Numerical simulation of groundwater contamination by ethanol-amended gasoline

This paper presents a numerical procedure for simulating the dispersion of ethanol-amended gasoline in ground water flows. In this problem the degree of influence of the ethanol in the biodegradation of the BTEX compounds is not known, since the common models does not include the presence of ethanol. The transport equation includes the dispersion, advection, sorption and biodegradation of the compounds BTEX and ethanol carried by the flow of water modeled using the Darcy’s equation for porous media flow. The mathematical model is solved using the finite volume method with a first-order decay mode for the biodegradation. It is assumed that the hydrophobic organic compounds solubility in the aqueous-phase increases log-linearly with the presence of ethanol, in a phenomenon called the “co-solvency effect”. The sorption phenomenon (retard of the plume) is modeled using linear equilibrium isotherm. To evaluate the model and demonstrate its potentialities, it is solved some groundwater contamination problems with ethanol-amended gasoline.