Efficiency of coagulation-flocculation and chlorination processes in the removal of endosulfan from water sources

Abstract

In this study, the efficiency of conventional drinking water treatment processes (coagulation-flocculation and chlorination) for endosulfan removal and metabolite formation were investigated. Taguchi experimental design and analysis of variance (ANOVA) were applied using Minitab program. The highest removal efficiency was obtained as 65% at 6 mg/L initial endosulfan concentration, 30 mg/L aluminium sulfate dose and pH 7, in the coagulation-flocculation experiments. In chlorination experiments, it was determined that the variables of initial endosulfan concentration, chlorine dose, pH and contact time contributed 55.84%, 21.25%, 5.74% and 3.48% to the endosulfan removal, respectively, according to the ANOVA results. The presence of endosulfan metabolites like endosulfan ether, sulfate, and lactone were also detected and measured. P values were obtained only in endosulfan sulfate formation as a result of chlorination, lower than 0.05 for initial endosulfan concentration, chlorine dose and time parameters; apart from this, P values were not statistically significant in all other experiments.