Hi Dr. Parkhurst: Over the past year or so you have been very helpful in answering questions regarding some specific questions I have had using PHREEQC to model geochemical reactions and transport. This model initially used a constant source term (representing acid tailing water) moving as one-dimensional advective flow through aquifer material containing native groundwater. I would now like to model the same situation, but by incorporating a decreasing source term. Is it possible to take the input solution (SOLUTION 0), run it for a certain number of shifts, then reduce the concentrations, say, 33%, run the new SOLUTION 0 for an additional number of shifts, reduce the concentrations again, and so forth? I would like the SELECTED_OUTPUT file to show the final concentrations in the last cell after a series of these solutions have been run. I have seen a limited number of smaller-scale examples of this problem. I am thinking that the basic set up for a 20 cell model with exchange and surface adsorption reactions (just for two solutions here) is as shown below. I was hoping you could provide some guidance and possibly take a look at my input file once I get it setup. My main concern is getting the SELECTED_OUTPUT and END statements in the right place so that I know the model is doing what I want it to do. Are the keywords in the following example in the right order? SOLUTION 0 #first inflow solution SOLUTIONS 1-20 SURFACE 1-20 EXCHANGE 1-20 ADVECTION -cells 20 -shifts (correponding to time for the first SOLUTION 0) END (needed here or not?) SOLUTION 0 #second inflow solution SOLUTIONS 1-20 SURFACE 1-20 EXCHANGE 1-20 ADVECTION -cells 20 -shifts (corresponding to time for the second SOLUTION 0) SELECTED_OUTPUT USER_PUNCH END ----------------------------------------------------- David B. Levy, Ph.D. Soil Scientist/Geochemist Shepherd Miller, Inc. 3801 Automation Way Suite 100 Fort Collins, CO 80525 Phone: 970.223.9600 FAX: 970.223.7171
Please note that some U.S. Geological Survey (USGS) information accessed through this page may be preliminary in nature and presented prior to final review and approval by the Director of the USGS. This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the sole responsibility of the user.
Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.
The URL of this page is:
Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
Visitor number 2896 since Jan 22, 1998.