Removal of Chromium by Electrocoagulation Process from Tannery Industry Wastewater in Cusco, Peru

Removal of chromium from tannery wastewater was studied using the electrocoagulation process at laboratory level, aluminum and steel electrodes was employed to remove chromium ions during electrocoagulation process. Tannery wastewater were collected from industries located in Sicuani, Cusco, Peru. Considering an initial concentration of chromium of 237 ppm, and pH of 3.75. First, the removal efficiency of chromium was tested by electrocoagulation process from synthetic solutions using three level factorial design of experiments, in this case two variables were assessed: current density (3.09, 6.17, and 9.26 mA/cm2), and pH (6, 7, and 8). A statistical analysis was employed to these factors in order to find better conditions of electrocoagulation operation. The most influent factor was the pH, follow by current density, and in less proportion their interaction. The best conditions for removing chromium were at 9.26 mA/cm2, and pH of 8, reaching 99.99% of removal. All experiments were tested at fixed 35 minutes of treatment. Then, a kinetic study was developed, where experimental data were fitted better to first order reaction, reaching equilibrium at 15 minutes. Finally, tannery industry wastewater was treated by electrocoagulation, where a removal efficiency of 98.6% was achieved.