Simulation of nonaqueous phase groundwater contamination

Simulation of groundwater contamination by nonaqueous phase contaminants requires solution of the multiphase flow equations for a porous medium. A three phase, two dimensional, one component nonaqueous model is developed. The contaminant can partition between the air, water and nonaqueous phase. An adaptive implicit method is used to discretize the equations. A variable substitution method, which takes into account subregions where the nonaqueous phase is nonexistent, is employed to more efficiently solve the model equations. A detailed discussion of the boundary conditions is also presented.