The investigation of endosulfan removal in conventional drinking water treatment processes

In this thesis study, endosulfan removal and metabolite formation by conventional drinking water treatment methods were examined. In the study, coagulation-flocculation and disinfection processes as conventional treatment methods were performed using aluminum sulfate and sodium hypochlorite. In addition, Taguchi experimental design and ANOVA analysis were used using the Minitab program. In coagulation-flocculation experiments, 3 parameters, 4 levels were selected and analyzes were performed with only 16 experiments using Taguchi method; thereby both a small number of experiments were performed and the factors and levels that affect the removal were determined. In disinfection experiments, 4 parameters, 4 levels were selected and the results of the analysis were reached in a short time with 16 experiments. In the coagulation-flocculation study, the best removal efficiency with 65% was achieved at initial endosulfan concentration 6 mg/L, aluminum sulfate dose 30 mg/L and pH 7. On the other hand, the most effective parameter levels were found at initial endosulfan concentration 6 mg/L, aluminum sulfate dose 40 mg/L and pH 8 in the analyzes obtained by Taguchi method. From the ANOVA results, the pH was 58.16%; the initial concentration of endosulfan was 32.50%; and aluminum sulfate dose was 1.34%. The reliability of the model is 92% and is quite high. In disinfection experiments, the initial endosulfan concentration was 6 mg/L, chlorine dose 5 mg/L, pH 5, while the best endosulfan removal was 33% for 45 minutes. In disinfection experiments, the initial endosulfan concentration was 6 mg/L, chlorine dose 5 mg/L, pH 5, while the best endosulfan removal was 33% for 45 minutes. In the analysis conducted by Taguchi method, the best parameter levels were determined for the initial concentration of endosulfan 6 mg/l, chlorine dose 5 mg/l, pH 5, and contact time 30 minutes. Initial endosulfan concentration, chlorine dose, pH and contact time were determined from the ANOVA results, respectively 55.84%; 21.25%; 5.74% and 3.48% contributions to the model. The reliability of the model is 86.31% and is quite high. Endosulfan ether, endosulfan sulfate and endosulfan lactone formation during endosulfan removal were also evaluated by ANOVA analyzes.