Chiang Mai Journal of Science

Groundwater contamination by dissolved organic compounds such as Non-Aqueous Phase Liquids or NAPLs (e.g. gasoline or chlorinated solvents) is a common environmental problem that increasingly gains attention among scientists, engineers, and practitioners. Locating NAPL sources and their extent, cleaning up the aquifers, and predicting mass transfer and transport of contaminants of this kind are difficult tasks. Experimentally validated numerical model that can be readily used to assess or predict dissolution of NAPL in heterogeneous subsurface environment is very limited. This work presents an initial development and validation of a finite-element based numerical model that is capable of simulating simultaneous mass transfer or dissolution of entrapped NAPL and advective-dispersive transport of the dissolved constituent in the groundwater environment. A one-dimension Crank-Nicolson Finite Element Galerkin code (CNFEG) was developed [1] and validated using dissolution data obtained from column experiments. Nonlinear regression technique is also used in the validation process and results were used to assess statistical significance of hydrodynamic on mass transfer processes.