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+r Work Plan far Refined Plume Definition and Management offloatingProduct-7500 W 11th St., Tracy, CA. Page R �. By adjusting the rate at which air is fed to the pump by use of the valve regulating the supply of air from the compressor and regulating the rate at which fluid is raised from the well by use of the valve on the suction riser, experienced operators then skim floating product from the surface of the groundwater in the well while keeping the pumped quantity of groundwater that is free of floating product to a minimum. 9.2.3 Post-pumping Procedures After the well is purged of floating product, the material is pumped into the 55-gallon steel drum mobilized to the well head for that purpose, which will then be conveyed to the 7500 West Eleventh Street property. There it is staged for later transport to a permitted recycling facility where the fuel products will be separated from the water and recycled in beneficial use. When the 1000-gallon holding tank described in Section 7.7.5 above has been procured and installed on that property, the contents of the drum used at the well head will be decanted into it so that a substantial volume of purged floating product and groundwater can be stored w. on site and more economically transported to the treatment facility. If any difficulty arises in the field that would prevent extraction of floating product from .. Monitoring Well MW-7 by suction pumping, hand bailing of the free product will be substituted as an interim procedure, with the removed product being managed in the same manner as is described above. y 9.2.4 Floating Product Removed to Date As was noted in Section 5.2.1, the first round of purging of floating product from Monitoring Well MW-7 occurred on November 8, 2003, when, prior to purging, the thickness of floating product prior to purging was 0.58 ft. Since then, three additional purgings of LNAPL from that well were performed, on November 15, 2003, November 22, 2003 and December 21, 2003. By November 22, 2003, no floating product was measurable on the groundwater prior to its being purged and no more than a sheen was observed on the extracted groundwater. After a delay of one month less than one ounce of LNAPL was recovered from the well when it was again purged on December 21, 2003. Records of thicknesses of LNAPL that have been measured in Monitoring Well MW-7 are recorded in Table 3. As is described above, initially, floating product from Monitoring Well MW-7 was purged on a weekly basis. However, since a significant thickness of floating product failed to reappear `r in the well seven days after the November 15th purging, SJC reduced the purging frequency to once per month and, on December 21, 2003, to a quarterly frequency to achieve a cost- effective operation. Purging is to be repeated on a quarterly schedule until such time as a larger-scale floating product removal system is constructed, or floating product ceases to be present in Monitoring Well MW-7 for a period of six months. It is instructive to review the results of the LNAPL-purging rounds that have been completed to date in the context of the likely effectiveness of that interim measure to influence significantly the mass of LNAPL present in the subsurface beneath the site. If it is assumed that the porosity of the Monterey sand filter pack around the slotted 2-in.-diameter casing of sic w