GRAUS Wastewater Treatment Plant, Graus, Aragón, Spain

GRAUS is a wastewater treatment plant located in Graus, a town in the Ribagorza comarca of Huesca province, Aragón, Spain. The plant serves a population of 5,341 and is an integral part of the municipal wastewater infrastructure for the area. The plant employs advanced treatment processes, ensuring a high level of effluent quality. Its designed capacity is 7,200 cubic meters per day, with an actual discharge volume of 968.04 cubic meters per day, indicating ample capacity for current loads. As a Spanish facility, it operates under the national transposition of the EU Urban Waste Water Treatment Directive (91/271/EEC), which mandates secondary treatment for agglomerations of this size, and the plant exceeds this requirement with advanced treatment. The treated effluent is discharged into a local watercourse that ultimately drains into the Ebro River, one of Spain's major rivers. The Ebro basin supports diverse aquatic ecosystems and is important for agriculture and biodiversity in the region. The plant's advanced treatment helps protect downstream water quality and ecological health.

The plant discharges into a tributary of the Ebro River, which flows into the Mediterranean Sea via the Ebro Delta. The Ebro basin is a critical water resource for northeastern Spain, supporting irrigated agriculture and wetlands. The delta is an ecologically sensitive area that provides habitat for numerous bird species and aquatic life. Advanced treatment at GRAUS reduces nutrient loads and pollutants, helping to mitigate eutrophication risks in the river and coastal waters.