Jia Wang

Hello, With the flash diagram setting, the fluid defined in the Reactants pane is mixed with the fluid defined in the Basis pane at all fractions. This means that at a mixing fraction of 0.4, this is a mixture of 40% of the fluid in your Reactants pane (freshwater) and 60% of the fluid in the Basis pane (groundwater). At a mixing fraction of 0, it is simply the fluid defined in the Basis pane. To see a detailed example of the flash configuration, please see the Fluid Mixing and Scaling lesson on the GWB Academy and section 3.8 Flash diagrams in the GWB Reaction Modeling User Guide. If you would like to compare mixing between GSS and React, I would suggest that you make sure the correct proportions are used in GSS. I noticed that a reactant times factor of 100 was set in your React run. The mixing fraction calculation would account for the reactant times factor in React but you would need to set the volume (or mass) of each fluid directly in GSS. If the mixture is in the same proportion between GSS and React, they should show the same results. Hope this helps, Jia Wang Aqueous Solutions LLC

Hello Cheng, I am glad to hear that you were able to resolve the previous issue with tetracycline. The input file you have provided has precipitation disabled. In this case, the program will report the number of phases supersaturated at each step and the name of the mineral most saturated. This is by design and not an error. If you would like to enable precipitation in your reaction, you would need to change the setting under the Config menu. In GWB 12, the option for this is Config --> Iteration. For more information on this mineral precipitation, please see section on 2.3 Initial System in the GWB reaction Modeling User Guide. The mass imbalance error in this case is due to the small mass difference between the program's calculation and the mole weight entered for some entries in the dataset. Once I corrected the mole weights for these entries (482.4500 for Ca(TC--) and 483.4500 for Ca(TCH-)+), the mass imbalance warnings were resolved. I believe you would find the TEdit application from the latest GWB version very helpful in checking your customized datasets. The latest version of TEdit reports potential errors at the time of dataset read in. You can access the latest version of TEdit with a paid subscription or a free GWB Community license. Please note that the GWB Community version will only allow you to save your dataset in the latest format, which would not be backwards compatible with GWB 12. Hope this helps, Jia Wang Aqueous Solutions LLC

You're welcome. Hope the rest of your project goes well. Best, Jia

You're welcome. I am glad that was helpful.

Hello, Gtplot is not currently able to plot multiple models in one window. However, you can save the result with each run with a different suffix every time you adjust the concentration of Na. You can plot the result in a new Gtplot window without overwriting the previous run. The suffix can be adjusted in the Output dialog under the Config menu. Best regards, Jia Wang

Hello Adam, You're welcome. I am glad to hear that was helpful. Best, Jia

Hello, Gtplot reads in an xml type file (ends with extension .gtp) to create plots. Like you described, Gtplot allows you to plot XY plots and export numerical data from each variable type. You can select multiple options within the variable type (e.g. Ca++, HCO3-, Na+, etc under Species Concentration) and export all the selected options' numerical data. However, Gtplot does not allow you to select more than one option under the same variable type with different units (e.g. porosity and permeability) at the same time. In this sense, there is not really any way to support the selection of all data read in by the plotting application and export them into tab delimited form. If you are familiar with coding, you can parse the text output file (would be something like React_output.txt) for data you want at time steps throughout the simulation. At each time step, the program writes out the data related to the equilibrium state solved. You can control what gets printed to this file in the Output dialog (go to Edit -> Output...). For more information on the output dialog, please see section 2.9 Controlling the printout in the GWB Reaction Modeling User Guide. In the same Output Dialog, you can also select the XML file type to be character instead of binary. You can rerun your simulation and open the plot file .gtp directly in a text editor (e.g. notepad) to see the data being pulled in by Gtplot. This adds the option for you to parse the xml file for the data you need instead of the text file React prints. Best regards, Jia Wang Aqueous Solutions LLC

Hello, The GSS spreadsheet allows user to add bulk component concentration as basis species. In this case, I think you are very close with the idea of adding the bulk amount of HCO3- and CO3-- as your carbon component represented by the HCO3- entry. If you want, you can select the unit for HCO3- as mg/l of carbon. That way, you can calculate the bulk elemental equivalents of carbon in your system (from HCO3- and CO3--) and enter that value directly into the spreadsheet. You can see an examples of concentrations entered as elemental equivalents in Example2.gss in the Scripts folder that comes with the GWB installation. Hope this helps, Jia Wang Aqueous Solutions LLC

Hello Cheng, If you have corrected the log K value for TC--, then it would match the data table you have posted earlier. I am not seeing any particular issue with your GWB input file setup. I am not sure how your Minteq file is set up, so it would be difficult to know whether your GWB file is set up the exact same way. Is there any additional information from the original reference paper regarding the model set up or software used originally? If you are using Minteq as a comparison, I think you might consider adding your reactions to thermo_minteq.tdat and use this customized dataset. Thermo_minteq.tdat will use the same activity model as Visual Minteq, whereas thermo.tdat uses the bdot activity model. I don't think this is going to make a huge difference for your calculation. For more information on different activity models, please see the Activity Coefficients chapter in the GWB Essentials Guide. If you don't intend to simulate adsorption, then you can simply remove the Kd surface dataset loaded. If no surface dataset is loaded, the GWB will not consider sorption reactions. Also, note that loading the Kd surface dataset without providing any mineral mass or inert mineral volume, then no sorption reaction takes place. I don't think this is the reason for the difference between your GWB result and reference figure but it will help to simplify your input file. More information on sorption models in the GWB Essentials Guide. Best, Jia

