LERIN Wastewater Treatment Plant, Lerín, Navarra, Spain

LERIN is a wastewater treatment plant located in Lerín, a town in the province of Navarra, northern Spain. The facility serves a population of about 4,578 people and operates under Spain's implementation of the EU Urban Waste Water Treatment Directive (91/271/EEC), which requires secondary treatment for agglomerations of this size. The plant provides secondary treatment, which typically involves biological processes to reduce organic matter and suspended solids. Its designed capacity is 6,133 cubic meters per day, and it currently discharges an average of 343 cubic meters per day of treated effluent. As a plant serving fewer than 10,000 people, it falls under the EU category of small agglomerations, where secondary treatment is the standard requirement. The treated effluent from LERIN is discharged into the local watershed, which ultimately drains into the Ebro River basin. The Ebro River is one of the most important rivers in Spain, flowing into the Mediterranean Sea. The plant's operations help protect the ecological health of the Ebro River system and the downstream coastal environment.

LERIN's treated wastewater is discharged into the Ebro River basin, which flows through northeastern Spain and empties into the Mediterranean Sea via the Ebro Delta. The Ebro Delta is an ecologically sensitive area that supports diverse aquatic life, including important bird populations and fish species. The plant's secondary treatment helps reduce nutrient loads and organic pollution, contributing to the overall health of the river and its downstream ecosystems.