LOGRONO Wastewater Treatment Plant, Logroño, La Rioja, Spain

The LOGRONO wastewater treatment plant is located in Logroño, the capital of La Rioja, Spain. It serves a population of approximately 221,218, classifying it as a large agglomeration under EU regulations. The plant is situated near the Iregua River, a tributary of the Ebro River. As a large agglomeration, the plant is required to meet secondary treatment standards under the EU Urban Waste Water Treatment Directive (91/271/EEC). Depending on the sensitivity of the receiving waters, tertiary treatment may also be mandated to reduce nutrients. The plant's capacity and treatment processes are designed to handle the wastewater from the urban area and surrounding communities. The treated effluent is discharged into the Iregua River, which flows into the Ebro River, eventually reaching the Mediterranean Sea. The Ebro River basin supports diverse aquatic life and is an important ecological corridor in northeastern Spain. Proper treatment helps protect water quality and downstream ecosystems.

The plant discharges into the Iregua River, a tributary of the Ebro River, which flows into the Mediterranean Sea. The Ebro basin is ecologically significant, supporting diverse aquatic species and providing habitat for migratory birds. Nutrient removal is critical to prevent eutrophication in the Mediterranean coastal zone.