Brine Dispersion Modeling for Short-Term Low-Volume Desalination Plant of Deir Al Balah

Abstract

Desalination of seawater is a promising alternative water source in coastal countries that suffer from depletion in conventional water sources. In Gaza Strip, the regional short-term low-volume (SLTV) seawater desalination plant was considered as an urgent solution to mitigate the suffering from water crisis. The plant will provide about 7.3 million cubic meters per year of freshwater for domestic uses. However, as a product from the reverse osmosis process, huge amount of brine, nearly 8.92 million cubic meters per year, with salinity reaches to 75,000 mg/L will be redirected to seawater. The arbitrary disposal of brine can have potential negative effects on marine ecosystems. To minimize the negative impacts of the rejected brine on marine environment under the change in the seawater characteristics over the four annual seasons, various outfalls configurations were simulated using CORMIX to study the efficiencies of their mixing behavior taking salinity variations as an indicator. The simulation results showed that the fanned-out unidirectional multiport outfall of option (7) is the optimal design configuration, where discharging the produced brine from the regional STLV plant via option (7) can meet the disposal standard at the boundary of regulatory mixing zone (RMZ) in the worst ambient condition of autumn at low astronomical tide by reducing the brine’s excess salinity at the edge of mixing zone to less than 1.25%(488 mg/L) above seawater salinity.