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Inactivation of Cryptosporidium parvum oocysts by sequential disinfection with chlorine following ozone

臭氧后用氯连续消毒灭活小隐孢子虫卵囊

基本信息

批准号：
11650566
负责人：
HIRATA Tsuyoshi
金额：
$ 2.3万
依托单位：
Azabu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650566/
关键词：
Cryptosporidium parvum Oocysts Ozone Chlorine Sequential Disinfection Excystation Mouse Infectivity マウス感染性

项目摘要

The effects of free chlorine and ozone on infectivity of Cryptosporidium parvum oocysts were evaluated. Free chlorine CT (the product of concentration and contact time) requirement for reduction in infectivity was highly dependent on exposed chlorine concentration at the range of 1 to 100 mg/L.Obtained relationship between CT values for n log reduction in infectivity (CTn mg min/L) and exposed mean free chlorine concentration (C mg/L) was CTn = n・(21.3C+793) at 20 C, pH 7.0. As for ozone, CT requirement did not show any dependency on ozone concentration at the tested range of 0.1 to 1.0 mg/L and obtained ozone CT values for 2 log reduction in infectivity were in narrow range of 2 to 3 mg min/L.The efficacy of combined disinfection with ozone and chlorine was tested. Oocysts were exposed to ozone with the CT of 0.75, 2.0 and 3.0 mg min/L and then exposed to free chlorine of 1,400 mg min/L.Achieved reductions in infectivity by combined disinfection with chlorine following ozone were 2.17, 1.68, 1.43 log for 0.75, 2.0, 3.0 mg min/L of ozone, respectively. As reduction in infectivity by chlorine of 1,400 mg min/L was 1.74 log, excess reductions by combined disinfection were as small as 0.97 log, -0.06 log, -0.31 log for 0.75, 2.0, 3.0 mg min/L, respectively. Thus, synergistic increase in reduction in infectivity was observed in case of 0.75 mg min/L of ozone, but additional reduction by synergistic effect was limited only 1 log. In addition, any significant synergistic effect was not observed in other two cases. From these results, combined disinfection by sequential mode of chlorination following ozonation is not a practical method for expecting excess reduction in infectivity of oocysts by synergistic effect.

研究了游离氯和臭氧对微小隐孢子虫卵囊感染性的影响。在1至100 mg/L范围内，降低感染性所需的游离氯CT（浓度和接触时间的乘积）高度依赖于暴露的氯浓度。在20 C，pH 7.0下，获得的感染性降低的n log CT值（CTn mg min/L）和暴露的平均游离氯浓度（C mg/L）之间的关系为CTn = n·（21.3C+793）。至于臭氧，CT要求没有显示出任何依赖于臭氧浓度在0.1至1.0毫克/升的测试范围内，并获得臭氧CT值为2对数减少感染性在2至3毫克分钟/升的窄范围内。将卵囊暴露于CT为0.75，2.0和3.0 mg min/L的臭氧中，然后暴露于1,400 mg min/L的游离氯中。臭氧后用氯联合消毒的感染性分别为0.75，2.0，3.0 mg min/L臭氧的2.17，1.68，1.43 log。由于1,400 mg min/L氯的感染性降低为1.74 log，因此，对于0.75、2.0、3.0 mg min/L，联合消毒的过量降低分别小至0.97 log、-0.06 log、-0.31 log。因此，在0.75 mg min/L臭氧的情况下观察到感染性降低的协同增加，但通过协同效应的额外降低仅限于1 log。此外，在其他两种情况下未观察到任何显著的协同效应。从这些结果来看，通过臭氧化之后的氯化的顺序模式的组合消毒不是期望通过协同效应过度降低卵囊感染性的实用方法。

项目成果

期刊论文数量（15）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

大垣眞一郎,大瀧雅寛,平田強,片山浩之,小熊久美子: "UV照射および光触媒反応によるクリプトスポリジウムと大腸菌の不活化"東京大学工学部総合試験所年報. 58巻. 65-70 (2000)

Shinichiro Ogaki、Masahiro Otaki、Tsuyoshi Hirata、Hiroyuki Katayama、Kumiko Oguma：“通过紫外线照射和光催化反应灭活隐孢子虫和大肠杆菌”东京大学工程学院综合实验室年度报告第 58 卷。 65-70 (2000)

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通讯作者：

Hirata T,Chikuma D,Shimura A,Hashimoto A,Motoyama N,Takahashi K,Moniwa T. Kaneko M.Saito S and Maede S: "Effects of ozonation and chlorination on viability and infectivity of Cryptoporidium parvum oocysts"Water Science and Technology. 41巻,7号. 39-46 (2000)

Hirata T、Chikuma D、Shimura A、Hashimoto A、Motoyama N、Takahashi K、Moniwa T. Kaneko M. Saito S 和 Maede S：“臭氧化和氯化对隐孢子虫卵囊活力和感染性的影响”水科学与技术。第 41 卷第 7 期。39-46 (2000)