SITE INFORMATION AND CORRESPONDENCE FILE 3

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CAMBRIA stream. We believed that, if granted an NPDES permit, we could continue to operate the existing GWE and treatment system without any redesign. As part of the permit application we needed to get permission to discharge into the storm drain from the municipality that operates the storm drain. MUD operates the storm drain in the vicinity of the site. We contacted MUD staff about possible discharge of treated groundwater into their storm drain. MUD considered this and eventually decided not to allow us to discharge, which meant that we would not able to obtain an NPDES permit. © Treatment of TBA with Carbon Of the seven fuel oxygenates, TBA is the most difficult to treat with carbon. We consulted Shell' s technical experts in Houston to assess the current treatment systems ability to treat TBA per the MUD discharge permit requirements. The results of this assessment were that the current treatment system is able to treat TBA with the following conditions. The first condition is that we would have to increase the carbon changeout frequency at this site as TBA would likely move through the carbon vessels faster than any other fuel oxygenate. The second condition is that reconfiguring the carbon vessels so that water flow up through the vessel rather than down through the vessel would yield a longer carbon life. At this point we decided to restart the GWE system. Prior to shutting down the system the carbon had been changed out. So we decided to use up this fresh carbon, and during the next carbon change out we would reconfigure the internal piping in the vessels to change the flow direction to flow upwards. GWE System Restart The GWE system was restarted on June 8, 2003. The effluent stream was discharged to a Baker tank configured with a float switch (shutoff). The baker tank was periodically emptied by vacuum trucks, which hauled the water to the Martinez Refinery for recycling. We advised MUD staff of our intention to resume discharge to the sanitary sewer. Prior to discharging to the sanitary sewer we collected effluent samples for laboratory analysis and provided MUD staff with the analytical results. We also recalibrated the flow meter and LEL meter. After obtaining MUD' s permission to discharge, we resumed discharge to the sanitary sewer on June 23, 2004. Mid-fluent GWE system samples collected on June 24, 2004 indicated the need for a carbon changeout. The GWE system was shut down on June 28, 2004 pending a carbon changeout, 0783 3