Abstract for: Modeling the Bioremediation of a Diesel-contaminated Soil Using an Enriched Hydrocarbon-degrading Inoculant

Contamination of soils with hydrocarbons is one of the most important threats for soil environments and the development of remediation procedures is being object of many research efforts. Bioremediation is an environmentally-friendly alternative, cheaper and less invasive than conventional engineering-based soil decontamination procedures. A model was developed to simulate the bioremediation of a diesel-contaminated soil slurry in a mixed closed batch system, using an enriched diesel-degrading bacterial inoculant. Mass transfer processes of desorption of diesel from soil to water and volatilization from water, and biodegradation by bacterial inoculant were included in the model, using complex Weibull sigmoid, first-order, and logistic/Monod kinetics, respectively. Model parameters were estimated from desorption abiotic experiments and previous biodegradation experiments in liquid media. Long-term model predictions indicated that, in the given conditions of biomass concentration, soil characteristics and diesel concentration, the contaminants could be practically eliminated from the system in less than 70 days. Sensitivity analysis of the model revealed the importance of maintaining a high biomass concentration in the system to improve bioremediation efficiency. Model was short-term validated with a biodegradation experiment for 360 h, during which near the 30% of diesel present in the system was eliminated. The developed model could be a useful tool to predict bioremediation efficiencies of different soil scenarios, by adapting the needed parameters to each system.