Performance of Nanofiltration-Like Forward-Osmosis Membranes for Aerobically Treated Palm Oil Mill Effluent

For the first time, engineered osmosis was performed using commercial nanofiltration (NF) membranes for the treatment process of aerobically treated palm oil mill effluent (AT-POME). Compared to conventional forward-osmosis (FO) membranes with dense rejection layer, the NF-like FO membranes offer a higher water flux with minimum reverse solute flux provided appropriate solutes like divalent salts or polyelectrolytes were used in the draw solution. Both NF membranes were able to treat the AT-POME by completely preventing the color component from passing through the permeate side under FO and pressure-retarded osmosis (PRO) orientation. The water fluxes of the membranes were higher under PRO orientation owing to the reduced internal concentration polarization effect. Relatively loose membranes for the engineered osmosis application could address severe surface fouling of membranes tested under pressure-driven filtration.