| Project/Area Number |
09650611
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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 | Setsunan University |
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Principal Investigator |
KANEKO Mitsumi Setsunan University, Department of Engineering Professor, 工学部, 教授 (50083738)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1998: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1997: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Keywords | Ozone / Cryptosporidium parvu / Oocyst / Ct value / disinfection / クリプトスポリジウム / オゾン消毒 / 脱嚢試験 / ct値 / DAPI / PI染色試験 |
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| Research Abstract |
Waterbone outbreaks caused by the oocysts of Cryptosporidium which are resistant to many water treatment processes are increasingly reported. In order to examine the potential of ozone for activating Cryptosporidium parvum were conducted.
The evaluation of disinfection wais distinctively affected by the method of judge merit of vitality of oocysts. The most reliable estimation on the survival number of of infective oocysts should be obtained by the method depended on infective activity of oocysts using living animals. The Ct values for 90%(llog) and 99%(21og90%) reduction of oocysts examined by the method of excystation were 7-8mg・min/iotaand l2mg・min/iotaA.respectively. The Ct values for oocyst inactivation judged by DAPI/PI staining method were 7-llmgmin/iota. and 20 mg・min/iota for the reductions of 90%(llog) and 99%(2log) respectively . When the Ct value of ozone was estimated using the results obtained by infectivity of oocysts to mice, the Ct value for 99%(2log) reduction was 6 mg・min/iota. The Ct value of chlorine estimated by infevtive activity was 1200 mg・minIL for 9O%(1log) reduction , indicating that the Ct value of chlorination was lessthan the values reported so far. However this value is not not enough to guarantee the safety of water quality against Cryptosporidium. It is concluded from this study that ozone can be used to obtain the safe water against Cryptosporidium taking the Ct value of around 10 mg・min/iota.
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