Dispersion models for brine discharges from desalination plants of Oman

Desalination of seawater leaves brine waste containing high salt concentration to be disposed of into the environment. For coastal desalination plants, there is no better alternative than to continuously discharge brine into the sea via an outfall. Subsequent motions, mixing and spreading of the brine are important factors in assessing the impact of disposal operations. Modeling studies of the effect of seabed depth profiles upon dispersing brine discharges into the sea are conducted using a two-dimensional advection-diffusion equation. For illustrations, simple depth profiles of a uniformly sloping beach, a vertical beach with a constant water depth and a step beach with a depth change in its profile are used. Solutions are presented graphically by plotting contours of concentration, demonstrating that if the outfall is located close to the beach, the brine plumes spread towards the coastal area. However, it is found that without building a longer outfall, the coastline brine concentration can be drastically reduced by creating a step discontinuity on the seabed depth profile.