An experimental study to improve the design of brine discharge from desalination plants

An experiment was performed in water resources engineering department laboratory at Lund University of Sweden to investigate the behavior of inclined negatively buoyant jets. Such jets arise when brine is discharged from desalination plants and improved knowledge of their behavior is required for designing discharge systems that cause a minimum of environmental impact on the receiving waters. In the present study, a turbulent jet with a specific salinity was discharged through a circular nozzle at an angle to the horizontal into a tank with fresh water and the spatial evolution of the jet was recorded. In total, 72 experimental cases were carried out where four different initial jet parameters were changed, namely the nozzle diameter, the initial jet inclination, the jet density (or salinity), and the flow rate (or exit velocity). The measurements of the jet evolution in the tank included five geometric quantities describing the jet trajectory that are useful in the design of brine discharge systems. From the data analysis some geometric quantities describing the jet trajectory showed strong correlations. Also, the results confirmed that the new relationships between the parameters can develop the current knowledge for the new plan to design desalination plants outfall. Thus, if the vertical and horizontal distance to the maximum centerline level (or, alternatively, the maximum jet edge level) can be predicted, other geometric quantities can be calculated from the regression relationships that were developed