Practical Modeling of SVE Performance at a Jet-Fuel Spill Site

A coupled flow and transport model (VENT3D) was used to simulate the performance of soil vapor extraction at a jet-fuel (JP-4) contaminated site. The contaminant mixture was approximated with 10 surrogate components categorized by carbon number class. The contaminant was distributed heterogeneously throughout the soil. The initial total contaminant mass was the only parameter that was adjusted, and it was fit to the observed removal during the pilot tests. The predicted total mass removal using the most general approach matched the observed hydrocarbon mass removal within ±4%. The effects of the following selected simplifying assumptions were examined with the model: (1) uniform contaminant distribution; (2) 2D horizontal flow; and (3) single equivalent contaminant. The uniform soil contamination distribution and the horizontal flow assumptions yielded similar results-both estimated removal rates that were initially higher by 30% and eventually overpredicted the total removal by 10%. The equivalent single-component approximation underpredicted the removal by as much as 50% during the first half of the operation and then overpredicted the removal, ultimately overpredicting the total removal by <10%.