THE EFFECT OF AIR BUBBLES FROM DISSOLVED GASES ON THE MEMBRANE FOULING IN THE HOLLOW FIBER SUBMERGED MEMBRANE BIO-REACTOR (SMBR)

Jang, Namjung; Yeo, Younghyun; Hwang, Moonhyun; Vigneswaran, Saravanamuthu; Cho, Jaeweon; Kim, In S.

doi:2006.11.2.91

Environmental Engineering Research 2006;11(2): 91-98. DOI: https://doi.org/10.4491/eer.2006.11.2.091

THE EFFECT OF AIR BUBBLES FROM DISSOLVED GASES ON THE MEMBRANE FOULING IN THE HOLLOW FIBER SUBMERGED MEMBRANE BIO-REACTOR (SMBR)

Namjung Jang¹, Younghyun Yeo¹, Moonhyun Hwang², Saravanamuthu Vigneswaran³, Jaeweon Cho¹, and In S. Kim¹^†

¹Department of Environmental Science and Engineering, Gwangju Institute of Science & Technology (GIST) 1 Oryong-dong, Buk-gu, Gwangju 500-712, Republic of Korea
²Gwangyang Environmental Research Dept., Research Institute of Industrial Scrence & Technology (RIST), # 699 Gumho-dong, Gwangyang 545-090, Republic of Korea
³Environmental Engineering Group, University of Technology Sydney (UTS), PO Box 123, Broadway NSW 2007 Australia

Corresponding Author: In S. Kim ,Tel: +82-62-970-2436, Fax: +82-62-970-2434, Email: iskim@gist.ac.kr

Received: December 7, 2005; Accepted: April 4, 2006.

ABSTRACT

There is a possibility of the production of the air bubbles in membrane pores due to the reduction in pressure during membrane filtration. The effect of fine air bubbles from dissolved gases on microfiltration was investigated in the submerged membrane bio-reactor (SMBR). The R„ir (air bubble resistance) was defined as the filtration resistance due to the air bubbles formed from the gasification of dissolved gases". From the results of filtration tests using pure water with changes in the dissolved oxygen concentration, the air bubbles from dissolved gases were confirmed to act as a foulant and; thus, increase the filtration resistance. The standard pore blocking and cake filtration models, SPBM and CFM, respectively, were applied to investigate the mechanism of air bubble fouling on a hollow fiber membrane. However, the application of the SPBM and CFM were limited in explaining the mechanism due to the properties of air bubble. With a simple comparison of the different filtration resistances, the Rair portion was below 1% of the total filtration resistance during sludge filtration. Therefore, the air bubbles from dissolved gases would only be a minor foulant in the SMBR. However, under the conditions of a high gasification rate from dissolved gases, the effect of air bubble fouling should be considered in microfiltration.

Keywords: Air bubble fouling | MBR | Hollow fiber membrane. Filtration resistance | Microfiltration