5. Plasma Reduction of VOCs in Soil Vapor Extraction
Current and past Support:Tetra Tech, Rf
Environmental Systems Inc., ERP TAMU


We are developing of a non-thermal plasma-based process for the destruction and removal of volatile organic compounds(VOC) pollutants emitted during i) the regeneration of activated carbon and ii) soil vapor extraction. This specific approach is based on high frequency surface-wave generated plasmas. It has the potential to overcome problems associated with current methods used for the disposal of benzene, chlorohydrocarbons and related pollutant compounds that do not comply with current and recently proposed federal and state air emission regulations. The most efficient thermal destruction techniques only destroy benzene to about 99.6 %. In initial laboratory experiments, we have already demonstrated destruction and removal efficiencies (DRE's) of >99.99997% for benzene using the proposed plasma technique. We are now carrying out laboratory investigations and related modeling of fundamental chemical processes essential to the characterization of the plasma augmented destruction of benzene and related organics which are amenable to both adsorption by activated carbon and for soil vapor extraction methods. Spectroscopic analysis of the molecular species(reactants, intermediates, and products), reaction rates, and thermodynamic data associated with elementary reactions will used for kinetic modeling and optimization of pollutant destruction. Analytical methods, including on-line GC-MS and FTIR, and other advanced spectroscopic techniques are being applied to define such processes at a molecular level. The lack of reliable electron-molecule cross-sections has proven a major stumbling block in enhancing the modeling of plasma-based pollution control technology. We are thus exploiting a new approach based on FTIR supersonic jet spectroscopy (described elsewhere on this site) and relevant theoretical treatment of that data for the determination of such electron-molecule cross-sections. Essential data for the quantitative characterization and modeling of the fundamental destruction processes will then be available for optimization of conditions that will facilitate design of prototype pollution control devices based on this technology. Such optimization will emphasize destruction and removal efficiencies (DRE's) of contaminants of concern and elimination of environmental pollutants during processing. We intend that the proposed investigations will lead to the development of a technology that will enhance or replace current incinerator and other thermal or chemical technologies used in the destruction of benzene and other related organics which are desorbed during the regeneration of activated carbon and soil vapor extraction.