Removal efficacy of toxic metals in leachate through micro-organisms isolated from the natural environment

Abstract

Landfill leachate is a serious contaminant for groundwater and surface water because of its potentially toxic metal content. In many countries, leachate is discharged into the natural environment without treatment because of the high disposal cost. However, this environmental problem can be solved by microorganisms, as they can adsorb the contaminants or convert them into end products, and this is cost-effective. This study focused on determining bacteria capable of efficiently removing toxic metals from leachates. Therefore, bacteria were isolated from nature that have a high adsorption and resistance capacity to a number of toxic metals. This potential was achieved by Enterobacter hormaechei, Priestia aryabhattai, and Mycobacterium sacrum, among others. Their efficiency in removing toxic metals compared to raw leachate was Cd (78%, 67%, 78%), Ni (64%, 57%, 56%), Pb (99%, 75%, 76%), Cr (41%, 46%,19%), Co (45%, 60%, 40%), and Cu (80%, 80%, 60%), respectively. According to the results, these bacterial strains proved to be very effective in the treatment of toxic metals from leachate. Therefore, they are good candidates for the treatment of wastewater by bioremedial methods.