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1 - <br /> EIV�yt <br /> Margaret Lagorio <br /> February 17, 2004 <br /> Page 3 <br /> ' Ozone Microsparge System Operation <br /> The schedule was initially set to cycle through each point 18 times per day, for nine minutes per <br /> point per cycle. There is an eight-minute rest period between cycles. The programmable <br /> timer/controllers are varied during the quarter to provide more treatment to selected areas. <br /> ' Ozone Micros ar e S stem Status <br /> System effectiveness is monitored by assessing groundwater analytical data and concentrations <br /> ' of dissolved oxygen (D.O.) from single-completion wells U-3 and U-10 and nested piezometers <br /> NP-1 and NP-2 (Figure 2). Wells U-3, U-10 and NP-1, NP-2 are within the zone of influence of <br /> one or more sparge points. D.O. readings are collected monthly from wells U-3, U-10, and <br /> ' piezometers NP-1 and NP-2. A summary of D.O. concentration data is presented in Table 4. <br /> Well construction details and D.O. readings are summarized in Tables 7 and 8, respectively. <br /> Concentrations of TPH as gasoline and benzene in wells U-3 and U-10 and piezometers NP-1 <br /> and NP-2 are depicted graphically in Attachment D. The ozone micro sparge system was <br /> operated only intermittently during the Fourth Quarter 2003 due to equipment malfunctions and <br /> power outages. <br /> Effectiveness of Ozone Microsparge System <br /> Groundwater samples were submitted for analyses of BTEX by EPA Method 8021, TPH as <br /> gasoline by EPA Method 8015 Modified, and fuel oxygenate compounds: MTBE, TAME, TBA, <br /> DIPE, and ETBE using EPA Method 8260B. Copies of the groundwater sampling information <br /> sheets are included in Attachment B. Laboratory analytical results with chain-of-custody <br /> documentation are included in Attachment C. Concentrations of TPH as gasoline and benzene <br /> vs. time in wells U-3 and U-10 and piezometers NP-1 and NP-2 are depicted graphically in <br /> ' Attachment D. <br /> TPH as gasoline Concentration Trends <br /> • Concentrations of TPH-g have decreased in piezometers NP-1-65, NP-2-6 since August <br /> 2003. <br /> • Concentrations of TPH-g in wells U-3, U-10, NP-1-22, NP-2-6 have increased since August <br /> 2003. <br /> ' Benzene Concentration Trends <br /> • Concentrations of benzene have decreased in piezometers NP-1-65, NP-2-60 since August <br /> 2003. <br /> • Concentrations of benzene in well U-3, and piezometer NP-1-22 have increased since <br /> August 2003. <br /> J:1Projects1069401325-01871FinallReportsl4th Qtr 2003-QMR RSR.doc <br /> ' 35 Years of Excellence in Environmental Services <br />