Research Progress in Membrane Fouling of Membrane Bioreactor

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Frontier of Environmental Science December 2015, Volume 4, Issue 4, PP.99-103

Research Progress in Membrane Fouling of Membrane Bioreactor Fa Tan, Dunqiu Wang†College of Environmental Science and Engineering, Guilin University of Technology, Guilin 541004, China â€

Email: wangdunqiu@sohu.com

Abstract Membrane bioreactor (MBR) has been becoming a popular technology in wastewater treatment due to its advantages with good treatment efficiency. However, membrane fouling prevented its wide application in water treatment. In this paper, the mechanism of membrane fouling was summarized, and the improvement methods were introduced. Operational parameters were emphasized in the running plants. Keywords: MBR; Membrane Fouling; Operational Parameters

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INTRODUCTION

Membrane bioreactor (MBR) is a process, which combines membrane technology and biological treatment in one unit. MBR has been widely used in sewage and industrial wastewater treatment due to its efficient solid-liquid separation under high sludge concentration. However, membrane fouling is the key factor, which restricts its application. The problem of membrane fouling strictly impacts the life cycle of the expensive membrane unit, then the running cost turns very high. Therefore, the research of membrane fouling is very urgent in developing MBR technology.

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MECHANISMS OF MEMBRANE FOULING

Membrane fouling is a proceeding, during which suspended substances or dissolved matters attach on the surface or in the pore of membrane [1]. The membrane fouling might be led by the interaction force, concentration polarization, formation and compression of the block cake, absorption, filtration pore block between the particles and membrane [2].

2.1 Pollutants The composition of treated liquid plays a key role on membrane fouling. Published investigations of membrane fouling show that the macromolecular organic substance are main pollutants of membrane fouling, which contain the polysaccharide and protein content of extracellular polymeric substances (EPS), humic acids, suspended substance, colloid, and soluble substance, etc. [3]. The properties of the above pollutants are also the main reason of membrane fouling. Harada et al [4] found that the filtration performance decreased with the increasing concentration of soluble organic matter. Nagaoka et al [5] have also observed increasing filtration resistance with increasing supernatant total organic carbon. Wisniewski et al [6] concluded that the dissolved fraction of mixed liquor was responsible for 50%-75% of the total fouling resistance. Defrance et al [7] investigated the relative contributions of suspended solids, colloids, and dissolved matter to filtration resistance and concluded that their impact was 65%, 30% and 5%, respectively. Liu et al [8] studied the effect of EPS on short term membrane fouling in submerged membrane bioreactor and found that the membrane fouling was caused by increasing EPS concentration and the protein was the dominant component of the membrane fouling.

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