Hazards of Cryptosporidum and Giardia and Its Control Technology

A major public health problem is water pollution of pathogenic microorganism and the pathogenic microorganism presence in drinking water.Cryptosporidium and Giardia are considered as main waterborne protozoan parasites causing human diarrhea,posing a serious threat to drinking water safety.Cryptosporidium oocysts and Giardia cysts have a strong resistance and volume of low infective dose.Conventional chlorine disinfectant cannot effectively inactivate Cryptosporidium and Giardia.Among physical methods to remove or inactivate Cryptosporidium and Giardia,reverse osmosis,membrane filtration and freeze-thaw methods with high cost,are not suitable for large scale water treatment.UV method can more effectively inactivate Cryptosporidium and Giardia,but limit the inactivated effect of Cryptosporidium and Giardia in deeper because of weak UV penetration.Among chemical methods,ozone oxidation has the best effect on inactivation of Cryptosporidium and Giardia.Variety of disinfectants used in combination by synergy could reach a higher inactivation rate.