Department of Geosciences
North Dakota State University
AQUEOUS GEOCHEMICAL MODELLING
Input for WEB-PHREEQ is form-based, that is, you enter data into the spaces provided. In some cases, you may need to choose a particular chemical species using drop-menus. For example, you have a choice of entering sulfur data as S, SO42-, or H2S.
On the first page, you have the following choices:Simple speciation v.s Advanced speciation
The "advanced" page allows the user to make calculations over a range of variable values. For example, you might wish to calculate silica solubility over a temperature range of 25 to 100 degrees C in 50 steps. The "advanced" page lets you save selected output of these calculations to a compact file that is easily imported to a spreadsheet or plotting program.
Single solution vs. Mixing of two solutions
Choose whether you wish to do calculations for a single solution, or whether to mix two solutions using phreeqc's MIX keyword.
There are also three databases to choose from: "phreeqc", which is the default database, "wateq4f", or "minteq." Each has different choices of input parameters that may be applicable to your problem.
On the second page, by checking the "input" box at the bottom of the input screen, you have the option to view the input file generated by the web interface.
Notes on input:
Acknowledgments:WEB-PHREEQ is part of an instructional module for Geochemistry 428/628 at North Dakota State University. Thanks to Sandy Sprafka for obtaining initial funding for this project, and to Andrew Yahin for the coding. Version 2 of WEB-PHREEQ was coded by Tim Mooney, though certain sections of code are largely untouched from the version 1 code.
Many thanks to David Parkhurst and his crew for developing PHREEQC. This web implementation © B. Saini-Eidukat, Andrew Yahin, and Tim Mooney.
Saini-Eidukat, B. and Yahin, A., 1999, Web-phreeq: a WWW instructional tool for modeling the distribution of chemical species in water, Computers & Geosciences, Volume 25, Issue 4, p. 347-353, ISSN 0098-3004, DOI: 10.1016/S0098-3004(98)00138-1. (http://www.sciencedirect.com/science/article/B6V7D-3WS6D6F-6/2/581b3dc8fc759c13aaf6fd0c9cb3c16d)