RIO ASON Wastewater Treatment Plant, Rasines, Cantabria, Spain

RIO ASON is a wastewater treatment plant located in the municipality of Rasines, in the autonomous community of Cantabria, northern Spain. The plant serves the local population and is situated in the Asón River valley, an area known for its natural landscapes and proximity to the Bay of Biscay. The plant employs advanced treatment processes, which go beyond secondary treatment to remove nutrients and other pollutants. With a designed capacity of 7,200 m³/day and a current discharge volume of 811.82 m³/day, it operates well below its capacity. As a Spanish facility, it complies with the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires advanced treatment for sensitive areas and agglomerations over 10,000 population equivalent. The treated effluent is discharged into the Asón River, which flows northward through Cantabria and into the Bay of Biscay (Atlantic Ocean). The river supports diverse aquatic life and is an important ecological corridor. The plant's advanced treatment helps protect the coastal and marine environment from nutrient pollution.

The plant discharges into the Asón River, which flows through the Cantabrian region and empties into the Bay of Biscay. The river supports a variety of fish and wildlife, including salmon populations. The coastal waters are ecologically sensitive, and advanced treatment helps reduce nutrient loads that could cause eutrophication in the marine environment.