Comparing approaches for modelling natural attenuation of organic compounds in heterogeneous porous media

摘要

Assessing natural attenuation using a three-dimensional Eulerian transport model generally requires a high resolution of parameters and is consequently prohibitive with respect to the computational effort. An alternative to a fully three-dimensional Eulerian model is a computational highly effective one-dimensional Lagrangian transport model concept. In this model integral mass fluxes across control planes are considered instead of single point concentrations. Consequently, measured mass fluxes can directly serve as model input. In this paper a model comparison of a CPU-intensive three-dimensional Eulerian transport model with the faster one-dimensional Lagrangian model is presented. Since the fast Lagrangian model concept employed here is based on spatially invariant reactive transport parameters, a fundamental aim of the comparison is the determination of a "scale of effective homogeneity". For transport distances beyond this scale it is postulated that neglecting the spatial variability of transport parameters is justified.