Enhanced membrane fouling control in a hybrid membrane bioreactor with coarse and fine pore sponge pre-filters

Abstract

Membrane Bioreactors (MBR) have several advantages, but membrane fouling is a major disadvantage that prevents them from being widely used. Therefore, in the present study, the sponge was utilized as a pre-filter with coarse and fine pores in successive compartments before the membrane compartment and termed a “Hybrid-Membrane Bioreactor (H-MBR)”. In the present study, Conventional Membrane Bioreactor (C-MBR) and H-MBR were operated under similar operating conditions to evaluate the performance of H-MBR. The C-MBR experienced more frequent fouling within 60 days of operation, whereas in the H-MBR, the fouling was very low and gradual (i.e., 4.6 kPa at the end of 150 days of operation). Because of the low fouling, the need for cleaning was also eliminated for the stipulated operational period. The overall fouling rate of C-MBR and H-MBR was 5.83 kPa/d and 0.03 kPa/d, respectively. Both MBRs were good at organic pollutant removal. Because of the modification made in the present study, the H-MBR showed 14.66 times less cake layer resistance and 30 times less irreversible fouling resistance than the C-MBR. As a result, the H-MBR is effective in reducing both cake layer resistance and irreversible fouling resistance by retaining both cake-forming materials and irreversible foulants.