Fouling with aerobic granule membrane bioreactor

Abstract

Aerobic granulation (AG) and membrane bioreactor (MBR) are two promising, novel environmental biotechnological processes that draw interest of researchers working in the area of biological wastewater treatment. Membrane fouling in the combined aerobic granular membrane bioreactor (AGMBR) process and the conventional MBR process was investigated in this work. The irreversible fouling on hollow-fibre membranes in both reactors were observed with the multiple staining and confocal laser scanning microscope technique. Following physical and chemical washing, the external fouling layers were mostly removed. However, the biofilms built up in the interior surface of membrane remained and contributed to the irreversible fouling resistance. AGMBR retained most cells with granules, thereby reducing their penetration through membrane and thus the chance to form internal fouling layer. The internal biofilm layer was principally composed of live cells embedded in a matrix of proteins and polysaccharides, with that on AGMBR denser and thicker than that on MBR. Prevention of development of internal biofilm is essential to reduce irreversible fouling of AGMBR and MBR membranes.

Membrane Bioreactor (MBR) Technology for Wastewater Treatment and Reclamation: Membrane Fouling

“…The presence of both hydrophobic and hydrophilic groups in EPS implies that they are amphoteric in nature. Since the hydrophilic fraction is known to foul the membrane (hydrophilic membrane) more than the hydrophobic fraction, the proportion of hydrophobic to hydrophilic organics plays an important role in the formation of fouling [ 105 ]. Thus, the ratio of proteins (hydrophobic) to polysaccharides (hydrophilic) in EPS governs membrane fouling in MBRs, especially cake layer formation [ 12 ].…”

“…Another study by Juang et al [ 105 ] investigated membrane fouling in AGMBR and reported that most bacteria cells were retained by the granules thus preventing their penetration through the membrane pores and the chance to cause internal fouling layer. The combination of aerobic granulation and MBR has also been reported to enhance good filtration performance and lower propensity for membrane fouling [ 115 ].…”