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0 <br /> A sample of the discharge water from this well showed no detection of diesel range <br /> hydrocarbons. With the consent of the RWQCB, operation of recovery well RW-4 was ceased on <br /> March 25, 2004. Cessation of recovery from this well is described in the Fourth Quarter 2003, <br /> First Quarter 2004 and Annual Groundwater Monitoring Report, dated March 31, 2004. <br /> Rebound of diesel was observed in well MW-14A, located immediately east of RW-4A shortly <br /> after pumping had ceased. Concentrations in well MW-14A have remained steady at between <br /> 0.22 mg/L, observed in June 2004 to the December 2004 concentration of 0.250 mg/L. <br /> Flow rates and total volume of groundwater produced by the recovery wells are monitored <br /> periodically by reading the totalizing flow meters installed in recovery well discharge pipelines. <br /> Volume estimates of product produced by the recovery wells are obtained by visual inspection of <br /> accumulated oil volume in the oil/water separator. Since the two operational recovery wells <br /> (RW-5A and EW-2) discharge to a common skimmer, there is no way of distinguishing recovery <br /> volume from individual wells, although based on the lack of product recovery immediately prior <br /> to startup of pumping from well EW-2, it is believed that most, if not all product recovered in the <br /> skimmer since late October 2002 has been produced by this well. Periodic inspections <br /> performed during the second and third quarters of 2004 describe the water discharged from <br /> recovery well RW-5A as "clear and odorless." Water produced by well EW-2 was consistently <br /> described as "clear with a diesel odor." <br /> In addition to normal operation of the product recovery system, recovery is enhanced by <br /> periodically inspecting monitoring wells for product and skimming with a bailer when it is <br /> encountered. Visual estimates of product volume from monitoring well skimming are made <br /> using a portable holding tank. Water and hydrocarbons produced by the recovery and <br /> monitoring wells are separated and the hydrocarbons are recycled. Well recovery discharge and <br /> the diesel oil extraction(skimmer) data are reported to the RWQCB semiannually. <br /> The existing groundwater extraction system is believed to be effective in controlling impacts to <br /> groundwater that originate in the central part of the plant. It is also effective in removing product <br /> from the system by inducing product movement toward monitoring wells MW-3 and MW-4 and <br /> by directly removing dissolved and free phase hydrocarbons. Free-phase hydrocarbon removal <br /> in well EW-2 is limited by the fact that the bulk of the floating product is above the submersible <br /> pump intake. <br /> Biofouling has resulted in significantly reduced groundwater production in recovery well <br /> RW-5A; therefore, hydrocarbon control and recovery from well RW-5A is no longer believed to <br /> be effective. Attempts to rehabilitate this well using mechanical agitation (jetting) in September <br /> 2002 were unsuccessful because of inhibited access to the well. The description of water <br /> produced by this well as clear and odorless indicates that hydrocarbons may no longer be present <br /> at this location. <br /> GeoTrans <br /> 4 <br />