Plume Behavior for Petroleum Hydrocarbon in a Tropical Sand Tank: Laboratory Experiments and Scenario-Specific Modelling

Numerical simulations were performed to assess the reactive transport and natural attenuation of gasoline fuel components in a 3-D sand tank model. The conceptual model includes a residual gasoline source that dissolves into the 3-D aquifer. The analysis reveals high to very high correlation between the observed and simulated values (average R2=0.97). A retardation factor R=1.5, and first-order decay rate of 0.0002/day were obtained from the model calibration for BTEX. The results are highly relevant in the light of the increasing awareness of the precarious trend of lack of monitoring and remedial feasibility data for the subsoil environment in the thousands of gasoline fuel stations, and petroleum storage/distribution underground infrastructure and the riverbeds of inland waterways in Nigeria. The biodegradation rate was the most sensitive model parameter, with about 82% increase in BTEX maximum plume concentration, for the zero biodegradation scenario.