Bioremediation of a crude oil polluted tropical rain forest soil

Abstract

A combination of options including Biostimulation with agricultural fertilizers, Bioaugumentation and physical processes were evaluated in-situ in the clean-up of crude oil polluted tropical rain forest soil for a period of nine weeks. Soil physicochemical parameters such as moisture (19% to 13%), pH (6.34 to 4.5) and organic carbon (85% to 1.5%) dropped during the remediation treatment. Total Nitrogen increased (0.021% to 0.081%) with increase in period of remediation. There was an increase in the total heterotrophic bacterial (THB) and hydrocarbon utilizing bacterial (HUB) counts in all the remediation options throughout the period. The control site O (no treatment employed) revealed no significant hydrocarbon loss (2%) within the study period. The hydrocarbon losses (73% to 88 %) experienced in five other options were significantly different from the control. Option A (a combination of Biostimulation and Bioaugumentation with indigenous HUB, hot water washing and tilling) recorded a hydrocarbon loss of 83%. Option B (a combination of mixing uncontaminated soil from a different location with polluted soil, tilling and Bioaugumentation with indigenous hydrocarbon utilizing bacteria) produced the lowest level of hydrocarbon loss (73%). Option C (a combination of Biostimulation, Bioaugumentation with indigenous HUB) recorded the highest level of hydrocarbon loss (88%). Option D (a combination of Bioaugumentation with genetically engineered strains of hydrocarbon utilizing Pseudomonas, Biostimulation and tilling) produced a hydrocarbon loss of 82%. Option D1 (a combination of Biostimulation with tilling) produced a hydrocarbon loss of 86%. These results suggest that Biostimulation with tilling (nutrient enhanced in-situ bioremediation) and or the combination ofBiostimulation and Bioaugumentation with indigenous hydrocarbon utilizers would be effective in the remediation of crude oil polluted tropical soils.



Key Words: Bioremediation, Bioaugumentation, Biostimulation, Hydrocarbon, Fertilizer

[Global Jnl Environ Sci Vol.2(1) 2003: 29-40]