Bioremediation of Spent Engine Oil Contaminated Soils Using Indigenous Fungi Species

Abstract

Spent engine oil is derived from lubricating oil which has been used to lubricate various internal combustion engines and it is drained out for disposal during servicing of the engine. Spent engine oil causes great damage to soil and soil microflora when disposed indiscriminately. Thus, the bioremediation of spent engine oil contaminated soil was studied using indigenous degrading fungi isolated from hydrocarbon contaminated soils obtained from automobile mechanic workshops located at both Okpe and Uvwie Local Government Areas of Delta State, in the Niger Delta region of Nigeria. Three (3) fungi isolates with high engine oil biodegradability potential were used for the spent engine oil (SEO) bioremediation study. The fungi isolates used for the test were identified as, <em>Aspergillus glaucus</em>, <em>Trichoderma polysporum</em> and <em>Talaromyces flavus</em>using the API 20C method. The test microcosms were incubated for four weeks at 28 ± 2^oC. Physicochemical parameters such as, Sulphate concentrations, Total petroleum hydrocarbon, Nitrate concentrations, Phosphate concentrations, Total organic carbon content, pH and Hydrocarbon utilizing fungi counts were monitored weekly using standard ASTM methods to assess the biodegradation of the spent engine oil. At the end of the test duration, <em>Talaromyces flavus </em>recorded the highest percentage spent engine oil biodegradation (69.66%) for the 5% SEO experimental set up. Similarly, <em>Aspergillus glaucus </em>recorded the highest percentage SEO biodegradation (66.16%) for the 10% experimental set up. Thus, <em>Talaromyces flavus </em>and <em>Aspergillus glaucus </em>could be used to effectively bioaugment the bioremediation process of spent engine oil contaminated soils to restore the soil to its original state within a short period of time.