Purification of Heavy Metals Contaminated Groundwater by Electro-coagulation Process Using Graphite Electrodes

Abstract

Background: The subject of this study was the application of the electro-coagulation process to a contaminated groundwater identified in the Abala community, which is a suburb of the Ilorin metropolis in Kwara state, Nigeria. Methods: The electro-coagulation process was applied to the groundwater samples in a 2.5-L batch reactor containing 1 L of the contaminated water. Each run lasted for 1 hour, and a DC power supply was used with a voltage range of 10 to 20 V at a constant current of 5 amp, or 2amp to 6amp at a constant voltage of 10 V. Also, graphite electrodes were employed in the process. Results: The results revealed that the electro-coagulation process could reduce turbidity, total dissolved solids (TDS), electrical conductivity (EC), biological oxygen demand (BOD), total organic carbon (TOC), chemical oxygen demand (COD), and color by 97.3, 91.2, 91.1, 96, 99.7, 99.7%, 79.9%, and 82.96%, respectively. Through an atomic absorption spectroscopy analytical study, the process also showed removal efficiency of manganese (Mn), iron (Fe), and zinc (Zn) of 82.96%, 70.0%, and 95.30%, respectively. The results of the electro-coagulation process met the drinking water and general industrial wastewater discharge guidelines set by the World Health Organization (WHO), the United States Environmental Protection Agency (USEPA), and the Water Environment Partnership in Asia (WEPA). Conclusion: The observations of this study indicated that electro-coagulation is an efficient and effective treatment method for the contaminated groundwater. Therefore, this study recommends the use of electro-coagulation for treating contaminated groundwater in Nigeria.