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BIOCHLOR, Natural Attenuation Decision Support System

BIOCHLOR is a screening model that simulates remediation by natural attenuation of dissolved solvents at chlorinated solvent release sites. BIOCHLOR includes three different model types:

  • Solute transport without decay
  • Solute transport with biotransformation modeled as a sequential first-order decay process
  • Solute transport with biotransformation modeled as a sequential first-order decay process with two different reaction zones (i.e., each zone has a different set of rate coefficient values)

The software, programmed in the Microsoft Excel spreadsheet environment and based on the Domenico analytical solute transport model, has the ability to simulate one-dimensional advection, three-dimensional dispersion, linear adsorption, and biotransformation via reductive dechlorination (the dominant biotransformation process at most chlorinated solvent sites). Reductive dechlorination is assumed to occur under anaerobic conditions and dissolved solvent degradation is assumed to follow a sequential first-order decay process.

EPA is no longer updating BIOCHLOR. While this tool is still publicly available, technical support from our researchers may be limited.

BIOCHLOR Version 2.2

BIOCHLOR Version 2.2 includes the following new features: rate constant decision support, source decay, and animation. A rate constant decision support feature was incorporated to help users estimate rate constants required for model calibration. In addition to simulating a source of constant concentration, BIOCHLOR Version 2.2 models a decaying source, which allows the simulation of both plume expansion and contraction. Lastly, an animation feature has been incorporated, which permits the visualization of plume behavior. This document describes these new features. Users should continue to refer to the existing BIOCHLOR Version 1.0 User’s Manual (Aziz et al., 2000a) as the primary source of information about BIOCHLOR.

Specifications

Version 2.2
Release Date June 2002
Development Status General Release
Operating System Windows 95/98/NT, Excel

Minimum System Requirements

The BIOCHLOR model requires a computer system capable of running Microsoft Excel 97 or 2000 for Windows. Operation requires an IBM-compatible PC equipped with a Pentium II or later processor. A minimum of 64 MB of RAM is strongly recommended.

Downloads

Excel 2000 Version: User's manual, installation program, help files, and installation instructions (exe) (2.28 MB)

Excel 97 Version: User's manual, installation program, help files, and installation instructions (exe) (2.21 MB) Excel 97 Version: User's manual, installation program, help files, and installation instructions (EXE)

US EPA. (2000) "BIOCHLOR, Natural Attenuation Decision Support System - User's Manual, Version 1.0." (PDF) (54 pp, 541 K, About PDF)

US EPA. (2002) "BIOCHLOR, Natural Attenuation Decision Support System, Version 2.2, User's Manual Addendum." (PDF)

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Last updated on April 21, 2025
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