Optimization of Coagulation Process for Disperse Navy Blue Dye Wastewater Treatment Using Response Surface Methodology

A response surface methodology (RSM) was used for the determination of optimum coagulation process conditions for disperse navy blue dye wastewater treatment. The experimental design was Box-Behnken design (BBD) with three operational variables: coagulant dosage, pH value and settling time. The influence of these three independent variables on the chroma removal was evaluated using a second-order polynomial multiple regression model. Quadratic model was predicted for the response variable and the maximum model-predicted chroma removal efficiency was 95%. Based on surface and contour plots, the optimum conditions were obtained to be coagulant dosage of 70.98 mg/L, pH value of 7.46, and settling time of 15.80 min with the actual chroma removal efficiency as 93%.