Cation Exchange 1D

This example is from PHREEQC-3 documentation [Parkhurst and Appelo, 2013].

The following example simulates the chemical composition of the effluent from a column containing a cation exchanger [Appelo and Postma, 2005] Initially, the column contains a sodium-potassium-nitrate solution in equilibrium with the exchanger. The column is flushed with three pore volumes of calcium chloride solution. Calcium, potassium, and sodium react to equilibrium with the exchanger at all times. The problem is run two ways—by using the ADVECTION data block, which models only advection, and by using the TRANSPORT data block, which simulates advection and dispersive mixing.

Schematic for example 11

Schematic for example 11 in Parkhurst and Appelo [2013]

Fast path

You can try if rtfmf6 works on your machine. Download all input files. Unzip them and change into the directory cation_exchange_1d. Type rtmf6. This is equivalent to the steps 1. through 5 in Work flow.

Work flow

These are steps to create the input files, run the model, and look at the results.

  1. Create MODFLOW 6 Model with FloPy (uses FloPy but could be done with any GUI tool that supports the creation of MODFLOW 6 flow and transport models)

  2. Create a TOML config file

  3. Define PHREEQC solutions for initial boundary conditions

  4. Assign solutions to MODFLOW 6 cells with native input file syntax

  5. Run rtmf6

  6. Look at the Results