How to input system parameters in X1t

[hayleycas]

I am trying to simulate the pumping of a waste water into an aquifer and am attempting to do this via X1t as I want to specifiy flow rates and time components. As well as elemental composition I want to be able to specify system parameters such as TDS, EC and Alalinity but these are not options under the "add" button.

 

Is it possible to add other elements and parameters that are not in the drop down menu? If so how do I do this?

[Brian Farrell]

Hi,

 

GWB can calculate TDS automatically for your Initial and Inlet fluids (and Inject in X2t). You can also specify TDS in mg/kg for each scope from the GUI (near the bottom) or the command line. TDS is important for converting units internally within the program. You can set carbonate alkalinity to constrain total HCO3- concentration. Add HCO3- to the Initial, Inlet, or Inject pane, then change units to mg/kg_as_CaCO3, or something similar. To set the alkalinity, you must specify pH explicitly.

 

Do you have a reason for wanting to specify electrical conductivity? This is something that can be calculated in GWB based off the free species concentrations of a few major ions (over a limited T and Ionic strength range).

 

You can add new elements (as new basis species) to the drop down menu by modifying the thermodynamic dataset (you'll also want to add new minerals, gases, aqueous and surface species which can be formed from the new basis species).

 

I would check out the User's Guides for more info on each of these. Look for the TDS and alkalinity commands in the X1t section of the GWB Reference Manual. You can also find the Thermo Data Appendix in that same manual.

 

Hope this helps,

Brian Farrell

Aqueous Solutions LLC