科研之友
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摘要
Currently, polyvinylidene fluoride (PVDF) membranes are widely used because of their chlorine resistance and durability. However, membrane bioreactor (MBR) processes still have obstacles to overcome to be cost effective for wastewater treatment. To overcome these obstacles, stable, long-term operations of MBRs with high permeate flux and low membrane fouling are strongly desired. In this study, both a lab and a pilot scale membrane system with new polytetrafluoroethylene (PTFE)-based flat sheet membrane modules were operated to monitor the effectiveness of chemical backwashing for membrane fouling control. There were two operation modes in the lab experiment. One (MBR2) was applied by chemical backwashing once a day and the other (MBR1) was operated without chemical backwashing. The transmembrane pressure (IMP) remained stable in MBR2 after 25 days, while the TMP increased continuously and eventually reached the upper limit in MBR1. The R-t (total resistance), R-c (cake resistance) and R-f (fouling resistance) of both MBR1 and MBR2 were 8.88 x 10(11) m(-1), 3.52 x 10(11) m(-1), 4.07 x 10(11) m(-1) and 5.34 x 10(11) m(-1), 2.10 x 10(11) m(-1), 1.91 x 10(11) m(-1), respectively, after 30 days of operation. In the pilot scale test, chemical backwashing had similar effects on R-f, but minimal influence on the control of R. Chemical backwashing was effective for controlling R-f, but there were differences in R-c reduction by aeration according to membrane position. High quality effluent from filtration indicated that the activity of the microorganisms had not been harmed by chemical backwashing. Through lab and pilot scale experiments, it was confirmed that using a FIFE flat sheet membrane with chemical backwashing in an MBR system could provide high flux, twice as much as that from a conventional system. In conclusion, FIFE membranes have significant potential as next generation membrane materials replacing the currently used PVDF membranes, and chemical backwashing will compensate for the weaknesses associated with the use of flat sheet membranes in field applications.
- 出版日期2012-11-15