Hello Cheng, I took a quick look at your custom thermo dataset and found that your reaction for TC2- log K, 9.3, which did not match the negated value given in your table. Once I changed the value to 16.57 and reran your calculation, the result seems to match what is shown in your excel plot. I also noticed that you have loaded a Kd sorption dataset for your React simulation. Perhaps I don't have your customized Kd file for the run, but unless you add the desired species reactions into the surface datasets, the GWB won't perform any sorption reaction. In this case, your React run is not affected by the surface dataset you have loaded. For more information and example for sorbing, please see section "Sorption onto mineral surfaces" in the GWB Essentials User Guide. Hope this helps, Jia Wang Aqueous Solutions LLC

Hello, If I understand correctly, I think you can simplify your setup by adding a reaction path for the second component that you wish to model surface complexation with. Since your reaction rate for your Fe(OH)3(ppd) is 0, the kinetic mineral is simply there to provide a surface. There's no dissolution or precipitation of the mineral. In this case, when you trigger your run, you are just calculating a static speciation calculation in your fluid. I would suggest that you set the other component that you would like to sorb (Cr or Sb) in the basis at an extremely small concentration (like 1e-25 mol/l). In the Reactants pane, set up a simple reactant of the second component you like to sorb and set the quantity you want to titrate in (1e-5 mol/l). When you trigger the calculation using the go command, you can look at the result at the start of your simulation vs the end. For example, in SC.rea, you would add in CrO4-- to your basis at a really small concentration and then in the Reactants pane, add in the endpoint amount as a simple aqueous reactant. Also, in the SC.rea file you attached, Cr+++/CrO4-- is decoupled, so you should be adding in CrO4-- directly and not swapping. Please double check that you are using the same file as you uploaded. Hope this helps, Jia Wang

Dear Zixuan, If you would like for the software to distribute the component concentration you set in the basis between the fluid and sorbed surfaces, please use the sorbate include command. By default, the concentration you set would only be the portion in the fluid. The software will populate the corresponding amount sorbed in the surfaces in equilibrium with the amount in the fluid. When you do a pickup command, the sorbate include parameter is reset and therefore you have to enable it again before your second run. I suspect that this is your problem. Best regards, Jia

Hello Frank, Thank you for providing clarifications. You can definitely load in multiple ion-exchange datasets with a different name for each exchange site like you described above. If your mineral volume is not changing, you can set an absolute value for the exchange capacity instead of that eq per grock. That way, the capacity is not affected by the mass of minerals you have present in your system. Just one more note. To load multiple surface datasets of the same model type, make sure that a unique identifier is set for the "Surface type". This is the third line from the top of the file and by default set to IonEx when you create a new ion-exchange dataset. For example, the default dataset header lines look like: For example, the default dataset header lines look like: Dataset of surface reactions for gwb programs Dataset format: may20 Surface type: IonEx Model type: ion-exchange gaines-thomas Changing the surface type to a unique identifier by adding _Y: Dataset of surface reactions for gwb programs Dataset format: may20 Surface type: IonEx_Y Model type: ion-exchange gaines-thomas Hope this helps, Jia

Hello Frank, Unfortunately, unlike the two layer and three layer surface models, ion-exchange datasets do not have exchange sites that can be linked to specific minerals. I am not sure the exact problem you're investigating, but if you want to model exchange on just one mineral at a time, you can load in the ion-exchange dataset prepared with the corresponding mineral swapped into your system. Then repeat with another mineral and the corresponding ion-exchange dataset. You can specify the cation or anion exchange capacity in terms of total electrical equivalents or electrical equivalents per mass of rock, in which case the program multiplies this value by the total mass of equilibrium and kinetic minerals, as well as inert mineral mass. Hope this helps, Jia Wang Aqueous Solutions LLC

Dear GWB12 users, We are pleased to announce our latest maintenance release for GWB12, GWB 12.0.9. The 12.0.9 update provides support for Python 3.8 and later; avoids runaway behavior when dragging multiple files into a GWB window, fixes Rxn clipboard command, corrects issue transporting kinetic colloids when multiple surface types are active, adds minor updates to GSS and Phase2, and provides fixes for all known issues Update from 12.0.0-12.0.8 at no charge to ensure you have all the newest features and bug fixes. Existing installations should automatically update to this release, unless auto-update is disabled. In that case, users should update their installations from the Help menu of any GWB app. Regards, Jia Wang Aqueous Solutions

Hello, I am sorry to hear that you're having issues with Gtplot. Could you please provide a bit more information regarding the error. Did this issue occur when you try to open an existing .gtp plot file from GWB 15 and earlier? If so, could you please try rerunning the original input file and try launching Gplot from the Results pane? Does it make any difference if you place the input file in a new folder, run the input file, and launch Gtplot from the Results pane? If that didn't resolve the issue, please provide a screenshot of any error message and your Gtplot window. Best regards, Jia Wang Aqueous Solutions

