Effectiveness of bioremediation process in hydrocarbon - contaminated soils

Abstract

The present study was undertaken to evaluate the efficacy of introduced indigenousbacterial isolates for ex situ bioremediation of fuel oil contaminated soil. For this purposethree hydrocarbon-degrading indigenous bacterial isolates were screened from petroleumoil contaminated soil and repeatedly used for inoculation of fuel oil contaminated soil.The total petroleum hydrocarbons (TPH) content was determined by gravimetric method,Hydrocarbon fractions (alkanes, aromatics, asphaltenes and resins) present in TPH wereobtained by silica gel column chromatography. The study showed that some introducedbacterial isolates effectively adapted to the contaminated soil. The bioaugmentation effectwas calculated to raise the numbers of bacteria by approximately one order of magnitudefrom the indigenous population at the site. Ex situ study showed that the introducedbacterial consortium effectively adapted to the local environment of the soil at thebioremediation site.Our results indicated that disappearance of TPH from inoculated soil samples dependedon the general soil impurity, term of bacterial treatment, level of TPH contamination andindividual microorganism efficacy. With application of bacterial consortium andfertilizers, the TPH level was reduced to 60 - 66% after three months.