Inactivation of Chironomid larvae with chlorine dioxide.

In this paper, comparative experiments on the inactivation of Chironomid larvae by chlorine dioxide and chlorine were conducted. In addition, batch experiments were performed in order to analyze the influence of pH value, organic precursor concentration and temperature on the inactivation efficiency of Chironomid larvae with chlorine dioxide. Based on it, removal effect of different pre-oxidation followed by coagulation process on Chironomid larvae in raw water was evaluated. The results showed that chlorine dioxide possessed better inactivation performance than chlorine, and complete inactivation of Chironomid larvae was obtained at CT value of 37.5 mg min/L (dose of 1.5mg/L and exposure time of 25 min). The pH in the range of 6-8 did not affect the inactivation efficiency of chlorine dioxide, whereas pH 10 resulted in around 10% decrease in inactivation rate. Meanwhile, the organic precursor had negative effects on inactivation, indicated by the decreased inactivation rate from 100% at TOC concentration of 0mg/L to 62.2% at 8 mg/L when the CT value was 45 mg min/L. With regard to the temperature, the inactivation efficiency of Chironomid larvae was significantly improved with the temperature increasing within the range investigated of 10-25 degrees C. The inactivation rate was reduced by 68.9% when temperature reduced from 25 degrees C to 10 degrees C. The coagulation jar test showed that Chironomid larvae in the raw water could be completely removed by chlorine dioxide pre-oxidation in combination with the coagulation process at CT value of 24.8 mg min/L.

[1]  H. Junli,et al.  Disinfection effect of chlorine dioxide on viruses, algae and animal planktons in water , 1997 .

[2]  G. Bakker,et al.  Sampling and quantifying invertebrates from drinking water distribution mains. , 2004, Water research.

[3]  J. Nawrocki,et al.  Biodegradability of organic by-products after natural organic matter oxidation with ClO2--case study. , 2004, Water research.

[4]  J. Hoigné,et al.  Kinetics of reactions of chlorine dioxide (OClO) in water—I. Rate constants for inorganic and organic compounds , 1994 .

[5]  An attempt to trace eutrophication in a shallow lake (Balaton, Hungary) using chironomids , 1983 .

[6]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[7]  B. Mariñas,et al.  Sequential inactivation of Cryptosporidium parvum oocysts with chlorine dioxide followed by free chlorine or monochloramine. , 2002, Water research.

[8]  R. Andrew,et al.  Development of chlorine dioxide-related by-product models for drinking water treatment. , 2002, Water research.

[9]  Robert C. Andrews,et al.  RETRACTED: Disinfection of Bacillus subtilis spores with chlorine dioxide: a bench-scale and pilot-scale study , 2002 .

[10]  F. Chao,et al.  Mechanisms of inactivation of hepatitis A virus in water by chlorine dioxide. , 2004, Water research.

[11]  S. Charles,et al.  Food availability effect on population dynamics of the midge Chironomus riparius: a Leslie modeling approach , 2004 .

[12]  Gordon R. Finch,et al.  Sequential disinfection of cryptosporidium parvum by ozone and chlorine dioxide , 1997 .

[13]  Benito Jose Marinas,et al.  Inactivation of Cryptosporidium parvum oocysts with chlorine dioxide , 2000 .

[14]  N. Ren,et al.  Disinfection effect of chlorine dioxide on bacteria in water , 1997 .