Desalination brine disposal by means of negatively buoyant jets

Desalination plants commonly discharge large quantities of brine wastes into the adjacent coastal waters causing potentially harmful environmental impacts. To increase the effluent dilution prior to impingement on the sea floor, disposal by means of upwards inclined dense (negatively buoyant) jets can be applied. This paper presents an overview of experimental results on inclined negatively buoyant jets, focusing on the impact dilution achieved and illustrating its dependence on the jet inclination and the source characteristics, expressed by the densimetric Froude number F-o. It is shown that, in a stagnant ambient, the impact dilution for a certain discharge angle is well linearly correlated to F-o (for F-o, larger than about 20) and increases with the angle but is not very sensitive to it in the practical range between 30 degrees and 75 degrees. Typical dilutions attained are of the order of 50. The effect of ambient flow is also briefly discussed.