Monitoring the Removal of Immiscible Contaminants from Sandy Soils by Dielectric Measurements

RINALDI, VICTOR A; FRANCISCA, FRANCO MATÍAS

JOURNAL OF ENVIRONMENTAL ENGINEERING

American Society of Civil Engineers (ASCE)

Lugar: Reston, Virginia, USA; Año: 2006 vol. 132 p. 931 - 939

0733-9372

The main objective of this paper is to explore the potential application of electromagnetic waves to evaluate the effect of contaminant removal in granular soils. Thus, various specimens of saturated silica sand were prepared using paraffin oil and lubricant oil as contaminants. Four flushing fluids were used to remove the contaminants from sand columns: Deionized water, water-detergent, water-detergent-alcohol solution, and water vapor. Dielectric permittivity was measured at different stages of the removal process at the frequency from 20 MHz to 1.3 GHz. The measured permittivity was compared with that determined for clean and fully contaminated specimens. A theoretical mixture formula was calibrated and implemented to estimate the volume fraction of contaminant present in the pore fluid. It is concluded in this work that dielectric parameters reflect the contamination level of the soil for the nonpolar organic compounds used here. Measurement of permittivity allows us to determine that the inclusion of alcohol and detergent in the displacing fluid improved the removal efficiency. However, water vapor was the most efficient removal agent.