A novel submerged rotating membrane bioreactor and reversible membrane fouling control

A novel type of submerged rotating membrane bioreactor (SRMBR), with a rotatable, rounded, flat-sheet membrane module fixed on the axes and moved by an electromotor, was used to treat synthetic sewage. The SRMBR was operated under constant transmembrane pressure (TMP) condition and a standard TMP-step method has been developed to determine critical TMP for assessing reversible fouling. The effects of the rotation speed of the membrane module, ratio of aeration intensity to permeate flux (A/F) and stoppage time in an intermittent permeation cycle on preventing or eliminating reversible membrane fouling were investigated. The results indicated that increasing rotation speed, A/F and stoppage time could help to prevent reversible fouling in the operation. The fouling prevention ability increases proportionately with increasing the three parameters until their critical values are reached after which further increases would have little effects. The critical values for rotation speed, A/F and stoppage time were 60 r.min(-1), 15 and 1 min for every 10-min cycle, respectively.