Conjunctive use of ultrafiltration with powdered activated carbon adsorption for removal of synthetic and natural organic matter

In a combined powdered activated carbon - ultrafiltration (PAC-UF) system, the removal of organic matter and the behavior of membrane fouling were investigated for the treatment of water containing different concentrations of o-dichlorobenzene (DCB) and humic acids as synthetic and natural organic compounds, respectively. The humic acid removal efficiencies were more significantly dependent on the membrane properties than on the PAC dosage during UF. However, the DCB removal efficiencies were affected by the quantity of humic acids present in the feed water as well as the membrane material and PAC dosage. The binding of DCB to humic acids by complexation contributed to a greater DCB removal at a higher humic acid concentration, particularly with the cellulose acetate membrane. Although PAC addition to the UF system was anticipated to improve the membrane flux through removing organic matter by adsorption, instead, the actual flux decreased and more humic acids were deposited on the membranes. Accordingly, it would appear that the aggregation of humic acids, possibly facilitated by PAC adsorption, resulted in more severe fouling at the membrane surface.