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. 2017 Jun 6;7(1):2895.
doi: 10.1038/s41598-017-03190-1.

Effects of hydraulic retention time on adsorption behaviours of EPS in an A/O-MBR: biofouling study with QCM-D

Xudong Wang  1 , Botao Cheng  2 , Cunrui Ji  2 , Miao Zhou  2 , Lei Wang  3
Affiliations

Effects of hydraulic retention time on adsorption behaviours of EPS in an A/O-MBR: biofouling study with QCM-D

Xudong Wang et al. Sci Rep. .

Abstract

Extra-cellular polymeric substances (EPS) are a major cause of membrane fouling in membrane bioreactors (MBRs). In this study, an anoxic-oxic membrane bioreactor (A/O-MBR) was run continuously for 98 days. The runs were divided into three stages according to hydraulic retention time (HRT) (11.8, 12.5 and 14.3 h, respectively). EPS were extracted from the reactor under the different HRTs. A quartz crystal microbalance with dissipation monitoring (QCM-D) and Fourier transform infrared (FT-IR) were used to study the adherence layer structures and the adsorption behaviours of EPS on the membrane surface. The results indicated that the removal rate of TN was more susceptible to HRT than NH3-N. The observations in the QCM-D suggested that at the lowest HRT (11.8 h), the structure of the adsorption layer is loose and soft and the fluidity was better than for HRTs of 12.5 or 14.3 h. It is likely one of the major reasons for the rapidly blocking of the membrane pores. Furthermore, the higher EPS adherence as analyzed in the QCM-D and EPS concentration could induce a higher osmotic pressure effect, leading to a rapid membrane-fouling rate.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Figure 1
Figure 1
Treatment performance of the A/O-MBR: (a) COD; (b) NH3-N; and (c) TN. □: Influent concentration, ∇: effluent concent ration, and ⚪: removal rate.
Figure 2
Figure 2
The variation of TMP against operation time under different conditions. Yellow area represents the stage I of TMP changes, Blue area represents the stage II of TMP changes, Cyan area represents the stage III of TMP changes.
Figure 3
Figure 3
EPS adherence properties, extracted from the reactor, after runs operated at different HRTs. Frequency shifts (a) and dissipation factors (b) during EPS adsorption to PVDF-coated QCM-D sensors.
Figure 4
Figure 4
Comparison of the fluidity of different EPS extracted from the reactor after runs operated at different HRTs: (a) 11.8 h; (b) 12.5 h; and (c) 14.3 h. Dissipation factors versus frequency shifts during adsorption are shown. S shows the slope of the linear approximation.
Figure 5
Figure 5
FT–IR spectra of the membrane foulants, SMP and EPS.
Figure 6
Figure 6
Change of EPS against operation time. Note: the EPS concentrations were shown in forms of ‘average value ± standard deviation’.
Figure 7
Figure 7
Schematic design of the A/O-MBR.
See this image and copyright information in PMC

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References

    1. Regula C, et al. Chemical cleaning/disinfection and ageing of organic UF membranes: a review. Water Res. 2014;56:325–365. doi: 10.1016/j.watres.2014.02.050. - DOI - PubMed
    1. Dvorak L, Gomez M, Dvorakova M, Ruzickova I, Wanner J. The impact of different operating conditions on membrane fouling and EPS production. Bioresour. Technol. 2011;102:6870–6875. doi: 10.1016/j.biortech.2011.04.061. - DOI - PubMed
    1. Guo W, Ngo HH, Li J. A mini-review on membrane fouling. Bioresour. Technol. 2012;122:27–34. doi: 10.1016/j.biortech.2012.04.089. - DOI - PubMed
    1. Lee DJ, Chen YY, Show KY, Whiteley CG, Tay JH. Advances in aerobic granule formation and granule stability in the course of storage and reactor operation. Biotechnol. Adv. 2010;28:919–934. doi: 10.1016/j.biotechadv.2010.08.007. - DOI - PubMed
    1. Lin H, et al. A critical review of extracellular polymeric substances (EPSs) in membrane bioreactors: Characteristics, roles in membrane fouling and control strategies. J. Membr. Sci. 2014;460:110–125. doi: 10.1016/j.memsci.2014.02.034. - DOI

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