Modelization and Statistical Optimization of Coagulation-Flocculation Treatment of an Old Leachate

Coagulation/flocculation process was studied using the response surface methodology (RSM) and central composite design (CCD), to design the experiments, develop models, evaluate the relationship between operating factors (FeCl3 dose [m] and pH), and provide an efficient method for the treatment of old leachates. The quadratic polynomial models developed for chemical oxygen demand (COD) and turbidity responses indicated that the optimum conditions were m of 0.82 g/L at pH 5.33 with coefficient of determination R2 of 98.88 and 99.84%, and adjusted R2 of 98.09 and 99.73% for both COD and turbidity. The experimental data and model predictions agreed well. Chemical oxygen demand, turbidity, lead and copper removal efficiency of 76.4, 98.9, 99 and 99%, respectively, were reached.