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Environmental Protection Agency BIOCHLOR Overview  

BIOCHLOR is a natural attenuation screening model used to assess the feasibility of monitored natural attenuation (MNA) as a remedial approach for plumes of dissolved-phase chlorinated volatile organic compounds in groundwater. BIOCHLOR is built around the Domenico model, an analytical fate and transport model that simulates solute transport without decay or with sequential first-order decay in one or two reaction zones.


  • Analytical Modeling
  • Site Screening
  • Remedial Process Selection
  • Input
  • Tabular File: NA
  • Graphical File: NA
  • Output
    • Tabular File: NA
    • Graphical File: *xls
    • Print Report: Yes
    • Chlorinated Solvents
    • Groundwater
    Technical Team Members
    • Hydrogeologist
    • General technical staff familiar with chemical fate and transport
    BIOCHLOR - data loading
    • Used Microsoft Excel 2000 version of BIOCHLOR with Excel 2003, and it worked without error.
    • Data entry must be done manually. Data is entered into a Microsoft Excel spreadsheet.
    • Includes macros to aid in selecting coefficients.
    BIOCHLOR - graphic loading
    • Not applicable.
    BIOCHLOR - logical flow
    • The steps are numbered in the order the data must to be entered, with the exception of Step 7, Field Data. These data should be entered early to help in Step 4, selection of decay coefficient.
    • Help file displays graphic of spreadsheet; user clicks on section to go directly to that help file.
    BIOCHLOR - expert knowledge
    • Site-specific data should be used whenever possible to estimate model parameters so that the model is representative of potential site conditions. Although site-specific data are always preferred, "typical" ranges of many of the input parameters are provided in the manual. The selection of "typical" parameters should be reviewed by the appropriate expert (hydrogeologist, chemist, or environmental engineer).
    • Knowledge of biotransformation is useful when using this software. In Step 4, the user is allowed to adjust the decay coefficients to meet the comparison field data in Step 7. This step is not possible without knowledge of these processes.
    BIOCHLOR - functionality
    • Natural attenuation screening tool allows user to evaluate whether the site is suitable for monitored natural attenuation (MNA) before completing the entire spreadsheet. This software requires site-specific geochemical and field parameter data to be accurate.
    • Software provides a step-by-step process to enter field and chemistry data to develop graphs of concentration versus distance predicted by two methods (first-order decay function and instantaneous degradation model) against observed concentrations in wells along the centerline of the plume.
    • User can enter various simulation times to develop a time series. Animation can be used to show a succession of curves to illustrate how the plume will change over time.
    • Graphs that show concentration versus distance can be displayed in a 1-D graph (centerline) showing how the contamination moves in the x-direction or in a 3-D (array) that displays how the contamination moves in the x, y, and z directions.
    • User can display graphs for each contaminant individually or all of them on one graph. The predicted curves are graphically compared with field data the user enters. The user can interactively observe the effect of parameter values on the predicted curves by changing the values and viewing the graphs.
    • Target levels can be entered for each contaminant, and the graphs will display only the locations that exceed these values.
    • Software calculates plume mass depending on the size of the model area and the input parameters.
    • User can compare MNA with a pump-and-treat scenario for the site to evaluate whether MNA is the most cost-effective cleanup method.
    BIOCHLOR - documentation
    •Version 1.0 user manual and Version 2.2 user manual addendum are available online.
    • Manual discusses in detail the process of MNA and the Domenico analytical solute transport model.
    • Help menus are easy to access with a point and click, and they aid the user in identifying the type of data needed to use in the model.
    BIOCHLOR - output
    • Software provides limited output in the form of Microsoft Excel spreadsheets and graphs.
    • Various types of graphs are offered (1-D, 3-D) and can be animated to show how the contamination moves at the site over time.
    BIOCHLOR - sources
    • Version 2.2 downloaded November 15, 2004.
    • Help Menus.
    • User Manual.
    Note that this DST matrix is under active construction. Comments and suggestions about the structure
    or content of this website should be sent to Mike Adam .
    This web site contains technology information from private contractors and government agencies and is for informational purposes only. EPA cannot guarantee the accuracy or completeness of the data. Reference to any specific commercial product, process, or service, by trade name, trademark, manufacturer, or otherwise, does not constitute or imply the endorsement, recommendation, or favor of the United States Government.