Publication Date

5-2011

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Civil Engineering

Department

Civil Engineering

Major Advisor

Arvin Farid, Ph.D.

Abstract

The task of cleaning soil and/or groundwater contaminated by leakage from aging underground gasoline or petrochemical tanks along with surface spills of gasoline and other hazardous chemicals is of utmost importance for federal and state environmental agencies. Traditional clean up and contaminant removal involves dig-and-treat methods that are costly and impractical for large, contaminated sites. Less disruptive remediation techniques, such as air sparging, have become more attractive in the past decade. Air sparging, bioventing, and other remediation technologies that use air injection into soil can become very effective for non-aqueous phase liquid (NAPL) removal using volatilization and bioremediation. However, the effectiveness of methods such as air sparging is limited by the restriction of airflow. The majority of the injected air in air sparging flows through narrow air channels formed in the soil and water matrix, which forms a limited mass transfer zone (MTZ) for contaminant removal. Diffusion of air between these air channels, even though very slow, can help the cleanup. Pulsation of the air sparging pumps is among the only existing methods used to enhance airflow, but it is time-consuming and unable to create a controlled and uniform airflow pattern.

In this thesis, use of electromagnetic (EM) stimulation to expedite air sparging is investigated. A relatively high-power electromagnetic field is radiated into the water by utilizing a co-axial antenna connected to an EM source. The alternating electric field emitted into the medium can stimulate different mechanisms in the medium. As a result, the stimulated water molecules enhance diffusion of air and contaminant. This thesis shows the first step in the study of EM stimulation on air and contaminant flow through saturated soils via an analogous demonstration of the effect of EM waves on diffusion of a non-reactive dye in water. It is successfully demonstrated in this work that the EM stimulation of the water and dye controls and changes the direction and rates of dye transport. The relation between the EM power input radiated into the medium and the change in the transport of the dye is also studied.

Share

COinS