2.2.1 Model Equations
Overall reactive transport in one-dimension was governed by the general advection-dispersion-reaction equation:
\(\frac{\partial\left(\text{θC}_{i}\right)}{\partial t}\ =\ \frac{\partial}{\partial x}\left(\theta D_{L}\frac{\partial C_{i}}{\partial x}\right)\ \ -\ \frac{\partial}{\partial x}\left(\text{θv}_{x}C_{i}\right)\ +\text{~{}θ}R_{i}\)(1)
For screening-level analysis, dispersion was neglected as dispersion is an empirical field parameter, simplifying Equation (1) to the following advection-reaction model:
\(\frac{\partial\left(\text{θC}_{i}\right)}{\partial t}\ =\ -\ \frac{\partial}{\partial x}\left(\text{θv}_{x}C_{i}\right)\ +\text{~{}θ}R_{i}\)(2)
Precipitation-dissolution kinetics of a mineral were described by the following chemical equation:
\(R_{i}=\left(\frac{A_{s}}{V}\right)k_{+}\ \left(1-\frac{Q}{K}\right)\)(3)
A glossary of terms and their units used in the above equations is presented in Table 1 .