Potential of Nanofiltration for Pretreatment of Seawater Desalination in Gaza Strip

Abstract

The groundwater in the Gaza Strip has deteriorated over the past thirty years qualitatively and quantitatively. This deterioration is attributed to seawater intrusion caused by over exploitation of the aquifer, pollution by untreated wastewater, and pollution from various agricultural activities in the sandy areas of the Gaza Strip. Due to the sharp shortage of water and the bad quality of groundwater, brackish and seawater desalination plants were set up all over the Gaza Strip, producing potable water for the population. All plants are applying reverse osmosis (RO) characterized by high quality of permeate and reasonable cost but low recovery and flux. Nanofiltration membranes, the upraising technology competing with RO especially for brackish desalination and seawater pretreatment due to their remarkable advantages (high flux and recovery, and high salt rejection) are potential alternative. The main objective of this study is to test and measure Nanofiltration membranes performance for potential pretreating of seawater prior to RO in desalination using real samples filtered by dead-end labscale system. Further, the most appropriate Nanofiltration membrane in terms of rejection and flux rate will be determined. Two commercial NF membranes, denoted as NF90 and DK were tested on pressure range (10-25) bars. The water samples used were the real sample was taken from beach wells from RO Deir Al Balah desalination plant after pretreatment units in Gaza strip, Palestine. Using NF90 membrane, there was a good result of flux rate having value equal to 1.23 L/m2.hr at operation pressure 25 bar. Under this pressure, the value of removing TDS was 9.32%. Therefore, this pressure was the optimum for NF90 membrane. For DK membrane, there was 10.05% removal efficiency of TDS at 25 bar, and relatively high value of flux rate which is equal to 2.85 L/m2.hr at 25 bar. This implies that the optimal presser of DK was 25bar. This attributes to the high potentiality of applying NF membranes for seawater desalination in Gaza Strip.