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• <br /> compounds, and because mass transfer of 03 into the aqueous phase and/or hydrocarbons <br /> into the gas phase is inefficient <br /> 1503 + C6H6 6CO2 + 1502 + 3H2O Eqn 1 <br /> benzene <br /> 1803 + C7118 7CO2 + 1802 + 41120 Eqn 2 <br /> toluene <br /> 2103 + CgHlo —> 8CO2 +2102 + 5H2O Eqn 3 <br /> ethylbenzene or <br /> xylene <br /> 1503 + CSH120 —> 5CO2 + 1502 + 61420 Eqn 4 <br /> MTBE <br /> Table 1. Ozone Stoichiometry <br /> Cam ound G Ozone 1 g hydrocarbon <br /> Benzene 92 <br /> Toluene 9 5 <br /> Ethylbenzene 9 5 <br /> Xylenes 9 5 <br /> MTBE 8 2 <br /> It is unknown whether Equations 1-4 also apply to oxidation by Peroxone, but the <br /> equations can be used to provide a first approximation of the amount of ozone needed to <br /> destroy the hydrocarbons The amount of H2O2 would be determined by the desired 03 to <br /> H2O2 ratio As with ozone alone, a greater-than-predicted dose would most likely be <br /> needed due to the reactions with TPH-g, TPH-d and non-target compounds <br /> Because ozone is a gas and H2O2 decomposes to form oxygen gas, in situ treatment via <br /> infection of peroxone into the sub-surface could result in removal of volatile compounds <br /> by sparging rather than oxidation Lab testing using inert nitrogen gas instead of ozone <br /> addressed whether hydrocarbon removal was due to destruction or volatilization <br /> 1.2 Potential Secondary Effects of Ozone and Peroxone <br /> Both ozone and Peroxone are non-selective oxidizing agents that may react with soil and <br /> groundwater components in addition to target compounds Treatment of water with <br /> ozone can produced disinfection by-products (DBPs) One DBP is bromate, which can <br /> be formed by oxidation of naturally occurring bromide Other potential effects of ozone <br /> and/or Peroxone use include oxidation of soil chromium to form water soluble Cr(VI), <br /> mobilization of metals such as manganese, oxidation of reduced nitrogen species to <br /> nitrate, and precipitation of dissolved iron The formation of Cr(VI) and bromate are of <br /> particular concern due to potential adverse effects on human health and the environment <br /> Mobilization of manganese can occur via oxidation of naturally occurring manganese <br /> compounds, such as manganese dioxide (Mn02), to permanganate (Mn04 ) Formation <br /> PRIMA Environmental 2 Eva]of Peroxone <br /> June 1,2005 ETIC-Exxon#3942 <br />