Experimental Study on Inactivation of Copepod with Current Available Oxidants

The inactivation of Copepod with available oxidants such as chlorine, chlorine dioxide, ozone and potassium permanganate were investigated under various working conditions of different oxidant dosage, organic substance content and pH value. The results showed that chlorine dioxide might be most effective to inactivate Copepod than other oxidants and complete inactivation effect may be attained by 1.0 mg/L of chlorine dioxide, on which extraneous factors such as organic matter content and pH value had little influence. But for chlorine and ozone, the required dosage of complete inactivation was 2.0 mg/L. Only 60% of Copepod was inactivated by 2.0 mg/L of potassium permanganate contacting for 30 min. The influence of pH value on inactivation rate of chlorine and potassium permanganate were more sensitive than that of chlorine dioxide and ozone. The influence of organic substance on ozone was the most visible and the experimental results indicated the decreased inactivation rate from 100% at TOC concentration of 0 mg/L to 10% at 8 mg/L. The removal effect on Copepod by chlorine dioxide preoxidation cooperating with conventional clarification process was investigated in full scale experiment. Complete removal was attained by 0.8 mg/L of chlorine dioxide preoxidation cooperating with subsequent clarification.