BIOLOGICAL REMEDIATION OF CRUDE OIL CONTAMINATED SOIL

Crude oil contamination is one of the major environmental problems effecting aquatic and terrestrial environments. At present, approximately 80% of lands are affected by petroleum origin products. The aim of this is biological remediation of crude oil contaminated soil using microorganisms. Among other objectives were to collect, preserve and culture the microorganisms; to assess the physical and chemical properties of the soil before and after remediation; to determine the efficiency of microorganisms at different temperatures. The crude oil was obtained from Sterling Global, an oil and gas exploring company in Eastern Obolo Local Government Area, Akwa Ibom State. The collected sample were properly handled to avoid contamination. The soil was artificially contaminated with crude oil at a ratio of 20:80. After contamination, the microorganisms present in the soil were identified and cultured. Physical and chemical properties of the soil were assessed including Total petroleum hydrocarbons before and after remediation. From the result of the laboratory analyses, the predominant microbes responsible for bioremediation identified were Hydrocarbonoclastic bacteria, Pseudomonas and Bacillus at over 1000 count. TPH of 28.62%, 31.5% and 29.87% removal were observed in a constant 20% crude-oil-contaminated soil sample 1, sample 2 and sample 3 within 28 days of remediation period. The results of physical and chemical properties of the contaminated soil assessed generally improved after the bioremediation. Finally, the three predominant microorganisms (Hydrocarbonoclastic bacteria, Pseudomonas and Bacillus) assessed were numbered above 1000 and were very active at temperature ranged between 15 to 25 degrees Celsius. Among other recommendation, we recommended that the physical and chemical properties of the soil including total petroleum hydrocarbons should be assessed after 28 days to check the efficiency of the remediation process.