Characterization of biofoulants illustrates different membrane fouling mechanisms for aerobic and anaerobic membrane bioreactors

Abstract

Please cite this article as: Y. Xiong, M. Harb, P-Y. Hong, Characterization of biofoulants illustrates different membrane fouling mechanisms for aerobic and anaerobic membrane bioreactors, Separation and Purification Technology (2015), doi: http://dx.doi.org/10.1016/j.seppur. 2015.11.024 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThis study compares the membrane fouling mechanisms of aerobic (AeMBR) and anaerobic membrane bioreactors (AnMBR) of the same reactor configuration at similar operating conditions. Although both the AeMBR and AnMBR achieved more than 90% COD removal efficiency, the fouling mechanisms were different. Molecular weight (MW) fingerprint profiles showed that a majority of fragments in anaerobic soluble microbial products (SMP) were retained by the membrane and some AnMBR systems and can be applied to facilitate the development of appropriate fouling control strategies.

Polarity-Molecular Weight Profile of Extracellular Polymeric Substances in a Membrane Bioreactor: Comparison between Bulk Sludge and Cake Layers

“…The finding of SMP containing lower 100 kDa in our study was consistent with past studies [25,32], in which by using HPSEC-UV detector and RID, they have reported that these substances can be proteins, polysaccharides, humics. The EPS of cake layers contained large MW than the SMP and their MW distribution ranged from to 450 kDa to over 1,100 kDa which was consistent with previous studies, ranging 488 − 3,397 kDa [25]. Especially Xiong et al [25] found that the peak of 488 kDa substances in cake layers gradually shift to 838 kDa in a longer-filtration operation.…”

“…The EPS of cake layers contained large MW than the SMP and their MW distribution ranged from to 450 kDa to over 1,100 kDa which was consistent with previous studies, ranging 488 − 3,397 kDa [25]. Especially Xiong et al [25] found that the peak of 488 kDa substances in cake layers gradually shift to 838 kDa in a longer-filtration operation. This finding is consistent with the phenomena of the larger MW of cake layers than bulk sludge in our study.…”

“…SMP and bound EPS also reportedly play important roles in the initial and late fouling stages, respectively [24], in which the initial fouling (conditioning of membrane) was caused by humics, whereas later fouling was mainly caused by polysaccharides [16]. Furthermore, SMP have a MW distribution of lower 200 kDa while EPS of cake layers obtained a larger MW one (488 − 3,397 kDa) [25]. However, the findings are still limited in information of polarity-molecular weight to trace potential source of foulant in MBR and understanding the development of membrane fouling.…”

Brief review of operation of anaerobic wastewater treatment with membrane bioreactors

“…Comparative research of Xiong et al [29] on the membrane fouling mechanisms of aerobic (AeMBR) and anaerobic membrane bioreactors (AnMBR) showed faster membrane fouling in the AeMBR system. Also the fouling mechanisms in AeMBR and AnMBR systems are different, therefore fouling control strategies for these two systems should be different [29].…”

Anaerobic Membrane Bioreactor Effluent Reuse: A Review of Microbial Safety Concerns

“…In addition to reiterating the potential for variability among pathogenic species, these results also accentuate the potential for improved pathogen removal rates by anaerobic MBRs. Although the reason for observed higher LRVs by anaerobic MBRs is not clear due to the limited number of studies addressing this issue, one potential explanation could be associated with differences in membrane fouling mechanisms observed in aerobic and anaerobic MBRs [124]. These differences are potentially significant given recent observations that membrane biofilms can improve bacterial LRVs and effluent water quality in general [125].…”