BIOSCREEN-AT

Version 1.42 with exact analytical solution

BIOSCREEN-AT is a screening-level model developed for and distributed by the U.S. Environmental Protection Agency (EPA)[1] that simulates remediation through natural attenuation of dissolved hydrocarbons at petroleum fuel release sites. BIOSCREEN is also routinely used for simulating the movement of a wide variety of dissolved solutes in groundwater. The software, programmed in the Microsoft ExcelTM spreadsheet environment, uses the Domenico analytical solute transport model for solute transport in three-dimensional porous media. The Domenico model has the ability to simulate advection, dispersion, adsorption, and aerobic decay as well as anaerobic reactions that have been shown to be the dominant biodegradation processes at many petroleum release sites. BIOSCREEN Version 1.4. BIOSCREEN as distributed by the EPA, only provides this Domenico analytical solution to the solute transport equation. This analytical solution is an approximate solution to the solute transport equation that, under some circumstances, produces solutions that differ significantly from the exact solution to the solute transport equation.[2]

BIOSCREEN-AT is an enhancement of the standard BIOSCREEN program. In BIOSCREEN-AT a second, solution method has been implemented that can be chosen by the user as an alternative to the Domenico solution. The alternative method is an exact three-dimensional analytical solution for solute transport from a patch boundary condition within a semi-infinite aquifer[3]. This solution, unlike the Domenico solution, is exact and with the use of this method the user does not introduce numerical error of unknown magnitude into the solution. The Excel user interface for BIOSCREEN-AT is nearly identical to that for BIOSCREEN and a user familiar with BIOSCREEN will have no difficulty using BIOSCREEN-AT. With BIOSCREEN-AT it is possible to easily quantify the error introduced by the Domenico solution, and to present results calculated using either – or both – solution methods.

BIOSCREEN-AT is available for download FREE from this web page. The authors, M. Karanovic and C. Neville, request only that application of the software and production of results using the code is accompanied by a suitable acknowledgment. The software is provided "AS IS", without warranty of any kind, including without limitation the warranties of merchantability, fitness for a particular purpose and non-infringement. The entire risk and responsibility as to the quality and performance of the Software is borne by the user. The author(s) disclaim all other warranties.

[1] Newell, C., R. McLeod and J. Gonzales, 1996. BIOSCREEN, Natural Attenuation Decision Support System, User’s Manual Version 1.3. EPA/600/R-96-087. This document is available on the U.S. EPA web site at  http://www.epa.gov/ada/csmos/models/bioscrn.html.

[2] For a detailed discussion of the approximate nature of the Domenico solution and the error introduced by the use of the equation refer to Guyonnet, D. and C. Neville, 2004, Dimensionless analysis of two analytical solution for 3-D solute transport in groundwater, Journal of Contaminant Hydrology, 75:141-153.

[3] This solution was developed by C. Neville and is called ATRANS. Documentation of the solution with validation is contained in the compressed archive file downloaded from this page.

Please direct all inquiries about any SSP&A software to  models@sspa.com