CIGALES Wastewater Treatment Plant, Cigales, Castilla y León, Spain

The CIGALES wastewater treatment plant is located in Cigales, a municipality in the province of Valladolid, within the autonomous community of Castilla y León, Spain. The facility serves a population of approximately 3,600 residents, classifying it as a small agglomeration under Spanish and EU regulations. The plant employs advanced treatment processes, which go beyond the secondary treatment required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. With a designed capacity of 3,600 m³/day and a current discharge volume of 769.95 m³/day, the plant operates well below its capacity, indicating room for future growth. The advanced treatment likely includes nutrient removal to protect sensitive receiving waters. The treated effluent is discharged into the local hydrological network, which ultimately drains into the Duero River basin. The Duero River flows westward through Spain and Portugal, emptying into the Atlantic Ocean at Porto. The advanced treatment helps safeguard the ecological health of the Duero basin, supporting aquatic life and downstream water quality.

The CIGALES plant discharges into the Duero River basin, a major Iberian watershed that flows through Spain and Portugal to the Atlantic Ocean. The Duero supports diverse aquatic ecosystems and is an important migratory corridor for fish species. Advanced treatment at the plant reduces nutrient loads, helping to prevent eutrophication in downstream reservoirs and coastal waters.