Electrocoagulation treatment of industrial tannery wastewater employing a modified rotating cylinder electrode reactor

Abstract

The removal of highly concentrated pollutants, presented in a wastewater mixture from industrial tannery effluents by electrocoagulation, was examined. All experiments were carried out in a rotating cylinder electrode reactor with six aluminum anodes and two sedimentation tanks. The influence of the applied current density and rotational speed on the removal efficiency of an electrocoagulation reactor was studied. Chemical oxygen demand was diminished at 70%, while total suspended solids, chromium (III) and turbidity were almost eliminated (>90%) with 6 mA cm−2 of the applied current density. Additionally, a homogeneous cathodic deposit was obtained at the end of each test. Those cathodic deposits and flocs were analyzed by SEM-EDS. Calculations of the cell energy consumption and the produced aluminum cost were estimated for 6 mA cm−2 and 100 rpm, obtaining 1.98 kWh m−3 and $0.7 USD m−3, respectively.