Comparative evaluation of different bioremediation techniques for crude oil-contaminated soil

The present study aimed to establish, using the bioremediation technique, the most efficient treatment strategy for remediation of a sandy soil that is artificially contaminated with light crude oil. The experiment was conducted for 180 days to monitor the biodegradation of oils and greases (OG's), aliphatic hydrocarbons (AHs), and polyaromatic hydrocarbons (PAHs). The removal of these compounds was evaluated using three different strategies, the addition of nutrients (III), addition of a biosurfactant produced from Pseudomonas sp. (IV), and the addition of the biosurfactant plus nutrients (V). The remediation strategies were compared with the control containing only soil (I) and the control with natural crude oil attenuation (II). At the end of the study, it was observed that the strategies III and V showed the best OG's removal rates, i.e., 90.40% and 78.00%, the best AHs removal rates, i.e., 96.82% and 98.35%, and best PAH removal rates, i.e., 83.58% and 72.3% respectively. Based on the above results, it was concluded that the bioestimulation methods are important tools in the remediation of the environment impacted by oil spills. In addition, the study suggests that the knowledge of the native microbiota is important to improve the efficiency of these bioestimulation techniques.