Using Continuum Approach to Quantify the Remediation of Nonaqueous Phase Liquid Contaminated Fractured Permeable Formations

Abstract

This study addresses the feasibility of using a continuum modeling approach to simulate pump-and-treat remediation of nonaqueous phase liquid (NAPL) contaminated fractured permeable formations. A simplified discrete fracture model, which incorporates permeable blocks with embedded parallel equidistant constant aperture fractures, was used to simulate the NAPL dissolution in an idealized fractured permeable formation. The applicability of this model is defined by the ranges of a dimensionless mobility number and interphase mass transfer coefficient. A continuum based model able to simulate phenomena predicted by the discrete fracture model has also been used. Three dimensionless parameters referring to organic solute advection and dispersion, and the continuum interphase mass transfer coefficient govern the performance of the continuum model. The nonlinear relationships between the discrete fracture and continuum model have been identified and formulated. However, the simplified conceptual models of this study may be inapplicable to many types of fractured formations. Ranges of possible use of the continuum modeling were determined in terms of dimensionless parameters. The discrete fracture and continuum approaches of this study can be useful for the preliminary evaluation of ideas concerning optimization of the remediation of NAPL contaminated fractured permeable formations.