Assessing Forward Osmosis As Potential Alternative Seawater Desalination Technology

Abstract

Abstract All researches and studies trending to seawater desalination technology, reverse osmosis or nanofiltration, but in this research I tended towards a new technique which is forward osmosis. Forward osmosis (FO) is one of the emerging membrane technologies which has gained renewed interest recently in desalination process, due to its advantages which is less consumption of energy because of low pressure used. The aim of this research makes an effort to investigate the efficiency performance of (FO) technology for extracting water from types of saline waters using as feed solution (FS) and using ammonium bicarbonate (NH4HCO3) as draw solution (DS). Two types of saline water were used: Aqueous solution and real water. The performance of tested membrane was measured in terms of flux rate and salt rejection under different operation conditions: feed solution (FS) concentration (2500-37000) mg/l, draw solution (DS) concentration (39,530-197,650) mg/l and applied pressure (0.5) bar. Experimental results showed that, increasing DS concentration reflect positive effects on both water flux and rejection rate because of increase of DS osmotic pressure. In other hand, increasing of the feed concentration reduced the water flux and rejection rate due to less difference in osmotic pressure. The results demonstrated the performance of FO for synthetic and real water in flux and salt, maximum water flux was 6.6 L/m2.h for synthetic seawater. In the other hand, for real seawater, results showed that maximum water flux was 4.7 L/m2.h, salt rejection was decreased by time from 97 to 94 %. In this study, heating process performed to removal and recovery ammonium bicarbonate from water. In conclusion, the results indicated that FO performance was encouraging and proved that FO system could be a powerful desalination unit for desalting different sources of saline waters at different concentration levels.