Development of a membrane–carbon cloth assembly for submerged membrane bioreactors to apply an intermittent electric field for fouling suppression

Using carbon cloth as electrodes, a novel concept of a membrane–carbon cloth assembly for submerged membrane bioreactors that suppresses fouling was successfully demonstrated in this study. The carbon cloth in the assembly was used as the anode, and the assembly was placed between two additional carbon cloths, which were used as the cathode. In such a configuration, it was demonstrated with a DC power supply that membrane fouling was suppressed by applying an electric field continuously, and even intermittently. The fouling-suppression performance was found to relate closely with the intensity of the electric field; a stronger electric field better recovers the filtrate flux. This is because a stronger electric force acts on and removes the foulant substances on the membrane surface when a stronger electric field is applied. Furthermore, it was found that the flux changed periodically with time and had the same periodicity as that of the on–off cycle of the intermittent electric field.

► Membrane–carbon cloth assembly was first developed for submerged MBRs.
► Fouling was suppressed by applying an electric field vertically to the assembly.
► The intensity of the electric field determined the extent of the fouling suppression.
► When applying an electric field intermittently, the flux changed with the same cycle.