Slurry-Phase Bioremediation of Ogoni Land Crude Oil Contaminated Soil

Abstract

The contamination of soil originated from evolutional activities such as transportation and spillage, as in the case of Ogoni land in the Niger Delta area of Nigeria, and it is a well-known environmental problem in Nigeria. This study examined the capacity of two indigenous bacteria, Pseudomonas aeruginosa, and Bacillus subtilis to remediate the hydrocarbon contaminated soil. The focus of the work was to isolate, identify, and determine the extent of bioremediation achieved in the soil contaminated with crude oil in Ogoni land, which was used as a case study for the slurry-phase bioremediation process. These organisms earlier mentioned were identified based on their morphological and biochemical characteristics. The bacteria species were considered separately and in combination in a Laboratory-scale slurry-phase in a 14-day treatment period using 30 g of soil for each case. The performance of each batch bioreactor was compared to the sterile control. The slurry phase bio-reactor, RA, treated with Pseudomonas sp., had an actual degradation of 31%, the slurry phase bio-reactor, RB, treated with Bacillus sp., had a real degradation of 35%. The slurry phase bio-reactor Rc, which contain both microorganisms had an actual degradation of 36%, the slurry phase bio-reactor RD had a real degradation of 0%. The results obtained confirm that the isolated bacterial from the soil can effectively utilize contaminating crude oil as a source of carbon and energy. The decrease of hydrocarbon in the sterile control was used as a basis for comparison of the petroleum hydrocarbons lost through the extraction process as microbiological activity was not possible. Results from the study have shown that P. aeruginosa and B. subtilis strains were effective for the slurry-phase bioremediation of hydrocarbon contaminated soil.