Evaluation of the impact of brine discharge position on salinity in the Persian/Arabian Gulf’s slow flushing zone (original) (raw)

DESALINATION AND WATER TREATMENT

The Persian/Arabian Gulf is the sink of hypersaline effluent (brine) for plants with about half of the world's seawater desalination capacity. Many of these plants discharge brine into the Gulf's southwestern region where the salt in brine accumulates because seawater there is not replaced often by the Gulf's residual circulation (i.e., the region is poorly flushed). This circulation flushes the whole Gulf and inhibits salt accumulation at the basin scale. But flushing is not effective in the southwestern region, which has been described as the "Gulf's slow flushing zone." Here, the impact of brine discharge position on salinity in this zone is evaluated by comparing two scenarios of brine discharge into the Gulf's residual circulation dynamics. In the first scenario, brine from the 24 largest seawater desalination plants in the Gulf is introduced into the residual circulation; and in the second scenario, the brine discharge position of one of these 24 plants is positioned away from the slow flushing zone. In the two scenarios, brine discharge caused salt buildup in the slow flushing zone. However, annual area-average salinity there is about 1.10-1.55 PSU smaller in scenario two compared to scenario one, indicating the influence of discharge position on salt buildup because of brine discharge. This study, accordingly, suggests a methodology for selecting brine discharge position in the Gulf's slow flushing zone.