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1 MTBE removal data is presented in Table 4 A summary of the emissions data is presented in Table 5 SVE well data, including open/closed status, vacuum, flow, and PID data are presented in Table 6 Graphical presentation of TPHg and benzene mass removal and influent concentration data are ' shown on Figures 6 and 7, respectively Copies of the O&M field notes are included in Appendix A Influent and effluent vapor sample laboratory analytical reports are included in Appendix B As shown in Figure 6, the SVE system influent contaminant concentrations demonstrated a sharp increase in concentrations coincident to the startup of the 300-sefm SVE skid on June 26, 2003 The ' 300-scfin SVE skid pulls higher vacuums and greater flow rates than the previous 500 scfin SVE skid with thermal oxidizer The increased vacuum and flow resulted in an initial increase in influent contaminant concentrations After July 23, 2003 the vapor influent concentrations sharply decreased from 790 ppmv and leveled off to an average of 266 ppmv in September through October 2003 The mass removal trend (Figure 7)demonstrates that mass removal is on a steady low angle incline 33.2 Ozone Sparge System ' A skid-mounted ozone sparge system, enclosed in a shed within the remediation compound, can inject ozone into groundwater through 19 available ozone sparge wells (S-1 through S-19) located on- and offsite Sparge well S-20 was not connected to the sparge system manifold and is not used tAn ozone meter attached to the ozone sparge system skid will shut down the remediation system if ozone is detected at levels greater than 0 01 ppm within the shed The ozone injection manifold is set up to inject ozone for 10 minutes at a time into the sparge wells It can cycle through 10 wells at 100% the maximum injection rate (one well at a time), or all 20 wells (two wells at a time) at 50% the maximum injection rate Approximately 2 5 pounds of ozone can be injected into the subsurface ' each day at optimum ozone production Ozone production is variable dependent on atmospheric temperatures The ozone sparge system is designed to deliver at an approximate rate of 6 liters per t1linUte On May 27, 2003, it was observed that there was no flow registering on the ozone generator flow ' meter Motsture was observed in the ozone line leading from the ozone generator to the manifold It was also observed that the pressure relief valve in the oxygen condenser was relieving frequently ' Geocon consulted with ARCE Systems, Inc , the ozone system skid assembler, to correct the system ARCE indicated that the ozone generator would need maintenance that could only be performed at their shop and the oxygen condenser would have to be re-packed by the manufacturer On May 30, 2003, the ozone generator and oxygen condenser were removed and transported to ARCE in Massachusetts The re-furbished ozone generator was returned in August 2003 and was re-installed ' on August 6, 2003 However, the ozone sparge system could not be operated without the oxygen condenser ARCE indicated that the manufacturer of the oxygen condenser had not re-packed the condenser at that point in time Due to the delays in the return of the oxygen condenser and the lack ' of confidence in that manufacturer's product, ARCE and Geocon concluded that ARCE's new re- engineered oxygen condenser unit would be necessary for the ozone sparge system Pi ILU No S8643-06-o t -6- N0VC111bCr 3,2003 1