Speciation and Saturation with High Saline Water

[Can]

I have an important question just came up from my co-worker;

We would like to perform a variety of speciation and saturation index calculation with geothermal water highly saline (like brine). Does GWB have capability to handle this composition of water in terms of activity coefficient calculations? How does (what equations) GWB utilize to calculate activity coefficients with waters that have high ionic strength?

Your immediate help or reference will be greatly appreciated in this matter.

Best Regards

[katezat]

Hello Can,

 

You can calculate activity coefficients using the B-dot model (an extended form of the Debye-Huckel equation), you can emulate the activity models used in other popular modeling programs (PHREEQC, WATEQ4F, or MINTEQ), or you can implement the virial methods (Pitzer equations) for better accuracy at high ionic strength.

 

For information on the different thermodynamic datasets distributed with the software, see section 2.3 of the GWB Essentials Guide and section 7.4 for more on the implementation of activity coefficients and activity models in The GWB. Chapter 8 of the Geochemical and Biogeochemical Reaction Modeling text includes more on estimating values for activity coefficients using virial methods.

 

Hope this helps,

 

Katelyn

Aqueous Solutions LLC