Bioremediation study of a hydrocarbon-contaminated soil by profiling aromatic and aliphatic chains

Efficient decontamination of oil contaminated soils is not always easy, especially when the contamination is aged. In this work, we have opted for bioremediation techniques, with a low environmental impact, whose treatments were selected according to the area and soil to be treated. Thus, an industrial area, which had had fuel oil spills for decades, was our decontamination target, using bioremediation techniques that included bioaugmentation with bacteria (autochthonous bacterial consortium), phytoremediation with a plant (Medicago sativa L.) and bioaugmentation with a fungus (Pleurotus ostreatus). These treatments were tested alone and in combination to observe any possible synergies. The evaluation of these treatments for the degradation of the total aliphatic and aromatic fractions of total petroleum hydrocarbons (TPH), showed a higher efficiency (18–48 %) in the degradation of the aliphatic fractions for all the treatments compared with natural attenuation (11 %). By contrast, lower efficiencies were obtained for the aromatic fractions (0–35 %) compared with natural attenuation, which did not decrease. The removal of these fractions was only effective in the combined treatment using all three organisms: the plant, the bacteria, and the fungus, where the bioaugmentation enhanced the plant-microorganism interaction in the root system. The selection of the biological treatments to a specific contaminated site and the evaluation of decontamination by the aromatic and aliphatic chain profiles, leads to a better understanding of the degradation of the different fractions of fuel.