Optimization of electrocoagulation process to treat biologically pretreated bagasse effluent

The main objective of the present study was to investigate the efficiency of the electrocoagulation process as a post-treatment to treat biologically pretreated bagasse effluent using iron electrodes. The removal of the chemical oxygen demand (COD) and the total suspended solids (TSS) were studied under different operating conditions, such as amount of dilution, initial pH, applied current and electrolyte dose using the response surface methodology (RSM) coupled with a four-factor three-level Box-Behnken experimental design (BBD). The experimental results were analyzed by the Pareto analysis of variance (ANOVA) and second order polynomial mathematical models were developed with high correlation of efficiency (R-2) for COD, TSS removal and electrical energy consumption (EEC). The individual and combined effects of the variables on the responses were studied using three dimensional response surface plots. Under the optimum operating conditions, i.e., amount of dilution at 30 %, initial pH of 6.5, applied current of 8 mA cm(-2) and electrolyte dose of 740 mg L-1, high removal efficiencies of COD (98 %) and TSS (93 %) were obtained with an EEC of 2.40 Wh, which were confirmed by validation experiments.