CADREITA Wastewater Treatment Plant, Cadreita, Navarra, Spain

CADREITA is a wastewater treatment plant located in Cadreita, Navarra, Spain. It serves a population of approximately 15,733 people, placing it in the medium agglomeration category under EU regulations. The plant is situated in the Ebro River basin, an important agricultural and ecological region in northern Spain. The plant operates with secondary treatment, which is the standard required by the EU Urban Waste Water Treatment Directive (91/271/EEC) for agglomerations of this size discharging into freshwater. It has a designed capacity of 21,583 m³/day and currently discharges 835 m³/day, indicating significant available capacity. Secondary treatment typically involves biological processes to reduce organic matter and suspended solids. The treated effluent is discharged into the local water system, which ultimately drains into the Ebro River and then into the Mediterranean Sea. The Ebro River delta is an ecologically sensitive area supporting diverse aquatic life and important migratory bird populations. The plant's operation helps protect downstream water quality in this vital watershed.

The plant discharges into the Ebro River basin, which flows into the Mediterranean Sea via the Ebro Delta. This delta is a key ecological zone supporting diverse aquatic life and serving as a critical migratory corridor for birds. The secondary treatment provided by the plant helps reduce nutrient and organic loads, protecting downstream water quality in this agriculturally intensive region.