Hello, Did you successfully install the GWB True type font after downloading it from the website? You should be able to open the font file and hit "Install". You may need to restart your computer after the installation is complete. Please see the step by step resolution on this page: https://www.gwb.com/installation_troubleshoot.php#RESOLUTIONS Best regards, Jia Wang Aqueous Solutions LLC

Hello Andrea, I’m sorry to hear you are having issues with the GWB font. Please download and then install “GWB Symbol Ext” Font directly using this link: https://www.gwb.com/font.php You may need to restart your computer after installation. Hope this helps, Jia Wang Aqueous Solutions LLC

Hello Zixuan, You're welcome. I hope the rest of your project goes smoothly. Best regards, Jia

Hello Benjamin, Thank you for sharing PyGCC with the GWB Community. I have sent you a message at the email address that you have listed for the forum. If you didn't receive the message, please check your spam folder. Best regards, Jia Wang Aqueous Solutions LLC

Hello Zixuan, Thank you for the clarification. I think there was some issue with the forum with adding extra characters to the title of your surface dataset. I think you have attached the right surface file. My apologies for that. I was able to reproduce the error in GWB 2021 when I tried to pick up the fluid. I believe this error is fixed in the latest release GWB 2022. To get the update, click on the Check for updates tile under the Support tab in the GWB 2021 dashboard. Once your GWB has been updated, please try repeating your calculations again. Just a one more thought for your consideration. I noticed that you have swapped in redox species (Fe+++ and CrO4--) into your Basis pane. Please note that swapping in a redox species does not decouple it from its basis species, therefore the total concentration specified for that component is still being distributed across various species of redox states. For example, React will find the equilibrium distribution of mass between all ferrous and ferric species given the bulk concentration you specified in the Basis pane. If you would like to constrain the mass for each oxidation state separately, then you should decouple the redox reaction under Config -> Redox Couples.... Once you have done so, you can add in the redox species from the "add" dropdown menu. For more information about redox couples, please see section 2.4 Redox couples and 7.3 Redox disequilibrium in the GWB Essentials User Guide. Hope this helps, Jia

Hello Zixuan, I wasn't able to reproduce the same error by running your input file. Could you please double check that you attached the correct React file and surface dataset? The React script you attached loads the surface dataset "IN6+OU1 num2.sdat" but the one you attached is "1269196283_IN6OU1num2.sdat". Best regards, Jia

Hello, Just a few more thoughts for your consideration. The SIT dataset accounts for fluids where the dominant electrolytes are Na+, Cl-, K+, ClO4-, and NO3-. Interaction parameters are provided for these major electrolyte ions to work accurately at higher ionic strength. Since your fluid is dominated by sulfates and uranium, this dataset doesn't have the interaction parameters for these species to account for speciation at the higher ionic strength as you were expecting. I should clarify that when swapping in As and Se species, the concentration should be constrained with equivalent concentrations. You can do so by finding the elemental concentration matching the original constraint and then using the "as" unit, similar to what you have done for H2(PO4). Also note that since there are fewer U species in this model than Minteq's database, so I suspect the ionic strength is going to be relatively different. You might also want to consider the various redox equilibria / disequilibria for each redox component to make sure that couples are decoupled appropriately. When you add a redox species in GSS, the redox species is automatically disabled in your SpecE8 calculations. If you can post your PhreeqC script, we can take a look to see how it is setup compared to your GWB input script. Best regards, Jia

Hello, I suspect the reason that you are not able to calculate the species activity for Cu++ is because the required constraints aren't provided. In thermo_minteq.tdat, Cu++ is a Basis species and Cu+ is a redox species. Assuming that you have added Cu+ to your dataset, you have disabled the redox equilibrium between Cu++/Cu+. In this case, you won't be able to calculate any species involved with the oxidation state of Cu++ unless you also include a concentration for the Cu++ component. If your concentration entered is the total concentration for all copper species, you can use Cu++ instead of Cu+. In this case, if you also enter a constraint for the oxidation state (e.g. Eh, pe, or O2(aq)) and H+ (or pH), then SpecE8 will be able find the equilibrium mass distribution between all cuprous and cupric species. For more information about redox couples, please see section 2.4 Redox couples and 7.3 Redox disequilibrium in the GWB Essentials User Guide. Hope this helps, Jia Wang Aqueous Solutions LLC

Dear GWB users, GWB 2022 is here and so are solid solutions! You can model Guggenheim and ideal binary solutions with continuous or discrete implementations. Plus, get real-time plot updates from GSS datasheets, the new CEMDATA thermodynamic database, exchange reaction kinetics, and much more! Supported subscriptions upgrade automatically within three days. Or click “Check for updates” on the GWB dashboard. GWB Community users can request a new license through our webstore. Not yet a subscriber? There is no better time to subscribe or upgrade that old GWB license to a subscription. Order now or contact us for a same-day quote. Sincerely, Jia Wang Aqueous Solutions LLC