The Effect of Electromagnetic Waves on Airflow During Air Sparging

Air sparging is a popular remediation technology used for treating soil and groundwater contaminated with volatile organic compounds (VOCs). Little is known about the system variables and mass-transfer mechanisms in the air-sparging process. The VOC removal process during air sparging is very slow and time consuming (it might take months or years). The hypothesis of this work is that electromagnetic (EM) waves can be used to enhance air sparging with minimal heat generation. The goal of this research is to study the effect of EM waves on air-channel formation and air diffusion between air channels within soil. This should ultimately help to create a technology to improve airflow and expedite the cleanup process using air sparing. This research presents the theoretical and experimental study to investigate the injected airflow pattern within a glass-bead medium used as an analogous medium to soil. The full three-dimensional (3D) vector electric field was needed for this study. Therefore, experimental measurements of the electric-field component of EM waves were performed, and the results were used to validate a numerical (finite element) simulation using COMSOL Multiphysics software. Air-sparging experiments were also performed at different injected air pressures, and digital images of the airflow patterns were collected. The size and shape of the zone of influence (ZOI) of airflow were measured. Airflow patterns were monitored for the unstimulated case as well as cases stimulated at various EM power levels and frequencies. The airflow was also modeled using a finite-difference method. A coupled analysis of airflow and EM-wave propagation was used to evaluate the correlation between EM-wave characteristics and air sparging.