Advanced Mixed Oxidation and Inclusion Technology

Coal tar contaminants, such as polycyclic aromatic hydrocarbons (PAH) currently are difficult to treat in a timely and cost-efficient manner. The generally poor performance of conventional PAH treatment schemes, such as soil flushing or bioremediation, has led to research application of innovative in situ remediation methods. This project focuses on the in situ destruction of recalcitrant coal tar PAH in soil and groundwater. Enchem Engineering, Inc. has an  innovative treatment approach based on simultaneous:  (1) desorption from soil or sediment; and (2) oxidation via radical formation. A proprietary reactive agent (OxyZone-C®) developed by Enchem’s team combines highly effective cyclodextrin-facilitated PAH desorption with the targeted delivery of a combination of powerful oxidants (ozone, buffered sodium persulfate, and hydrogen peroxide) in the treatment zone. The specific objectives of this study are to evaluate:  (1) the parameters (such as reagent concentration and contact times) that have the greatest effect on enhanced ozone solubility and stability in the presence of cyclodextrin; (2) the parameters that have the greatest effect on PAH degradation with respect to oxidation rate with ozone alone, ozone combined with hydrogen peroxide, and ozone, hydrogen peroxide, and persulfate, either buffered on un-buffered, of select target PAH compounds and mixtures leading to mineralization; (3) the parameters that have the greatest effect on desorption rate of select target PAH compounds and mixtures such as cyclodextrin type and concentration; and (4) the fate of cyclodextrin in the presence of the proposed oxidants and vice versa. The anticipated results of this study will provide an understanding of these objectives using batch and semi-batch experiments followed by column experiments to generate quantitative data needed to assess the performance of Enchem’s treatment technology under a variety of test conditions, including varying PAH concentrations. The demand for this technology as a method of PAH soil remediation is rated in billions of dollars for manufactured gas plant sites owned by the utility industry. There are many other types of sites that require remediation of PAHs such as fuel oils, jet fuels, and others at military bases and other Department of Defense and Department of Energy installations as well as National Priority List sites. Enchem also expects that this technology will prove useful for remediation of chlorinated organic sites containing dense nonaqueous phase liquids (DNAPLs) and for polychlorinated biphenyl (PCB) sites.