Forward osmosis desalination from laboratory to market

Abstract

A two-step forward osmosis (FO) desalination process combining both FO and reverse osmosis (RO) systems has been developed by the Centre for Osmosis Research and Applications at the University of Surrey and commercialised by Modern Water plc. In the FO + RO process seawater was used as feed water (FW) and a concentrated aqueous solution was used as a draw solution (DS). By taking advantage of natural osmosis, pure water is transferred from the FW to the DS and then recovered from the DS by the RO process utilising low resistance membranes, and hence lower specific energy consumption (SEC). This paper presents results of FO experiments conducted on flat sheet membrane using a bench-scale rig. The osmotic agent investigated in this study was magnesium sulphate, which is non-toxic, and highly soluble in water. Furthermore experiments were carried out on the RO pilot in order to regenerate the DS for reuse in the FO process and produce clean water. This paper also presents some pilot plant results and data from commercial plants in Oman and Gibraltar. The data demonstrates the efficiency of the FO + RO compared with the conventional RO process in terms of SEC and membrane fouling performance.

Forward Osmosis Membrane: Review of Fabrication, Modification, Challenges and Potential

“…In Oman, the 100 m 3 /h capacity of the FO plant is installed at Al Khaluf near the Arabian Sea by Modern Water Company and used for Arabian seawater desalination for drinking water purposes. After 35% water recovery to dilute the DS by FO, the dilute DS is desalinated by RO to produce potable water (TDS: 120 mg/L) [192]. Within the next decade, I anticipate that the technology will take off into the market as more and more companies begin to incorporate it into their water purification systems.…”

Removal Efficiency of Solid Particles from Raw Water Using AFM Grade-2 Media: Case Study

“…Membrane fouling is broadly categorized into colloidal, organic precipitation and biological fouling. All these types of fouling require their own specialized pre-treatment operations [6,7]. Scale formations on RO membrane may occur when sparingly soluble salts in the RO feed water are concentrated beyond their solubility.…”