Biostimulation of Used Engine Lubricant Polluted Soil Amended with Pig Dung

The environment is polluted by hydrocarbons when used motor oils are spilled. Studies were carried out to investigate the bioremediation potential of pig dung in a soil polluted with spent engine oil. Top soil (0-15 cm depth) samples were randomly collected from areas with history of spent engine oil pollution within Anyigba, Kogi State, Nigeria. One kilogram of the polluted-soil was measured into each of nine plastic containers. Pig dung collected from the Prince Abubakar Audu University, Anyigba, was standardly prepared and mixed with the soil at the rate of 0, 50 and 100 g kg-1 soil in triplicate. The experiment used a completely randomized design. Soil samples were taken from each container at 0 and 28 days for hydrocarbon utilizing bacteria and total petroleum hydrocarbon determination using standard methods. Data obtained from the experiment were subjected to descriptive and inferential statistics. The species identified were Enterobactersp, Escherichia coli and Bacillus sp, with Bacillus sp. being the most predominant isolate. The total petroleum hydrocarbon (mgkg-1) of the soil on day 0 was 59.78 ± 1.84. After the amendments (at control, 50 and 100 g kg-1), the total petroleum hydrocarbon (mgkg-1) values were 44.92 ±2.26, 35.52 ± 0.71 and 29.57 ± 2.99 at 28 days respectively. Pig dung and the high level carbon utilizing bacteria, Bacillus sp, significantly enhanced the biodegradation process as an impressive 50.54% remediation efficiency was achieved 28 days after amendment in soil treated with 100g of pig dung. It is recommended that a biodegradation strategy that uses pig dung and Bacillus sp be employed in the clean-up of used engine lubricant polluted soils.