Zafarraya Wastewater Treatment Plant: Advanced Treatment in Andalusia, Spain

The Zafarraya wastewater treatment plant is located in the municipality of Zafarraya, in the province of Granada, Andalusia, Spain. It serves a population of approximately 3,500 people, classifying it as a small agglomeration under EU regulations. The plant is situated inland, more than 10 km from the coast, and its treated effluent is discharged into local watercourses. The plant employs advanced treatment processes, which go beyond the secondary treatment standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. Advanced treatment typically includes nutrient removal (nitrogen and phosphorus) to protect sensitive receiving waters. The plant has a designed capacity of 3,500 m³/day and currently discharges 634.37 m³/day of treated wastewater, indicating significant spare capacity. The treated effluent from Zafarraya ultimately drains into the Guadalquivir River basin, which flows into the Atlantic Ocean at the Gulf of Cádiz. The Guadalquivir basin supports diverse aquatic ecosystems and is an important agricultural and ecological resource in southern Spain. The advanced treatment helps protect downstream water quality and biodiversity.

The Zafarraya plant discharges into local streams that are part of the Guadalquivir River basin, one of Spain's major river systems. The Guadalquivir flows through Andalusia and empties into the Atlantic Ocean at the Gulf of Cádiz, supporting wetlands and estuaries that are critical for migratory birds and aquatic life. The advanced treatment level helps reduce nutrient loading, which is important for preventing eutrophication in downstream waters.