Abstract
A membrane bioreactor (MBR) with gravity drain was tested for virus rejection with two coliphages, T4 and f2, which were used as surrogates for human enteric viruses. Virus rejection was investigated by PVDF and PP membrane modules, with the pore sizes of 0.22 and 0.1 μm, respectively. In tap water system, 2.1 lg rejection of coliphage T4 could be achieved by PVDF membrane compared with complete rejection by PP membrane, while for coliphage f2 with smaller diameter, 0.3–0.5 lg rejection of the influent virus was removed by the two membranes. In domestic wastewater system, cake layer and gel layer on the membrane surface changed the cut-off size of the membrane so that there was no significant difference between PP and PVDF for each coliphage. The removal ratios of coliphage T4 and f2 in the MBR were more than 5.5 and 3.0 lg, respectively. Compared with 5.5 lg removal for virus T4 in the MBR system, only 2.1 lg (96.8%–99.9%) removal rate was observed in the conventional activated sludge system with the influent virus concentration fluctuating from 1830 to 57000 PFU/mL. Only 0.8%–22% virus removal was the effect of adsorption to activated sludge, which showed a decreasing tendency with the retention time, while 75%–98% was the effect of virus inactivation by microbial activity. It indicated that the major mechanism of virus removal was not the transfer of viruses from the water phase to the sludge phase but inactivation in the biological treatment process.
Keywords: MBR, model virus, enteric virus, inactivation
Footnotes
Supported by the National Natural Science Foundation of China (Grant No. 50538090), the Opening Foundation of State Key Laboratory of Environmental Aquatic Chemistry Grant (No. 200601) and the Foundation of Renmin University of China (Grant No. 30206.201.301)
Contributor Information
Xiang Zheng, Email: zhengxiang7825@hotmail.com.
JunXin Liu, Email: jxliu@mail.rcees.
References
- 1.Wei D. B., Hu H. Y., Wang L. S. Sanitary system of in reused wastewater. China Water & Wastewater (in Chinese) 2004;20(1):36–39. [Google Scholar]
- 2.Qiu F. G., Wang X. C. Assessment on health effects of viruses in reused wastewater in city. J Environ Health (in Chinese) 2003;20(4):197–199. [Google Scholar]
- 3.Zheng X., Lv W. Z., Yang M., Liu J. X. Evaluation of virus removal in MBR using coliphages T4. Chin Sci Bull. 2005;50(9):862–867. doi: 10.1360/04wb0087. [DOI] [Google Scholar]
- 4.Lv W. Z., Zheng X., Yang M., Liu J. X. Removal efficiency of viruses in simulated hospital wastewater by using a submerged membrane bioreactor. Process Biochemistry. 2006;41:299–304. doi: 10.1016/j.procbio.2005.06.005. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Gunder B., Krauth K. Replacement of secondary clarification by membrane separation-results with plate and hollow fibre modules. Wat Sci Tech. 1998;38(4–5):383–393. doi: 10.1016/S0273-1223(98)00537-X. [DOI] [Google Scholar]
- 6.Steven W. T., Simon J. J., Bob M. Reduction of faecal coliform bacteria in sewage effluents using a microporous polymeric membrane. Water Res. 1998;32(5):1417–1422. doi: 10.1016/S0043-1354(97)00344-8. [DOI] [Google Scholar]
- 7.Krauth K., Staab K. F. Pressurized bioreactor with membrane separation for wastewater treatment. Water Res. 1993;27(3):405–411. doi: 10.1016/0043-1354(93)90040-O. [DOI] [Google Scholar]
- 8.Zheng X., Liu J. X. Mechanism investigation of virus removal in a membrane bioreactor. Wat Sci Tech; Wat Supp. 2006;6(6):51–59. doi: 10.2166/ws.2006.957. [DOI] [Google Scholar]
- 9.Ueda T., Horan N. J. Fate of indigenous bacteriophage in a membrane bioreactor. Water Res. 2000;34(7):2151–2159. doi: 10.1016/S0043-1354(99)00382-6. [DOI] [Google Scholar]
- 10.Shang C., Wong H. M., Chen G. H. Bacteriophage MS-2 removal by submerged membrane bioreactor. Water Res. 2005;39:4211–4219. doi: 10.1016/j.watres.2005.08.003. [DOI] [PubMed] [Google Scholar]
- 11.Britton G. Introduction to Environmental Virology. New York: John Wiley & Sons, Inc; 1980. pp. 300–317. [Google Scholar]
- 12.Berg G. Viral Pollution of the Environment. Boca Raton: CRC Press, Inc; 1983. pp. 141–145. [Google Scholar]
- 13.Li M., Hu H. Y. Revieww of bacteriophages as viral indicators in water. China Water & Wastewater. 2005;21(2):23–26. [Google Scholar]
- 14.Urase T., Yamamoto K., Shinichiro O. Effect of pore size distribution of ultrafiltration membranes on virus rejection in crossflow conditions. Wat Sci Tech. 1994;30(9):199–208. [Google Scholar]
- 15.Madaeni S. S. The application of membrane technology for water disinfection. Water Res. 1999;33(2):301–308. doi: 10.1016/S0043-1354(98)00212-7. [DOI] [Google Scholar]
- 16.Herath G., Yamamoto K., Urase T. Mechanism of bacterial and virus transport through microfiltration membranes. Wat Sci Tech. 1998;38(4–5):489–496. doi: 10.1016/S0273-1223(98)00549-6. [DOI] [Google Scholar]
- 17.Shi J., Yuan Q., Gao C. J. Handbook of Membrane Technology. Beijing: Chemical Industry Press; 2001. pp. 337–339. [Google Scholar]
- 18.Richard L. W. Evidence that microorganisms cause inactivation of viruses in activated sludge. Appl Environ Microbiol. 1982;43(5):1121–1124. doi: 10.1128/aem.43.5.1221-1224.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Nasser A. M., Glozman R., Nitzan Y. Contribution of microbial activity to virus reduction in saturated soil. Water Res. 2002;36:2589–2595. doi: 10.1016/S0043-1354(01)00461-4. [DOI] [PubMed] [Google Scholar]
- 20.Kim T. D., Unno H. The roles of microbes in the removal and inactivation of viruses in a biological wastewater treatment system. Wat Sci Tech. 1996;33(10–11):243–250. doi: 10.1016/0273-1223(96)00426-X. [DOI] [Google Scholar]