Assessing the effect of operating factors on phosphate removal by electrocoagulation process using Response Surface Methodology

Abstract

This study investigated the electrocoagulation batch model with two aluminum plate electrodes. The effect of operating factors on phosphate removal efficiency by electrocoagulation process using aluminum electrodes was evaluated by Response Surface Methodology (RSM), including current density, pH, initial phosphate concentration, and reaction time. A total of 15 experiments were set up following the Box-Behnken method in Design – Expert 12 software, with three center points. The optimal operating conditions were determined by analyzed collected data in Design – Expert 12 software: current density of 16.7 A/m2, pH 5.6, reaction time of 33.5 min, and initial phosphate (P-PO43-) of 66.249 mg/L. The correlation equation between treatment efficiency and factors was also determined as a quadratic model with R2 = 0.9771. The interaction between the pairs of factors significantly affected P-PO43- treatment efficiency, represented by 3D surface plots. The maximum P-PO43- treatment performance was reached 99.6%. The treatment efficiency of real livestock wastewater was determined and reached a high agreement with the predicted value, 99.7% after 30 min. Generated sludge was evaluated, approximately 6.3±0.76 kg per 1 m3 treated wastewater.