Decontamination of Petroleum Hydrocarbon Contaminated Soils using Bioventing Technique

The fate of petroleum hydrocarbons in nature is of great environmental concern due to their toxic, mutagenic, and carcinogenic properties. A major decomposition process of petroleum hydrocarbons in the environment is microbial degradation. Polycyclic aromatic hydrocarbons (PAHs) are one of the most prevalent groups of contaminants found in soil. This research was carried out on phenanthrene (a 3-ring PAH) polluted soils decontamination in a solid phase reactor using synthetic contaminated soils with attribution of indigenous bacteria isolated from petroleum contaminated sites in Iran. Polluted samples was made of phenanthrene with three rates (100, 500, and 1000 mg/kg of soil) synthetically and was conducted with two bacterial consortium for a period of around twenty weeks. Ultrasonic machine and HPLC was applied for extraction and analysis of phenanthrene from contaminated soil samples. Microbial analyses were carried out using confirmative series tests, analytical profile index (API) kit tests and PCR. Results for phenanthrene biotreatment in solid phase revealed a significance relationship between concentration of phenanthrene and type of microbial consortium and type of soil with the removal efficiency over time of bioremediation (P value<0.001). According to the microbial analysis using complete amplified PCR and DNA extraction, among of Pseudomonas fluorescence, Serratia liquefaciens, Bacillus and Micrococcus strains that were as dominant bacterial consortiums in the contaminated soil samples, Pseudomonas fluorescence (pudita) was responsible to higher degree degradation of phenanthrene. Results showed that the microbial decomposition of the lower concentrations of phenanthrene needs shorter time compared with the higher concentrations. We can concluded that, the microbial treatment of oil hydrocarbons contaminated soils may considered as a feasible option in petroleum polluted sites in Iran.

Keywords:

Polycyclic aromatic hydrocarbons (PAHs) , bioremediation , petroleum hydrocarbons contaminated soils , PAH-degrading microorganisms , phenanthrene