2002 Fiscal Year Final Research Report Summary
Transition of the hygienic safety at the time of the membrane module breakage in a membrane separation process
| Project/Area Number |
13650609
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Civil and environmental engineering
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| Research Institution | Kisarazu National College of Technology |
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Principal Investigator |
TAKAHASHI Katsuo Kisarazu National College of Technology, Kisarazu National College of Technology, Civil Engineering, Professor (20005490)
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| Co-Investigator(Kenkyū-buntansha) |
SHINICHIRO Ohgaki The University of Tokyo, Urban Engineering, Professor (20005549)
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| Project Period (FY) |
2001 – 2002
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| Keywords | membrane-separated activated sludge / microfiltration / follow fiber membrane / coliphages / fecal coliforms |
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| Research Abstract |
Removal efficiency of coliphages and fecal coliforms in a membrane separation activated sludge process and a conventional activated sludge process was investigated. A hollow fiber MF membrane with nominal pore size of 0.4μm was used in this study. The average removal efficiency of RNA phages was 5.01Log in the membrane separation-activated sludge process while 2.59Log in the activated sludge process, indicating that the removal in the membrane separation-activated sludge process was 3.10Log higher than that in the activated sludge process.
Coliphage that are smaller than the membrane pore size were also removed in the membrane separation-activated sludge process.
It was suggested that the membrane separation-activated sludge process has a superior hygienic safety against bacteria and virus than that of the activated sludge process.
The followings could be drawn from the experiment with 2% of the membrane module breakage.
The turbidity, fecal coliforms, and RNA phages of the effluent before the breakage were 0.15 NTU, 1 CFU/mL and non-detectable, respectively, while those after the breakage increased up to 8.53 NTU, 120 CFU/mL, and 1.3 PFU/mL. Afterwards, those indicators tended to decrease with time, suggesting that just after the breakage hygienic safety temporarily lowered.
The determination of turbidity was found to be effective to detect the breakage of membrane.
On the other hand, the experiment with coliphage Qβ showed that there was a 2.3Log removal difference between the normal and the broken membrane, indicating that the detection and safety measures of membrane fracture are required in the operation of membrane separation process.
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