A Comparative Study of the Bioremediation Potentials of Inorganic Nutrient Sources

Aim: To evaluate the efficacy of inorganic nutrient sources in crude oil degradation.

Place and Duration of Study: The study was carried out at Environmental Microbiology Department, University of Port Harcourt, Nigeria, between January and June 2015.

Methodology: Hydrocarbon polluted soil was collected and recreated in three (3) containers marked A – C, representing NPK, Urea fertilizer and control, respectively. The setups were amended with NPK and urea fertilizer and observed for a 35 - day period. Hydrocarbon degradation in a 0.25% crude oil contaminated water was as well studied by inoculating a mineral salt – water (solution) with suspensions of a 24-h old pure cultures of bacterial isolates identified as Pseudomonas sp., Bacillus sp. and Micrococcus sp. Total petroleum hydrocarbons (TPH) and total hydrocarbon content (THC) was analyzed using gas chromatographic analysis and mass spectrometer – GC/MS.

Results: The percentage residual petroleum hydrocarbons in soil were closely related to each other when compared to the control setup, C. NPK was however, found to be more effective in the aquatic environment than urea. The kinetics studies in water showed the treatment options were effective in the descending order of percentage residual hydrocarbons; direct NPK, Aw - (20.3%) > direct urea, Bw - (23%) compared to the control, Cw - (45.2%). And a one-way analysis of variance, the Laverne’s test for homogeneity of variances and Tukey post hoc test showed there was a significant difference in the mean values of the various treatment options (p>0.05, f (2, 36) = 92.70, PV = 0.00).

Conclusion: In the overall, the efficacy of a fertilizer depends on the environment it found itself. However, urea fertilizer was observed to be slow-release in nature, hence if fertilizers must be applied directly, urea fertilizer is recommended.