Source water pollution with Cryptosporidium oocysts and removal and inactivation in water purification system

一年的实地考察on Cryposporidium pollution in river water was carried out at 11 stations inSagami river. The level of Cryptosporidium in The river ranged 1-11,000 oocysts/ 100l with geometricmean of 24 oocysts/1OOL and the level of Giardia was in the range of 1-20,000 cysts/lOOL withgeometric mean of 12cysts / 1ool . the levels of oocysts and cysts were significantly correlated withthe levels of at-tolerant Clostridium perfringens spores. Thus，the heat-tolerant Clostridium perfringens spores were recommended as primary indicator for protozoanpollution of waters.Experimental study of the assessment of ozonation and electric disinfectionsystem composed of 8 layers of carbon graphite disks for inactivating Cryptosporidium parvumoocysts是conducted. Ozonation could reduce the infectivity of the oocysts by 2logs at CT productof 3 - 6 mg min/L.Electric disinfection system removed the oocysts by 2-3 logs by passing oncethrough the system. the oocysts trapped on the carbon graphite disc were killed by 40% withinhours and by greater than 8% within 72 hours。

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.