Treatment of Tannery Wastewater by Electrocoagulation using Aluminium and Iron Electrodes

Abstract

This Tannery industry is one of oldest industry the effluent is highly complex and characterized by high Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), suspended solids, dissolved solids, total solids, and color. Untreated Tannery wastewater when discharged directly into the water bodies or into open lands cause irreversible damage to environment. Electrocoagulation is one of the most important electrochemical treatment employed for industrial wastewater treatment to treat highly polluted industrial effluents which have high suspended and colloidal materials, BOD, COD in wastewater. Electrocoagulation treatment is used in this study to study the removal efficiency of BOD, COD, Chromium (Cr) Total Dissolved Solids (TDS) and the effect of pH of tannery wastewater. The experiments were conducted using aluminum and iron as plane and punched electrodes. When aluminum Plane and punched electrodes were used the optimum removal efficiency for plain electrodes was found to be BOD-89.66%, COD-96.21%, Cr-96.05% and TDS-95.77% for punched electrodes BOD-90.86%, COD-98.62%, Cr-96.94% and TDS96.92% and for iron plane electrodes BOD-87.57%, COD94.77%, Cr-93.42% and TDS-93.08% for iron punched electrodes BOD-89.01%, 96.59%, Cr-94.66% and TDS-95.0% at pH of 9, Voltage 20V, for electrode distance of 1cm and 90 minutes electrolysis duration. The Electrocoagulation treatment has proved to be economical and efficient method for the treatment of tannery wastewater rather than chemical coagulation.