1

 0.9 RW
 o MLS
 0. Langmuir Fit
 0.8
 0 0
 0.7 0


 0.6 */
 0.5 -

 LL 0.4

 0.3 -

 0.2 <



 0
 0 0.5 1 1.5 2 2.5 3

 % PCE Saturation (Pre-Flood PITT)



Figure 2-15. Fractional NAPL removal (FNR) as a function of initial PCE saturation from the

 1998 ethanol flood at the Sages site.

 PCE can be adsorbed to aquifer media, but much more was likely present as a separate

phase that was held tightly by capillary forces. Since the goal of this remedial effort was

enhancing solubility, the IFT of PCE and water was not intentionally reduced to limit PCE

mobilization. Without a significant decrease in IFT, entrapped residual PCE bound by capillary

forces cannot be overcome and some residual PCE will remain. The process becomes diffusion

limited. Thus lower saturation zones exhibited lower FNR at Sages.

 Although FNR in Figure 2-15 and estimated fluid velocity in Figure 2-5 both separately

demonstrated correlations to initial PCE saturation at the Sages site, these two parameters were

not correlated.