Effects of Sludge Retention Time on the Characteristics of Mixed Liquor and Membrane Fouling in Membrane Bioreactor

Abstract:

In the membrane bioreactor (MBR) treating municipal wastewater, the effect of sludge retention time (SRT) on the contents of the extracellular polymeric substances (EPS), tightly bound EPS (TB) and loosely bound EPS (LB) and the ratios of protein and polysaccharide in TB and LB was studied. With the extension of SRT the EPS increased and the ratios of protein and polysaccharide in TB and LB changed. The above changes influenced the charge distribution of bacterial surface, increased the proportion of hydrophilicity and hydrophobicity on the bacterial surface, changed the bacteria from the instable (R-type) to the stable (S-type), decreased the Zeta potential and increased the values of sludge volume index (SVI). The correlation analysis for the main parameters of fouling resistance was performed by SPSS software, and it was found that the correlation coefficient (rp) was -0.818 for Zeta potential, 0.853 for the content of suspended solids in supernatant and 0.832 for relative hydrophobicity, respectively. SRT of the MBR should be controlled below 120 times of the minimum generation-time of dominant bacteria considering the membrane fouling and sludge characteristics.

• Periodical: Advanced Materials Research (Volumes 113-116)
• Pages: 2057-2061
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.113-116.2057
• Online since: June 2010
• Authors: Zhan Ping Cao, Jing Li Zhang, Hong Wei Zhang
• Keywords: Correlation Analysis, Membrane Bioreactor (MBR), Parameters of Membrane Fouling, Sludge Characteristics, Sludge Retention Time (SRT)

References

[1] A. Pollice, G. Laera, D. Saturno and C. Giordano: J Membrane Sci Vol. 317 (2008), p.65.

[2] E. Reid, X. R. Liu and S. J. Judd: Desalination Vol. 219(2008), p.240.

[3] W. Lee, S. Kang and H. Shin: J Membrane Sci Vol. 216(2003), p.217.

[4] Z. W. Wang, Z. C. Wu and S. J. Tang: Water Res Vol. 43 (2009), p.2504.

[5] S. F. Yang and X. Y. Li: Process Biochemistry Vol. 44 (2009), 91.

[6] Z. Ahmed, J. Cho, B. R. Lim, and K. H. Ahn: J Membrane Sci Vol. 287 (2007), p.211.

[7] A. Masse, M. Sperandio and C. Cabassud: Water Res Vol. 40 (2006), p.2405.

[8] K. Ou-Yang and J. X. Liu: J Env Sci Vol. 21 (2009), 1329.

[9] H. W. Wang, X. Y. Li and Q. X. Zhao: Chin Safety Science J Vol. 13 (2003), p.31.

[10] X. Geng, B. Liang, Y. X. Liang and S J Li: Journal of Sichuan University Vol. 34 (2005), p.62.

[11] O. H. Lowry, N. J. Rosebrough and A. L. Farr: Journal of Biology and Chemistry Vol. 193(1951), p.265.

[12] L. Y. Ge, H. W. Wang, L. M. Ma and X. Y. Li: Environmental Chemistry Vol. 25 (2006), p.722.

[13] F. G. Meng: Identification and Characterization of Fouling Behavior in Submerged Membrane Bioreactors (PhD thesis, Dalian University of Technology 2007).

[14] J. Wingengder, T. R. Neu and H. C. Flemming, in: Microbial Extracellular Polymeric Substances: Charactreization, Structure and Function, Berlin Springer (1999).

[15] S. F. Li, C. W. Cui and J. L. Huang: J Harbin Institute of Technology Vol. 39(2007), p.266.

[16] B. M. Wilén, B. Jin and P. Lant: Water Res Vol. 37 (2003), p.2127.

[17] Q. Yang, X. Huang, H.T. Shang and Y Qian: Environmental Science Vol. 27 (2006), p.2344.

[18] F.G. Meng, H. M. Zhang, F. L. Yang and X. W. Zhang: J Membrane Sci Vol. 272 (2006), p.161.

[19] F. Jorand, F. Boue-Bigne, J. C. Block and V. Urbain: Water Sci and Tech Vol. 37 (1998), p.307 Fig. 4 Changes of Sludge Specific Growth Rate with SRT 2 4 6 8 0 5 10 20 30 40 SRT(d)Specific Growth Rate(d -1).