OPTIMIZING REMOVAL OF HEAVY METALS IN INDUSTRIAL WASTEWATER BY IMPLEMENTING ELECTROCOAGULATION TECHNIQUE USING ALUMINIUM ELECTROD

Abstract

A suitable technology is required to develop an intensive method to be applied in many industries which was increasingly in demand. Recently, there are several studies that proved electrocoagulation as the most promising technique. A laboratory scale electrocoagulation process with a rectangular Plexiglas can effect at various operating parameters. The objectives of this study are to examine the effect of the operating parameters; to determine the effect of initial pH for removal heavy metal, COD, and turbidity using both aluminium and iron plate electrodes, inter-electrode spacing of metal plates on removal copper, nickel, zinc, and chromium, and lastly to investigate the suitable treatment time for removal COD and turbidity Initial pH was adjusted to 2, 4, 6, 8, and 10, while inter-electrode spacing varies with 1.5, 2.5, 3.5, and 4.5cm with a constant current density, 0.5A/m2. Operating time for each pollutant studies are evaluated every 20 minutes for an hour. From the studies, Ni, Cu, and Zn are faster removed than hexavalent chromium using aluminium electrode instead of iron electrode, which is up to 80%. Turbidity and COD present are also removed, more than 50% and up to 90%. From the result achieved, it is strongly agreed that the best removal capacity for all studied metals achieved in the pH range from 4 to 8. The results show that, the percent removal efficiency of Cu, Cr, Ni, Zn, COD, and turbidity are increased by increasing the initial solution pH and increasing the operating time. The results showed that 90% of the pollutants- can be removed within 60 minutes. It is highly recommended to practice this technique in pilot plant to observe whether the technique can be applied economically in industrial as well as to analyze the cost effectiveness by investigating and compared with other treatment methods. Based on the results, industrial wastewater quality is compared according to the standard that stated in the Environmental Quality Act (Sewage and Industrial Effluents) Regulations 1979, Maximum Effluent Parameter Limit Standard A