Continuous electrocoagulation treatment of chromium from tannery wastewater in a cylindrical column

Abstract

Discharging tannery wastewater into the water resources can lead to several environmental implications due to its high chromium and pollutants content, adversely affecting both aquatic and human life. Consequently, researchers are focusing on the development of efficient treatment methods for post-tanning effluents with the target of removing chromium to alleviate this pollution problem. In this regard, electrocoagulation has emerged as a leading technology for chromium removal from tannery wastewater. In this study, a continuous electrocoagulation column was applied for the removal of chromium ions from tannery wastewater collected from local industry. The effect of current density, pH, and effluent chromium concentration were studied for the removal of chromium ions. The results showed that a maximum chromium removal (99.94 %) was achieved within one hour in batch mode at current density, pH, and effluent concentration of 10 mA/cm², 6.5, and 500 mg/L, respectively. The continuous electrocoagulation system was used to evaluate the process dynamics and steady-state stability of the reactor system by introducing step changes in operating conditions (flow rate, pH, current density, and concentration). The experiments of the continuous electrocoagulation reactor system were conducted at a flow rate of 50 ml/min (HRT = 34 min) with the results promise effective removal of chromium ions from tannery wastewater using the electrocoagulation system.