Formatted Title
The Science Behind Low Temperature Thermal Remediation
Background/Objectives
Over the 30 years and more since thermal remediation technologies were developed and commercialized, considerable interest in low using low temperature (approximately 40 - 60C) has been expressed with the thought that lower energy usage would make the remediation more ‘sustainable’. The interest has led to considerable research over the years, and a variety of field applications of low temperature thermal remediation. The objectives of these low temperature remediations have varied from enhancing biodegradation, promoting chemical reactions such as hydrolysis, or enhancing back diffusion from low permeability soils. Potential advantages cited of using lower temperatures include less energy usage, less potential to damage other infrastructure, and elimination of the need for an extraction system and above ground treatment of contaminants.
Approach/Activities
This presentation will look at the temperature dependencies of the properties that are being exploited when implementing low temperature thermal remediation (biological and chemical reactions), and compare those to the temperature dependence of the properties that are exploited at higher temperatures (vapor pressure, solubility, viscosity, and Henry’s constant). The differences in these properties at different temperature ranges will be discussed in detail to develop an understanding of what to expect when implementing low temperature thermal remediation as opposed to the more conventional higher temperature thermal remediation.
Results/Lessons Learned
All of the physical properties of organic compounds that control their migration in the subsurface are temperature dependent. As the temperature increases, the properties change in a manner that make these compounds more mobile in porous media. Many of the properties of organic compounds that are exploited for thermal remediation are not just sensitive to temperature, but they are exponentially related to temperature. Thus increasing the temperature improves our ability to recover these compounds. Temperature increases can also increase the rate of biological and chemical reactions, but these rates are not as sensitive to temperature as other physical properties. This presentation will explore the effects of different temperature ranges on the remediation of organic compounds.