Inactivation and Influnencing Factors of Oxidants on the Fourth Instar Larvae of Chironomus Kiiensis in Drinking Water

Chironomus kiiensis larvae which cannot be exterminated by conventional disinfection process propagates prolifically in eutrophic water body, and it therefore turns to be a potential problem encountered in drinking water quality. In this paper, comparative experiments on the inactivation of the fourth instar larvae of Chironomus kiiensis in distilled water by chlorine, ozone and chlorine were conducted. In addition, batch experiments were performed in order to analyze the influence of pH, organic precursor concentration and algae concentration on the inactivation efficiency of the fourth instar larvae of Chironomus kiiensis with ozone and chlorine dioxide. The results showed that ozone possessed better inactivation effect on the fourth instar larvae of Chironomus kiiensis in distilled water compared with chlorine dioxide and chlorine. However, organic precursor and algae concentration significantly affected inactivation of the fourth instar larvae of Chironomus kiiensis with ozone. The inactivation rate rapidly declined as organic precursor and algae concentration increased. Meanwhile, pH in the range of 4-7 did not affect the inactivation rate of ozone, whereas the inactivation rate was reduced by 46.7% when pH increased from 7 to 10.