Membrane Fouling in Aerobic Granular Sludge Membrane Bioreactor

The effect of aerobic granular sludge on membrane fouling in the membrane bioreactor was studied.The operation time of aerobic granular sludge membrane bioreactor is increased to 36 days,compared to 19 days for floc sludge MBR.The experiment on granular sludge in the sludge cake shows that the ratio of floc sludge to total sludge is 56.2%,which is larger than 45.8% in the mixed liquor.Furthermore,the specific resistance of floc sludge in the cake is 15.81×1012 m/mg,while the specific resistance of granular sludge with particle size larger than 1.6 mm is only 0.47×1012 m/mg.It is observed that protein is a major component of EPS in the sludge cake,and EPS content in the sludge cake is larger than that in the mixed liquor,both floc sludge and granular sludge.