Treatment of domestic sewage using electrocoagulation followed by ion exchange – parametric and kinetic studies

Abstract

Viable and low treatment cost is a challenge for municipal wastewater, therefore, an efficient and cost-effective electrocoagulation (EC) process was studied to treat domestic sewage (DS) in laboratory batch process using SS-304 as electrode material. Effects of various parameters such as pH, current, electrode configuration in numbers and treatment time (tR ) were tested to find optimum operating condition for COD and other pollutants removal. The optimum 78.47% COD reduction of initial COD = 288 mg/dm3 was obtained at pH = 8, number of plates = 6, current density (CD) = 27.78 A/m2 (2A) and tR = 20 min. At this operating condition, the treatment cost in terms of electrode loss and energy consumption was evaluated to be 187.54 Rs/m2. The kinetic parameters such as rate constant, reactant (COD) order and current density (CD) order were also evaluated by using experimental data fitted to MATLAB solver. The order with respect to COD was found to be 1.4 and with respect to CD 0.64. The EC-treated DS was further treated by ion exchange process to reduce hardness, COD and total dissolved solid. The two-stage treatment reduced water pollutant to significant level and could be used for irrigation and other household purpose.