Document Type : Research Paper


1 Chemical Engineering Department,College of Engineering, University of Al-Qadisiyah, Iraq

2 Department of Biochemical Engineering, Al-Khwarizmi College of Engineering, University of Baghdad, Baghdad, Iraq


The present study focused on the treatment of hospital wastewater generated from Al-Diwaniya Hospital located at Al-Diwaniya City/ southern Iraq via an Electrocoagulation (EC) process with SS/Fe electrodes. Response Surface Methodology (RSM)  was used to evaluate the main effects of parameters, their simultaneous interactions, and the quadratic effect to achieve the optimum condition for the EC process. Chemical Oxygen Demand (COD) was observed and measured for each experiment as it can be used as a good indicator of the quality of wastewater. The impacts of three factors such as current density (5-25mA/cm2), pH (4-10), and addition of NaCl(0-3g/l) were evaluated. The obtained experimental data were fitted to a second-order polynomial equation with analysis by variance analysis (ANOVA).  The results show that current density has a major impact on the efficiency of COD removal followed by the addition of NaCl while pH has a lower effect on the COD removal under the studied range of pH. ANOVA results showed that the determination coefficient of the models was R2 98.18% confirming that the quadratic model was significant with a good fitting between the experimental and predicted results.  The optimized operating parameters were a current density of 25 mA/cm2, pH of 7.8, and NaCl addition of 3 g/l in which COD removal efficiency of 97.14% was achieved with a specific energy consumption of (30.914) kWh/kgCOD.