This study investigates the effect of frequency from sonic energy coupled with soil fracturing for the removal of volatile organic compounds from low permeability soils. The laboratory experiments consisted of a test cell, 12 1/2 inches by 12 1/2 inches and 23 3/4 inches high, containing a 1/2 inch geotextile made to simulate the fracture. The pneumatic sound generator used was a siren type generator designed and built at NJIT.

Laboratory experiments were performed using the NJJT siren at frequencies of 2957, 6637, 10317, 13997 Hertz and baseline tests with no sound energy were also conducted. The free moisture content was measured by weight loss over time and the concentration of the contaminant was measured by using gas chromatography with a Flame ionization Detector. These measurements were monitored frequently throughout the experiments. The results of this study at different frequencies were analyzed and correlated and were also compared with the results obtained by Fernandez (1997) using the NJIT siren and the whistle. The measurements agreed with those of Fernandez and showed a slight increase in the removal rate constant with a rise in frequency but this improvement was not significant.

It was concluded that within the range of frequencies studied, no significant improvement in removal rate can be attributed to frequency. It is recommended that the siren should be reconfigured to operate at higher frequencies (20 kHz) and much higher sound intensities (> 145 dB).