Modeling and Optimization of COD Removal from Leachate by Electrocoagulation: Application of Central Composite Design

Abstract

The present study aims to investigate the treatment of leachate by the electrocoagulation (EC) process using aluminum electrodes. A response surface methodology (RSM)-based central composite design (CCD) was carried out to design the experiments, develop a statistical model, assess the relationship between the four variables, and predict the responses, namely, the chemical oxygen demand (COD). The removal efficiency of COD, biological organic matter (BOD5), and turbidity were about 90%, 92.3%, and 99.6%, respectively, under optimum operational conditions, i.e., initial pH (5.3), current intensity (1.2 A), electrolysis time (75 min), and stirring speed (150 rpm). The operating cost of the current EC treatment was 0.6 €/m3. Moreover, the coefficient of determination (R2) revealed a satisfactory agreement between observed and expected results. Therefore, RSM is an appropriate approach to determine the key parameters for electrocoagulation process.