Reactive Transport - Reference

Several reaction processes can be added to the solute transport calculations including

·         Sorption and desorption,

·         Degradation, and

·         Plant uptake.

In the saturated and unsaturated all three of these processes are available. However, in the overland flow only degradation is available, but in MIKE Hydro River advanced reactions are possible using MIKE ECO Lab, which is a general equation solver for any kinetic reaction process.

The conservative transport of solutes in the unsaturated zone and in the groundwater is governed by the normal advection-dispersion equation described in Equation (33.3). When processes, such as sorption and decay, are included, the equation is extended to

(34.1)   

where r_b is the bulk density of the porous medium, q is the porosity of the porous medium, c* is the mass of solutes sorbed per dry unit weight of solid and the term dc/dt on the right hand side is a term indicating a biological or chemical reaction of the solute.

This way of describing reaction processes is very simplified and, in some cases, may give incorrect results. Nevertheless, it is a very common way of describing the reaction processes in hydrologic systems.