Castellar del Valles Wastewater Treatment Plant, Castellar del Vallès, Catalunya

The Castellar del Valles wastewater treatment plant is located in Castellar del Vallès, a municipality in the Vallès Occidental comarca of Barcelona, Catalunya, Spain. The plant serves a population of approximately 19,270 people, classifying it as a medium-sized agglomeration under EU regulations. As a Spanish facility, the plant operates under the EU Urban Waste Water Treatment Directive 91/271/EEC, which requires secondary treatment for agglomerations between 10,000 and 150,000 population equivalent. The plant's designed capacity is 1.00 cubic meters per day, indicating a facility sized for the local population. The treated effluent is discharged into the local watershed, which ultimately drains into the Mediterranean Sea via the Llobregat River basin. The plant plays a key role in protecting the region's water resources and downstream ecosystems, including the coastal waters of the Catalan coast.

The plant discharges into the local water system within the Llobregat River basin, which flows into the Mediterranean Sea near Barcelona. The downstream environment supports diverse aquatic life and is an important coastal zone for the region. The plant's treatment helps reduce nutrient and pollutant loads, protecting the ecological health of the river and the marine environment.