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... Work Plan for Refined Plume Definition and Management of Floating Product-7500 W IIth St., Tracy, CA. Page 36 probe and tape of a groundwater depth meter with a paste that changes color when it comes into contact with a fuel hydrocarbon. The paste is applied to the lower approximate one foot of the tape line, as measured from the tip of the probe. The pretreated probe line is then carefully and slowly lowered into the well until the meter's alarm sounds. At that point, the probe tape is immediately held steady so that the thickness of floating product is not mis-measured by allowing higher portions of the pasted tape to come into contact with floating product. The tape and probe is then carefully withdrawn from the well and the apparent thickness of floating product is noted by measuring the distance from the probe tip to the highest point on the tape where the paste has changed color. �. Note: As discussed in Section 5.2.1, the thickness of floating product measured in a well is described as the "apparent thickness" and is generally greater than the actual thickness of floating product present in the formation. 9.2.2 Pum Apparatus and Pumping Technique ,i When the thickness of floating product in Monitoring Well MW-7 has been measured, a Wilden Model M2, 30•gallon-per-minute (gpm) capacity, air-activated, diaphragm suction pump is used to lift floating product from the well and discharge it into a 55-gallon steel drum equipped with a closable top. The pump is powered by a trailer-mounted, 185-cubic feet per minute (cfm) capacity, diesel-powered air compressor. Compressed air is supplied to the pump via a flexible hose, which is attached to the compressor via an air flow regulating valve. Use of this type of pump and power source obviates the need to provide electrical power to Monitoring Well MW-7, which is remote from an installed electrical supply. ... The Wilden pump is dedicated to the purpose of removing floating product from Monitoring Well MW-7 because it becomes heavily-contaminated when used for that purpose and, thus, it is rendered unsuitable for any other use. The pump inlet is attached to a flexible, transparent, 0.5-in diameter, plastic suction pipe. This permits the condition of the pumped fluid to be observed so that the quantity of groundwater that is extracted from the well in addition to the floating product can be kept to a practical minimum. The pump suction hose is connected to a 0.5-in diameter, 10-ft. long piece of rigid plastic pipe, or lance, which is lowered into the well until its tip is immersed below the surface of the floating product, but not to a depth greater than the interface between groundwater and the floating product. The suction pipe and lance assembly includes a regulating/shut off valve. The tip of the suction pipe is lowered into the well to a depth just `— below the surface of the floating product. The pump discharge line is also made from flexible, transparent, 0.5-in diameter plastic pipe. The discharge pipe directs the recovered product into the 55-gallon drum that is staged at the well head. y SJC