Comparison of pretreatment methods for wastewater reclamation and seawater desalination in forward osmosis process

Abstract

Forward osmosis (FO) has drawn attention as an emerging technology for seawater desalination and wastewater treatment/reuse. Nevertheless, little information is available on the selection of proper pretreatment for FO process. Accordingly, this study focused on the comparison of different pretreatment methods for FO to provide into the selection of its pretreatments. Two groups of pretreatment methods were compared: membrane-based pretreatments including microfiltration and ultrafiltration and conventional filtration using activated filter media. Experiments were conducted to explore correlations between the silt density index/modified fouling index and FO flux decline. The Hermia’s model equations were applied to analyze the results and to identify the dominant fouling mechanisms. The possibility of using a fouling index to predict FO fouling was also examined.