| Project/Area Number |
09650606
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Civil and environmental engineering
|
|---|
| Research Institution | College of Environmental Health, Azabu University |
|---|
Principal Investigator |
HIRATA Tsuyoshi Azabu University, College of Environmental Health, Professor, 環境保健学部, 教授 (50005493)
|
|---|
| Project Period (FY) |
1997 – 1998
|
| Project Status |
Completed (Fiscal Year 1998)
|
| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1998: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1997: ¥1,700,000 (Direct Cost: ¥1,700,000)
|
|---|
| Keywords | Cryptosporidium / Giardia / Protozoan pollution / ozonation / electric disinfection / inactivation / 嫌気性芽胞 / 好気性芽胞 / 大腸菌 / ウェルシュ菌芽胞 / 水環境汚染 / 浄水処理 / 感染リスク |
|---|
| Research Abstract |
One-year field survey on Cryposporidium pollution in river water was carried out at 11 stations in Sagami river. The level of Cryptosporidium in the river ranged 1-11,000 oocysts/100L with geometric mean of 24 oocysts/1OOL and the level of Giardia was in the range of 1-20,000 cysts/lOOL with geometric mean of 12 cysts/1OOL.The levels of oocysts and cysts were significantly correlated with the levels of heat-tolerant Clostridium perfringens spores. Thus, the heat-tolerant Clostridium perfringens spores were recommended as primary indicator for protozoan pollution of waters.
Experimental study of the assessment of ozonation and electric disinfection system composed of eight layers of carbon graphite disks for inactivating Cryptosporidium parvum oocysts was conducted. Ozonation could reduce the infectivity of the oocysts by 2 logs at CT product of 3 - 6 mg・min/L.Electric disinfection system removed the oocysts by 2-3 logs by passing once through the system. The oocysts trapped on the carbon graphite disc were killed by 40% within 24 hours and by greater than 8O% within 72 hours.
|
