In this work, the secondary effluent from a coastal sewage treatment plant was used as feed water to investigate membrane fouling control and trace organic compounds (TrOCs) elimination in an electric field assisted membrane filtration system. Four reactors with different applied voltages (0 V, 1.25 V, 2.5 V, 3 V) were continuously operated (Fig. 1). Six trace organic compounds, namely, sulpiride, metoprolol, carbamazepine, roxithromycin, diclofenac, and atrazine were chosen as target TrOCs. When applied 1.25 V voltage, the membrane fouling was alleviated by 22.9%. The Fourier transform infrared (FTIR) spectra curves showed that proteins and humic substances were the main components of the membrane fouling. When applied 2.5 V and 3 V voltages, chlorine and hydroperoxide were detected in the reactors and membrane fouling was mitigated by 40.6% and 70.8%, respectively. The membrane fouling exhibited a porous structure with small amounts of pores and the main foulant on the membrane surface was humic substances. Under the action of electric field force, humic substances aggregated with each other and then formed the porous and hydrophilic cake layer with lower filtration resistance. Electrochemical oxidation and the acidic condition in the reactors inhibited microorganisms’ attachment to the surface of the membrane. Furthermore, the electric field could improve the elimination of target TrOCs by electrooxidation and electrophoretic migration and the best performance of 35.9%~84.8% removal was achieved at 3 V.

Electric field enhanced membrane fouling mitigation and trace organic compounds removal in a membrane filtration system treating secondary effluent of a sewage treatment plant

ACS Fall 2021

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