ARENAS DE IGUNA Wastewater Treatment Plant, Cantabria, Spain

ARENAS DE IGUNA is a wastewater treatment plant located in the Barrio de la Molina, San Juan de Raicedo, in the municipality of Arenas de Iguña, Cantabria, Spain. Serving a population of 236, this facility is designed to handle a capacity of 20,000 cubic meters per day, indicating it is sized for future growth or seasonal peaks. The plant operates with advanced treatment, ensuring high-quality effluent before discharge. As a Spanish wastewater facility, ARENAS DE IGUNA operates under the national regulations that transpose the EU Urban Waste Water Treatment Directive (91/271/EEC). For small agglomerations (under 2,000 population equivalent), the directive requires appropriate treatment, and Spain's implementation ensures compliance with secondary or equivalent standards. The advanced treatment level at this plant exceeds the minimum requirements, providing additional nutrient removal or disinfection. The plant's treated effluent is discharged into the local water system, which ultimately drains into the Cantabrian Sea via the Besaya River basin. The region's rivers support diverse aquatic life and are important for local ecosystems. The advanced treatment helps protect downstream water quality and the marine environment of the Bay of Biscay.

The plant discharges into the Besaya River basin, which flows northward through Cantabria and empties into the Cantabrian Sea (Bay of Biscay). This coastal region supports diverse marine and estuarine habitats, including important fisheries and migratory bird routes. Advanced treatment at this facility reduces nutrient and pollutant loads, helping to maintain the ecological health of the downstream river and coastal waters.