A novel electrocoagulation process using insulated edges of Al electrodes for enhancement of urban wastewater treatment: Techno-economic study

摘要

A comparison between conventional process and novel process of insulated edges electrodes in a batch electrocoagulation (EC) reactor for the treatment of urban wastewater was undertaken to investigate the effect of current density, operating time and initial temperature on the treatment efficiency. The optimal experimental conditions are found to be: current density of 20 mA cm(-2), operating time of 6 min and initial temperature of 45 degrees C for phosphorous (P) and 55 degrees C for chemical oxygen demand (COD). The high removal efficiencies of COD and P using conventional electrodes system were found to be 89% and 99%, respectively. By comparison, the removal efficiencies using insulated edges of electrodes were achieved 91% for COD and 99.5% for P. The adsorption capacities of COD and P for conventional and novel processes were found to be 5930 mg COD kg(-1) and 80 mg P kg(-1), and 5860 mg COD kg(-1) and 77 mg P kg(-1), respectively. The sludge generated at optimum operating conditions using conventional and novel processes were calculated as 1.5 kg m(-3) and 1.8 kg m(-3), respectively. Also, insulated electrode process exhibited the ability to reduce the cost to 0.62 $ kg(-1) for COD and to 0.58 $ kg(-1) for P. The characterization study of produced sludge confirms that metal hydroxides and oxyhydroxides constitute the main components that contributed strongly to remove COD and P from urban wastewater. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.