Municipal effluents treatment using chlorine dioxide and chlorine

Abstract

The using of combined process consisting of chlorine dioxide and chlorine, for the treatment of municipal effluents in order to search their advanced oxidation and disinfection possibilities, was investigated in this paper. The following sets of oxidant concentrations were used, 15.0 mg/L ClO2 + 5.5 mg/L Cl2 (1); 10.0 mg/ L ClO 2 + 3.6 mg/L Cl2 (2); 7.5 mg/L ClO2 + 3.0 mg/L Cl2 (3), for the treatment of some effluent samples from wastewater treatment plant of Timisoara. Organic content of samples expressed as chemical oxygen demand, decreased due to oxidation process with 17.8 - 20.7 % during 24 h, when first set of concentrations was used (1). The efficiency of disinfection for the removal of total coliforms, fecal coliforms and fecal streptococci ranged between 90.0 – 99.9 % , at 2 h after reagents introduction in effluent samples, and were realized with 7.0 mg/L chlorine dioxide and 3.0 mg/L chlorine. By using of combined reagents, both advanced oxidation and disinfection of wastewater take place, allowing their safe discharge into environment.