Numerical and Experimental Investigation on the Mobilization of Residual NAPL by Seismic Waves

Applying seismic waves might improve the efficiency of conventional pump-and-treat technologies for cleaning up aquifers contaminated by nonaqueous phase liquids (NAPL). We investigate the hypothesis that the mobilization of trapped NAPL blobs can be enhanced by exploiting capillary-induced resonance. We have developed a theory that allows us to estimate the response of a trapped NAPL blob to variable frequency excitation including its resonant frequency. Physical experiments to image the response of blobs to seismic waves in single pore channels and sphere packings at a high spatial and temporal resolution are under way. To obtain an unobstructed view of the blobs we match the optical refraction indices of the liquids and the solid phase and illuminate the porous medium with a laser light sheet. Finally, 3D Lattice-Boltzmann simulations will be used to demonstrate that a trapped NAPL blob in a porous medium exhibits resonance.