POTENTIALS OF BACTERIAL ISOLATES IN BIOREMEDIATION OF PETROLEUM REFINERY WASTEWATER

Industrial wastewaters containing petroleum hydrocarbon is highly toxic and posed a great danger especially to refinery nearby communities. Therefore, there is need for effective treatment before discharge. Natural process employing microorganisms is considered to be very effective and environmentally friendly method of decontamination. This research is mainly focused on the use of indigenous microbes in biodegradation of petroleum hydrocarbons in contaminated water. The wastewater was characterized for physicochemical, organics, inorganics and metallic parameters. The ability of Serratia mercescens, Bacillus subtilis, Micrococcus luteus, Bacillus cereus and biostimulated samples were studied for the hydrocarbon reduction from petroleum refinery wastewater. The performance of the system was measured by monitoring chemical oxygen demand (COD) reduction and increase in optical density (OD) of the flask cultured samples in Bushnell-Haas medium. Bacillus subtilis demonstrated high COD reduction of 56.19% while Micrococcus luteus reduced COD by 52.43%. Micrococcus showed higher growth in the Bushnell-Haas medium with the refinery wastewater as a sole carbon source.