LUMBRALES Wastewater Treatment Plant, Lumbrales, Castilla y León, Spain

The LUMBRALES wastewater treatment plant is located in the municipality of Lumbrales, in the province of Salamanca, within the autonomous community of Castilla y León, Spain. The plant serves a population of approximately 4,000 people and operates with secondary treatment, which is the standard biological treatment required under the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size. As a secondary treatment facility, LUMBRALES employs biological processes to reduce organic matter and suspended solids, meeting the effluent quality standards set by Spanish regulations. The plant has a designed capacity of 4,000 cubic meters per day and treats an average daily flow of about 466 cubic meters, indicating it operates well below its design capacity. This suggests the plant has room for future growth or seasonal variations. The treated effluent is discharged into local streams that eventually flow into the Duero River, one of the major rivers in the Iberian Peninsula. The Duero River basin supports diverse aquatic ecosystems and is an important water resource for agriculture and human consumption. The plant's secondary treatment helps protect the water quality of these downstream environments, contributing to the ecological health of the basin.

The LUMBRALES plant discharges into small tributaries of the Duero River, which flows westward through Spain and Portugal before emptying into the Atlantic Ocean at Porto. The Duero basin is ecologically significant, supporting species such as the Iberian barbel and the endangered European eel. The plant's secondary treatment reduces organic pollution, helping to maintain water quality in this sensitive river system that is used for irrigation and drinking water supply downstream.