Municipal effluents treatment using chlorine dioxide and chlorine

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.