Horizontal and vertical well comparison for in situ air sparging

A laboratory study was conducted to determine the effectiveness of vertical and horizontal well configurations for ground water remediation using in situ air sparging. A lexan tank was designed and constructed to allow both the visualization of air flow and quantitative measurement of the distribution of air flow. Two media, sand and glass beads, were tested with both vertical and horizontal air sources. In each case, most of the air traveled through preferential channels as continuous flow rather than as discrete bubbles as reported in other studies. Even though glass beads were selected to have the same grain-size distribution as the sand, air flow was quite different through the two media. Results show that glass beads are not a suitable material for modeling air flow through natural sediments. In this study, the horizontal well proved to be more effective than the vertical well by impacting more of the media with a uniform distribution of air through-out the media. The vertical well resulted in a nonuniform distribution of air flow with most of the air concentrated directly above the well.