[Characteristics of aerobic granular sludge membrane bioreactor for wastewater treatment]

Characteristics of aerobic granular sludge membrane bioreactor (MBR) and the membrane fouling were studied with synthetic wastewater. Experimental results showed that COD removal rate could be reached over 96% under the conditions of HRT = 6h, DO 4 - 6 mg x L(-1) and the volumetric load of COD = 7.24 kg x (m3 x d)(-1). When the volumetric load of NH3-N was 0.17 kg x (m3 x d)(-1), the removal rate of NH3-N was about 60%. The variations of the COD/N ratio could not affect the removal of COD and NH3-N. During the stable operation process, MLSS of the reactor was as high as 14 - 16 mg x L(-1), which could conduce simultaneous nitrification-denitrification, as the anoxic and anaerobic microorganisms might be existed in the core of granular sludge. In addition, the membrane flux of MBR of two different configurations of sludge, granular sludge and floccular sludge, was compared. The flux reduction of granular sludge MBR was much lower than that of floccular sludge MBR. Moreover, the membrane permeability of the granular sludge MBR could be regained simply by backwashing with aeration or washing the membrane with water.