Enhanced performance of submerged hollow fibre microfiltration by fluidized granular activated carbon

Abstract

The effect of fluidized granular activated carbon (GAC) on membrane filtration performance was investigated using a bench-scale upflow hollow fibre membrane filtration setup under constant flux operation. The membrane fouling tendencies were compared among five different experimental parameters, namely, GAC size, GAC packing amount, hollow fibre spacing, filtration/idle duration, and fluidization/idle duration. The results indicate that larger-sized GAC particles, higher packing amounts and a ratio of hollow fibre spacing to fluidized particle size of approximately 3–5 are most beneficial for fouling control. Unexpectedly, the intermittent filtration (under continuous fluidization) could not further alleviate membrane fouling compared to continuous filtration, possibly due to inefficient interaction of fluidized GAC particles with membrane surface in absence of permeate driving force. To lower energy consumption, the optimization of intermittent fluidization (under continuous filtration) was performed. Results indicate that the nature of the cake layer formed during non-fluidization period determined the membrane fouling development rather than the fluidization time span. Finally, by comparing the membrane permeability, sodium alginate rejection rate, and membrane properties before and after GAC abrasion, the GAC scouring on membrane integrity was negligible.