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| In this paper, the inactivation effects of chlorine and chlorine dioxide on Chironomid larvae were investigated and some boundary values in practice were determined under conditions of various oxidant dosage, organic precursor concentration and pH value. In addition, pilot-scale experiments of preoxidation cooperating with routine water clarification process for removal of Chironomid larvae was conducted at the Shenzhen Waterworks in Guangdong Prov., China. It was founded that chlorine dioxide possessed better inactivation effect than chlorine. Complete inactivation of Chironomid larvae in raw water was resulted by ClO2 dose of 1.5 mg l-1 with contact time of 30 min. Additionally, the organic precursor concentration, pH value had little influence on the inactivation effect. At pilot-scale, 78% and 92% of removal efficiency may be attained by sedimentation and filtration process respectively under no oxidant dosing condition. Chironomid larvae can be completely removed from water body by chlorine dioxide preoxidation cooperating with conventional clarification process with 0.51mg l-1 of ClO2, whereas 3.97mg l-1 was required for chlorine. |
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| Keywords:Chironomid larvae; water treatment; chlorine dioxide; inactivation; preoxidation |
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