SIMULATION AND AREAL INTERPOLATION OF REACTIVE SOLUTE TRANSPORT

Reactive solute transport in a spatially variable field is studied. Ad sorption is assumed to be described by the nonlinear modified Freundli ch isotherm with an adsorption coefficient that depends on pH and orga nic matter content. Assuming spatial variation of pH and organic carbo n content, a chemically heterogeneous field is simulated by the genera tion of a random field of the Freundlich adsorption coefficient. A thr ee-dimensional reference transport calculation is performed with the c omplete heterogeneous field as input. The effect of the sequence of ca lculations and interpolations, and of the size of the data set are exa mined. A CI (calculations before interpolations) and an IC (interpolat ion followed by calculations) procedure are defined. Attention is focu sed on the prediction of average solute breakthrough and on the predic tion of concentrations at specific locations. The results show that th e optimal procedure and data set size depend on the quantity of intere st. For the prediction of average behaviour, a smaller data set is suf ficient compared with the prediction of concentrations at specific loc ations. For the calculation of the average solute breakthrough a more efficient IC procedure can be used in combination with the smaller dat a set. If the concentrations at specific locations in the field are re quested, the size of the data set is more significant. However, for re latively small data sets a CI procedure performs better than an IC pro cedure.