Inactivation of Giardia intestinalis by H_2O_2/O_3

摘要

The objective of this study was to investigate the effect of H_2O_2/O_3 inactivating Giardia intestinali (G. intestinali) by the fluorescence staining method and vitro excystation. Results suggested that hydroxyl radicals (·OH) was the principal factor during the H_2O_2/O_3 process by testing the effect of t-butyl alcohol (TBA) and concentration change of H_2O_2. The inactivation rate achieved 99.6% when independent addition of O_3 under 1.5 mg·L~(-1) with contact time about 10.0 min. While to achieve the same inactivation effect by H_2O_2/O_3, 1.0 mg·L~(-1) O_3 ([H_2O_2]/[O_3] molar ratio = 0.8) with 7.0 min was required. The inactivating capability was stronger under acidic condition than in alkaline environment. The effect of turbidity was also found to be significant in synthetic water, when turbidity increasing, the inactivating effect declined. Inactivation rate was improved with a temperature increase from 5 to 35°C. When dissolved organic matter concentration in the reaction system increased, the competitive reaction between G. intestinal and organics with H_2O_2/O_3 probably took place, thereby reducing the inactivation rate.