Investigation of HRT effects on membrane fouling in sequencing batch membrane bioreactor with respect to batch filtration mode

Membrane fouling in sequencing batch membrane bioreactor (SBMBR) was studied with respect to batch filtration mode at the two hydraulic retention times (HRT) of 16 h (SBMBR1) and 48 h (SBMBR2). Investigating the characteristics of batch filtration phases illustrated different TMP (Transmembrane Pressure) changing trends at the two HRTs. In SBMBR1, TMP rising rates per cycle were remarkably high and represented an increasing trend versus the filtration number, while in SBMBR2, TMP rising rates per cycle were comparatively low and did not change much with increase of the number of filtration. Larger particle sizes of the bulk sludge resulted in formation of a reversible cake layer on the membrane surface in SBMBR1. In the contrary, smaller particle sizes of the bulk sludge in SBMBR2 induced an internal pore blocking of the membrane, which was less reversible. In addition to cake layer formation, higher SMP content of the bulk sludge along with the accelerating effect of the higher filtration frequency resulted in the higher values of TMP rising rate per cycle in SBMBR1. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1785–1793, 2017