Abstract:Flux and membrane fouling of forward osmosis (FO) treating municipal wastewater using seawater as draw solution were investigated. Steady flux and low membrane fouling were achieved when the active layer faced feed solution (AL-FS). After long-term operation with the configuration of AL-FS, both of the membrane surfaces were fouled, but to different degrees. Fouling analysis revealed that fouling of the support layer only contained some silicate from seawater depositing on the surface, and thus was not severe; while a thick fouling layer was found in the active layer, which was the major contributor to the flux decline, and possibly composed of bacteria, organic matters, inorganic colloids and salt scaling. In addition, FO exhibited a high rejection of nutrients, and the concentration of TOC, NH3-N and TP in the diluted seawater were 2.49, 2.46, 0.05mg/L, respectively. This work shows the great potential of FO for wastewater treatment using seawater as the draw solution.