Comparing four mixing zone models with brine discharge measurements from a reverse osmosis desalination plant in Spain

Nuevo Canal de Cartagena (Spain) desalination plants discharge hypersaline effluent through a submarine outfall pipeline, creating a negatively buoyant brine jet. Many near-field mixing models are used in the prediction and management of brine discharges, but they have rarely been compared with field salinity measurements obtained directly inside the brine jet. Two divers obtained these field measurements and compared them with CORMIX1, CORJET, MEDVSA and UM3 mixing zone model predictions. In general, each model was quite conservative in its results, except UM3, whose prediction presented the best approximation to measured data. It is concluded that direct field measurements should be essential when testing the accuracy of current models or developing new near-field mixing models.

► Brine jet dilution process in the near-field was registered in-situ by divers.
► Field measurements indicated that CORMIX1, CORJET and MEDVSA were conservative models.
► UM3 was the most realistic model.
► In-situ measurements should be essential when testing mixing models.