1991 Fiscal Year Final Research Report Summary
Water purification in membrane separation rejection of bacteria and virus and factors effecting permeate flux.
| Project/Area Number |
02453051
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
都市工学・衛生工学
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| Research Institution | The University of TOKYO |
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Principal Investigator |
HUJITA Kenji The University of Tokyo, Department of Urban Engineering. Professer., 工学部, 教授 (40107529)
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| Co-Investigator(Kenkyū-buntansha) |
KANEKO Hidehiro The University of Tokyo, Department of Urban Engineering. Research Associate., 工学部, 助手 (60177524)
YAMAMOTO Kazuo The University of Tokyo, Department of Urban Engineering. Associate Professer., 工学部, 助教授 (60143393)
OHGAKI Shinichiro The University of Tokyo, Department of Urban Engineering. Professer., 工学部, 教授 (20005549)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Water purification / membrane separation / virus removal / bacteria removal / microfiltration / ultrafiltration / permeate flux / hollow filter membrane |
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| Research Abstract |
It is important to elucidate the characteristics of membrane filtration and separation to know feasibility and applicability of membrane technology in water purification. In this research, rejection of bacteria and virus was investigated as well as removal of turbid and colloidal materials. Factors affecting permeate flux was also studied. The results obtained are summarized as below.
1) The removals of kaolin suspensions, humic substances and E. coli groups by externally pressurized hollow fiber microfiltration membrane (30 nm of pore size) were almost the same as those by tubular ultrafiltration membrane (14, 000 dalton of molecular weight cut off size). The permeate flux of hollow fiber module used ranged from 2.5 to 6 m/d and it was high enough for practical application.
2) By using latex particles for artificial cake formation on membrane surface, factors affecting permeate flux were investigated experimentally and theoretically. Initial flux decline rate was significantly affected
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by porosity and particle size. As cross-flow velocity determines back transport rate. It gave steady-state flux value. When polidispersity of influent was considered, numerical, calculation showed that smaller particles accumulated in cake layer formed on membrane with time elapsed. It was because shear effect was increased with increase on particle size enchancing back transport.
3) New microfiltration membrane with pore size of 100 nm rejected 90% of E. colt Q_<beta> (ca. 25 nm in size) applied due to adsorption. The cake layer, formed on membrane significantly increased the rejection in natural pond water filtration. Significant leak of Q_<beta> was observed through ultrafiltration membrane (40, 000 dalton of molecular, cut off size). Even though real rejection was high enough, observed rejection might be significantly reduced due to concentration polarization.
4) Based on the above results, preliminary design of of a purification plant (capacity 50, 000 m^3/d) was done adopting hollow fiber module as membrane configuration. It was shown that land area required for the membrane plat was much smaller than that for, a conveational purification plat with same capacity, in case the permeate flux was maintained 0.5 m/d. In case no recycling of feed stream is the system, the operational cost becomes always cheaper than that of the conventional one. Less
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Research Products
(10 results)
