Separation Science and Technology, Vol.53, No.10, 1592-1603, 2018
Container washing wastewater treatment by combined electrocoagulation-electrooxidation
Treatment of container washing wastewater (CWW) by using combined electrocoagulation (EC)-electrooxidation (EO) process was studied. CWW contains many organic compounds such as surfactants used in cleaning agents. Wastewater was first treated by EC with iron (Fe) and aluminum (Al) electrodes. The process performance was measured according to the removal efficiencies of soluble chemical oxygen demand (sCOD) and color. Maximum sCOD removal efficiency was found 82% and color removal efficiencies were 95%, 95% and 98% at 436, 525 and 620nm, respectively, with Fe electrodes under 25mA/cm(2) current density, initial pH of 5 and 120-min operation time. Because of the low sCOD removal efficiency, EO was used as post-treatment process by using boron doped diamond electrode (BDD). sCOD removal efficiency was increased to 89% and color removal efficiencies decreased to 72%, 64%, 71% at 436, 525 and 620nm, respectively, under 25mA/cm(2) current density, initial pH of 3 and 300-min operation time. This study showed that electrochemical processes caused new complex molecules formation in the CWW, which caused deterioration of water color and limited the process efficiency.