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<br /> r � Mr. James L.L. Barton d
<br /> July 5, 2005
<br /> Page 2 of 5
<br /> witnessed by Regional Board and EHD staff. Bi-weekly sampling program established pursuant to Regional
<br /> Board requirement.
<br /> July 26,2004: Treatment system down due to extraction pump failure. Approximately 324,342 gallons of
<br /> water treated through carbon units since December 2003 changout of Cl; approximately 55.3 pounds of
<br /> TPHg, 20.2 pounds of BTEX, and 19.7 pounds of MTBE were removed from the groundwater during that
<br /> time using the carbon units (no air stripper) with no breakthrough in Cl. Treatment system was idle
<br /> between July 26, 2004 and August 24, 2004, except for limited testing of air stripper after installation.
<br /> Table 2 summarizes the mass of contaminants removed from the dissolved contaminant plume, based upon
<br /> influent concentrations and the volume of extracted groundwater.
<br /> August 24, 2004: Treatment system re-started after air stripper installed in flow stream before carbon units.
<br /> Initial concentration of post air stripper sample (ASI)was 70.9 ppb total VOCs, including 3.3 ppb MTBE.
<br /> Table 3 summarizes analytical results of treatment system samples.
<br /> October 26, 2004: Breakthrough of MTBE in C1 (4.5 ppb); sample from ASI contained 2.8 ppb MTBE.
<br /> Extraction continued with treatment via air stripper followed by C1 (breakthrough), C2, then 200-pound
<br /> carbon polish. No VOCs or MTBE in effluent sample.
<br /> December 16, 2004: Carbon unit C1 replaced with virgin carbon. Unit offline between December 15 and
<br /> December 21. Between July 26 and December 21, 2004, approximately 181,817 gallons of extracted water
<br /> were treated. Approximately 16.0 pounds of TPHg, 5.6 pounds of BTEX, and 1.3 pounds of MTBE were
<br /> removed from the groundwater during that period. However,the estimated load on carbon unit C2 was only
<br /> 0.9 pounds, since breakthrough of C I was not documented until October 26, 2004.
<br /> December 21, 2004: Both carbon units brought back on line with C2 as lead unit and Cl as trail unit. The
<br /> air stripper was not operational due to scaling in the stripper effluent feed pump.
<br /> January 18, 2004: Replaced the effluent pump on the air stripper and re-started air stripper. Between
<br /> December 21, 2004 and January 18, 2005, approximately 52,309 gallons of water were treated, with 1.1
<br /> pounds of TPHg, 0.4 pounds of BTEX, and 0.3 pounds of MTBE removed.
<br /> January 24, 2005: Treatment system samples collected; AS 1 contained MTBE at 140 ppb, no breakthrough
<br /> in lead carbon unit C2, no load on carbon unit Cl.
<br /> February 24, 2005: Scaling noted in carbon unit C2 greatly restricting flow; carbon unit C2 temporarily
<br /> taken offline for acid wash pursuant to recommendations by contractor and carbon supplier. Between
<br /> January 18 and February 24, 2005, approximately 101,171 gallons of extracted water were treated.
<br /> Approximately 2.8 pounds of TPHg, 1.2 pounds of BTEX, and 0.7 pounds of MTBE were removed from
<br /> the groundwater during that period. However, the load on carbon unit C1 was essentially zero, since there
<br /> was no breakthrough in C2.
<br /> March 8, 2005: Conducted acid wash of carbon unit C2. Between February 24 and March 8, 2005,
<br /> approximately 55,188 gallons of extracted water were treated. Approximately 1.6 pounds of TPHg, 0.7
<br /> pounds of BTEX, and 0.4 pounds of MTBE were removed from the groundwater during that period.
<br /> However, the estimated load on carbon unit Cl during that period, based upon 82% air stripper efficiency
<br /> suggested by the recent analytical results,was only 0.5 pounds.
<br /> March 18, 2005: Lead carbon unit C2 bypassed again due to scaling. Between March 8 and March 18,
<br />
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