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1 <br /> 3.4 RESULTS AND DISCUSSION <br /> Significant amounts of each COC were removed from the aqueous phase within 1 hour <br /> when sparging with nitrogen or ozone However, removal by ozone was via destruction, <br />' while removal by nitrogen was via volatilization Complete removal was achieved by <br /> 6 25 hours Treatment with ozone increased the aqueous concentrations of bromate, <br /> Cr(VI), and nitrate Cr(VI) was reduced by soil that had not been exposed to ozone <br /> 3.1 COC Removal <br />' The aqueous concentrations of CDCs are shown in Table 3 Off-gas concentrations are <br /> shown in Table 4 The "Percent Volatilized" was calculated according to <br />' Percent Volatilized in First Hour = <br /> 100 x [(CO-30Vo-30)+ (C30-60V30-60)I/Caq,t=OVaq,t=O <br />' where <br /> CO-30 = the concentration (µg/L) in the off-gases collected from 0 to 30 minutes, <br /> V0_30 =the volume (L) 1n the off-gases collected from 0 to 30 minutes, <br />' C30-60 =the concentration (4g/L) in the off-gases collected from 30 to 60 minutes, <br /> V30_60 =the volume (L) in the off-gases collected from 30 to 60 minutes, <br /> Caq i,-o =the concentration (4g/L) in the aqueous phase at Time = 0 minutes, <br />' Vaq,r=a=the volume (L) of the aqueous phase at Time =0 minutes <br />' Both nitrogen sparging and ozone sparging completely removed all TPH-g and BTEX <br /> from the aqueous phase within 6 25 hours However, removal was due to volatilization <br /> in the Nitrogen test, but was due to destruction in the Ozone test-44-96% of CDCs were <br />' in the off-gases from the first 60 minutes in the nitrogen test, but only 0 6-3% were seen <br /> in off-gases from the Ozone test <br /> Neither TBA nor MTBE was detected in any case Small amounts (19-34 4g/L) of <br /> acetone were detected in the Nitrogen test, while larger quantities (390-450 gg/L) were <br /> detected in the Ozone test The presence of comparatively large quantities of acetone in <br /> the ozone test confirmed that CDCs losses in the ozone test were due to destruction, <br /> because acetone is a potential intermediate of petroleum hydrocarbon oxidation The <br /> concentration of acetone decreased in the ozone test, indicating that it, too, can be <br /> removed given sufficient time <br /> 3.2 Secondary Water Quality Parameters <br /> IThe effect of treatment on secondary water quality parameters is illustrated in Table 5 <br /> Data for Untreated GW and soil are included for comparison The % Change was made <br /> relative to conditions at Time 0, unless measurements were not made at Time 0 Then, <br /> comparisons were made relative to the Control <br /> PRIMA Environmental 7 Eva[of Ozone <br /> January 27 2005 ENSR-Unocal 5098 <br />