The factors affecting the performance of the FO-RO hybrid system

Abstract

Forward osmosis (FO) and reverse osmosis (RO) hybrid process provides an opportunity for safe and beneficial reuse of wastewater also it provides a pre-treatment step for RO desalination. We investigated the influence of different parameters (draw solution concentration, cross-flow velocity rates, feed water pH and types of membranes and their properties and the applied pressure) on the FO process during the osmotic dilution of seawater as part of the simultaneous desalination and wastewater reuse by FO and RO hybrid system. Synthetic wastewater (SWW), containing combined organic and inorganic foulants, was used as the FS. The interactions between foulants and membrane were examined by using the CTA membrane and the TFC membrane. Membrane materials play an important role in the membrane-foulant interactions consequently on controlling membrane fouling and cleaning behavior in the FO process. Moreover, the elevated DS concentration boosts fouling of the FO membrane and diminishes cleaning efficiency. It was found that the cross-flow velocity was the dominant factor governing FO membrane fouling as the increase in the cross-flow velocity result in less fouling.