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Harding Lawson Associates <br /> VIII DISCUSSION OF REMEDIAL ALTERNATIVES <br /> f <br /> - HLA has-formulated -several alternatives to mitigate migration of gasoline -' <br /> constituents in the ground water. Each alternative includes withdrawal and <br /> handling of ground water and requires a pumping test. <br /> A ground water extraction system, a French drain, or both appear to be <br /> feasible methods of source control at this facility, The ground-water system <br /> would entail pumping from MW-7 in.the tank backfill. The French drain would <br /> consist of a constructed zone of high permeability along the downgradient por- <br /> t <br /> r tion of the site. The dimensions of the French drain could range from 100 to <br /> I. 150 feet long and 5 feet deep. Either ground-water extraction or a French <br /> drain would require off-site disposal or on-site treatment prior to <br /> discharge. Off-site disposal involves containerizing all extracted water and <br /> transporting it to a licensed facility. Extracted water could be temporarily <br /> held:in`a large Baker tank pending off-site disposal. A licensed hauler would <br /> E <br /> be required to transport the Baker tank. ' <br /> G On-site treatment will most likely involve carbon-filtration, air- .' <br /> strippi . in-site baremedi <br /> atiorn,. or some combination of the three. The ; <br /> } equipment would be. designed to handle types and concentrations of chemicals <br /> present at:-the site; as well-as the_rate-at which the water could be with- <br /> drawn. -Any equipment required would be operated an <br /> drmaintained at the site. <br /> 3. Depending upon the methodology choosen, on-site treatment may also involve <br /> . the discharge of treated water. It may be possible to discharge this water <br /> I`3 into a tributary of the San Joaquin River, a West Side Irrigation District <br /> canal, or the City'sanitary sewer system. Discharging into a tributary of the <br />