Formatted Title
Enhancing Remediation in Low Permeability Soils
Background/Objectives
Challenges of remediation in low permeability soils includes limitations to injecting and extracting liquids and/or gases to facilitate the treatment or recovery of organic compounds. For many legacy contaminated sites, there can be decades or more between when the contamination occurred and when efforts are undertaken to remediate the site. While migration of contaminants into low permeability soils is slow, the delays between when the contamination occurs and when remediation is undertaken provides ample opportunity for the low permeability soils to become contaminated. Remediation efforts generally attempt to recover or treat the contaminants in much less time. Lower groundwater flow rates in low permeability soils means that the contaminants are not flushed out of there rapidly. While the low permeability limits liquid flow in these soils, they can readily be heated.
Approach/Activities
Field experience with thermal remediation in low permeability soils will be the basis for this presentation, with supporting information coming from pertinent laboratory experiments.
Results/Lessons Learned
The thermal remediation technologies of electrical resistance heating (ERH) and thermal conductive heating (TCH) have been found to be very effective for heating low permeability soils. As the temperature increases, so does the mobility of volatile organic contaminants. Laboratory and field experience has shown that thermal remediation can effectively recover volatile contaminants from low permeability soils. The choice of thermal technologies and the design of the remedial system is critical for success. The above ground treatment system must also be designed to handle the fine sediments that are recovered during the remediation. This presentation will discuss the effects of increasing the temperature on the recoverability of contaminants.