Simulating brine plumes discharged into the seawaters

A seawater desalination plant’s reliability and service availability are essential to sustain and allow the continuing development in the arid climate countries. As desalinated seawater is indispensably required at any cost, the conventional disposal method used for a large size desalination plant is to continuously discharge brine waste stream back into the sea via an outfall at some distance from the beach. One major factor in assessing the potential environmental impact of brine discharges from desalination plants is the oscillatory nature of the coastal currents. A model simulation of the long-time brine plumes steadily discharged into the seawaters is presented using a two-dimensional advection-diffusion equation. The model parameters that minimize the impact of brine discharges are discussed.

Seawater desalination has contributed significantly to ensuring a safe, sustainable and adequate water supply for the arid climate countries. As desalination plants carry a large volume of brine wastewater into the sea [1,2,5], environmental impact studies are required to define regulatory strategies on protection and conservation of the marine environment in a sustainable way. In general there is little information available on the impacts of desalination plants on the marine environment [12,13]. Even less data is available to quantify such impacts for regulatory and design purposes [14]. Higher salinity or fluctuations in salinity is expected near the outfall, and a long outfall’s plume is often observed drifting along the coast [3,4]. Environmental risks can be reduced and regulated by restricting the levels of brine at the discharge point using some treatment and recycling technologies or by imposing the maximum criteria (concentration limit) within the coastal Fig. 6. Cmax as a function of Xmax.