The Contaminant Treatment Systems dialog box is used to define the input for the Contaminant Treatment Systems (CTS) package in MT3D-USGS. The dialog box is displayed by selecting "Model|Contaminant Treatment Systems."
On the left side of the dialog box is a list of the contaminant treatment systems that have already been defined. When the dialog box is first displayed, no contaminant treatment systems will have been defined. A new system can be created by clicking the Add button. An existing system can be removed by selecting it in the list and clicking the Delete button. When a system is selected, it is possible to edit it in the remainder of the dialog box.
At the top of the dialog box is an edit box labeled System Name which is used to identify the particular system being edited but the system name is not actually part of the required input of the CTS package. Below that are three to five tabs.
All of the tabs contain tables of times and properties. Rows can be added to, inserted in, or deleted from the tables by changing the Number of times or by clicking the Add 
, Insert 
, or Delete 
buttons respectively.
The Wells tab is used to identify the the wells that are part of the contaminant treatment system in each time period. The tab contains a table in which the user defines the starting and ending times for when the wells in the system change and the names of the objects that define the extraction and injection wells for the time period. The names of the objects, separated by commas, are listed in the appropriate cells of the table. The user can click in a cell of the table and an Edit button and the Edit Selected Wells dialog box will appear in which the user can edit which well objects will be included in the extraction or injection wells.
The Treatment Level (ItRTINJ) is specified on the Treatments tab. There are three possible options: No treatment (0), All wells treated alike (1), or Each well treated individually (3).
If No treatment (0) is selected, no other information is required.
If All wells treated alike (1) is selected, all the wells will receive the same level of treatment. The treatments are specified in a table below the Treatment Level. The user must specify the starting and ending times for treatments, the Treatment option (IOPTINJ) and the associated value (CMCHGINJ) for each chemical species. The values can be specified using formulas based on global variables. The formulas can be edited with the Formula Editor. The Formula Editor is displayed by first selecting a cell in the table. A F() button will appear. Click the button to display the Formula Editor.
There are four treatment options.
Treatment Option (IOPTINJ) |
Explanation |
Percentage (1) |
percentage concentration/mass addition/removal is performed. Percentages must be specified as fractions. Example, if 50% concentration/mass removal is desired, -0.5 must be specified. |
Concentration change (2) |
concentration is added/removed from the blended concentration. Specified concentration CMCHGINJ is added to the blended concentration. If the specified concentration removal, CMCHGINJ, is greater than the blended concentration, the treated concentration is set to zero. |
Mass (3) |
mass is added/removed from the blended concentration. Specified mass CMCHGINJ is added to the blended concentration. If the specified mass removal, CMCHGINJ, is greater than the blended total mass, the treated concentration is set to zero. |
Specified concentration (4) |
specified concentration is set equal to the entered value CMCHGINJ. A positive value is expected for CMCHGINJ with this option. |
If Each well treated individually (3) is selected on the Treatments tab, the Individual Treatments tab will be present next to the Treatments tab. The Individual Treatments tab is similar to the Treatments tab except that on the left it has a list of well objects and at the top it has a Use default options checkbox. On this tab, you specify the treatments for individual wells by selecting a well from the list on the left. If the Use default options checkbox is checked for a well, the times and values from the Treatments tab will be used for that well. Otherwise the treatments to be used for the selected well must be entered in the table on the Individual Treatments tab. All the injection wells for the selected contaminant treatment system will be in the list but a well will only be used for a specific time period if it is included for that time period in both the Individual Treatments and the Wells tabs. The values can be edited with the Formula Editor as on the Treatments tab.
If there is flow into the contaminant treatment system from an external source or flow out of the system to an external sink, these flows along with the inflow concentrations are specified on the External Flows tab. If nothing is specified on this tab, the external flows will be zero. The first two columns in the table are used for specifying the starting and ending times. The other columns are for specifying the values of outflow, inflow, or inflow concentration. The values can be edited with the Formula Editor as on the Treatments tab.
The Max Allowed Concentration tab will be visible if IFORCE equals 0 on the CTS: Contaminant Treatment Systems pane of the MODFLOW Packages and Programs dialog box. On this tab, the user enters the maximum allowed concentration of each solute in the blended injection fluid. The injection water will only be treated if the concentration in the blended fluid exceeds the specified amount. If no values are specified on this tab, the maximum value will be set to zero.
