CARBON DIOXIDE IN REMEDIATION OF CONTAMINATED SITES: PRELIMINARY RESULTS

SIAD S.p.A in collaboration with the Industrial Engineering Department of Bergamo University carried out, during 2011, a research about the use of carbon dioxide in remediation of contaminated sites. The research target was to evaluate the affinity of carbon dioxide with the contaminants of soil, in order to use it as carrier to remove the pollutant from soil. Data processing show that, in particular condition of flux and contact time, carbon dioxide demonstrates a PAH removal higher by 20-35% than nitrogen for Pyrene and Anthracene. Furthermore CO2 expresses on these two contaminants a carrier effect, able to move contamination from the deeper to the upper layer of the contaminated matrix. Tests under pressure show as liquefied CO2 enhances by more than one order of magnitude the extraction of PAHs and halogenated compounds compared with gaseous CO2. On the basis of such encouraging results, research is going on testing CO2 in a larger scale.