacity of 3,226 m³/day and currently treats an average of 663.36 m³/day, indicating ample capacity for future growth. Under the EU Urban Waste Water Treatment Directive (91/271/EEC), advanced treatment is required for sensitive areas, and this plant's configuration aligns with that framework. The treated effluent is discharged into local watercourses that ultimately drain into the Bay of Biscay via the Nervión River basin. The plant's inland location, more than 10 km from the coast, reduces direct marine impact, but its discharge contributes to the health of the downstream aquatic ecosystem, supporting biodiversity in the region's rivers and estuaries.

The plant discharges into the Nervión River basin, which flows through the Basque Country and empties into the Bay of Biscay. This watershed supports diverse aquatic life, including migratory fish species such as salmon and eels. The advanced treatment helps protect downstream water quality, reducing nutrient loading that could otherwise contribute to eutrophication in the coastal zone.