EFFECTS OF OZONATION AND CHLORINATION ON VIABILITY AND INFECTIVITY OF CRYPTOSPORIDIUM PARVUM OOCYSTS = 크립토스포리디움 原蟲의 不活性에 대한 오존과 監素의 效果

다국어 초록 (Multilingual Abstract)

ABSTRACT
Experimental studies on ozonation and chlorination were conducted to determine capacity for inactivating Cryptosporidium parvum oocysts in batch modes at pH 7, 20℃. In both experiments, the log reduction of animal infectivity was linear and clearly decreased as disinfectant CT product increased. However, the curve of reduction in viability determined by both in vitro excystation assay and DAPI/PI permeability assay exhibited a shoulder. The CT products of ozone per 1 log reduction in infectivity were 3 mg·min/L for 0.5 mg/L and 1.5mg·min/L for 0.3 mg/L, while viability determined by in vitro excystation was reduced by only 0.2 logs for the CT product of 3 mg·min/L. In the chlorination experiment, the reduction of animal infectiviry was up to 3 logs for the CT product of 2,700 mg·min/L, while reduction of viability was smaller at 0.16 logs in in vitro excystation and 0.04 logs in DAPI/PI permeability (in PI exclusion)for the same CT product. The CT product of free chlorine per 1 log
reduction in infectivity was estimated to be in the range of 800 to 900 mg·min/L

다국어 초록 (Multilingual Abstract)

Experimental studies on ozonation and chlorination were conducted to determine capacity for inactivating Cryptosporidium parvum oocysts in batch modes at pH 7, 20℃. In both experiments, the log reduction of animal infectivity was linear and clearly decreased as disinfectant CT product increased. However, the curve of reduction in viability determined by both in vitro excystation assay and DAPI/PI permeability assay exhibited a shoulder. The CT products of ozone per 1 log reduction in infectivity were 3 mg·min/L for 0.5 mg/L and 1.5 mg·min/L for 0.3 mg/L, while viability determined by in vitro excystation was reduced by only 0.2 logs far the CT product of 3 mg·min/L. In the chlorination experiment, the reduction of animal infectivity was up to 3 logs for the CT product of 2,700 mg·min/L, while reduction of viability was smaller at 0.16 logs in in vitro excystation and 0.04 logs in DAPI/PI permeability (in PI exclusion) far the same CT product. The CT product of free chlorine per 1 log reduction in infectivity was estimated to be in the range of 800 to 900 mg·min/L.

목차 (Table of Contents)

• INTRODUCTION
• MATERIALS AND METHODS
• RESULTS AND DISCUSSION
• Effect of Ozonation
• Effect of Chlorination
• Effect of Applied Chlorine Concentration on CT Requirement
• Expected Reduction in Infectivity by Current Disinfection Practice
• Appropriate Method for Evaluating the Effect of Disinfectants
• CONCLUSIONS
• AKNOWLEDGEMENT