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Footprint (A Screening Model for Estimating the Area of a Plume Produced from Gasoline Containing Ethanol
Citation:
Ahsanuzzaman, N., J. T. WILSON, M. Wang, AND R. C. Earle. Footprint (A Screening Model for Estimating the Area of a Plume Produced from Gasoline Containing Ethanol. EPA/600/R-08/058, 2008.
Impact/Purpose:
A model to estimate the length and surface area of BTEX plumes in ground water produced from a spill of gasoline that contains ethanol.
Description:
FOOTPRINT is a simple and user-friendly screening model to estimate the length and surface area of BTEX plumes in ground water produced from a spill of gasoline that contains ethanol. Ethanol has a potential negative impact on the natural biodegradation of BTEX compounds in ground water. The primary objective of the software is to predict the increase in surface area of the plume of BTEX compounds or any other chemical of concern (COC) due to the presence of ethanol in ground water. FOOTPRINT estimates the area of a plume of particular BTEX compounds that are contained within two biodegradation zones: 1) a zone that is immediately adjacent to the source, where ethanol is present in high concentration and no biodegradation of the BTEX compounds (or other COC) is allowed, and 2) a second zone, where the ethanol concentration is negligible due to natural biodegradation of ethanol in the first zone and biodegradation of the BTEX compound (or other COC) is contributes to attenuation in concentration of the BTEX compounds. FOOTPRINT is based on the modified version of the Domenico (1987) model published by Martin-Hayden and Robbins (1997). This model is an approximate analytical solution of the advective-dispersive solute transport equation with first-order decay. The model of Martin-Hayden and Robbins (1997) was further modified in FOOTPRINT to allow zero-order decay as well (see Appendix B of the user’s manual for details). As a result, FOOTPRINT can independently describe the natural biodegradation of ethanol and or the BTEX compound with either a zero order rate constant or a first order constant. FOOTPRINT can also estimate surface area of a plume or the concentration of the BTEX compound or COC at any given point down-gradient from the source for any COC decaying at a constant rate (First or Zero order) in the absence of ethanol.