Efficacy of electrocoagulation and electrooxidation for the purification of wastewater generated from gelatin production plant

Abstract

The effluents of gelatin production plant are highly complex and difficult to treat by conventional methods. The electrochemical techniques involving electrocoagulation and electrooxidation were attempted for the treatment of wastewater from gelatin production plant. Around 60% of TOC removal was achieved by electrocoagulation using aluminum as anode. However, the performance was severely affected due to scaling of the electrodes. The high concentration of dissolved calcium was found to be responsible for scaling of electrodes. To minimize the scaling, calcium was precipitated as CaCO3 using bicarbonate. After the calcium was precipitated, scaling was reduced and the performance of the electrodes was drastically improved. The effect of applied current density and flow rate on TOC removal was studied and the energy consumption for electrocoagulation was estimated. Since the removal of pollutants by electrocoagulation is only partial, the wastewater was processed further by electrooxidation using IrO2–Ta2O5 coated Ti electrode and TiO2 nanotubes grown on titanium sheet (TiO2 NT) as electrodes. The TOC removal was drastically improved in the presence of TiO2 NT electrode.