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.�' _ �`��-.r. 1�� _. %',��'fa s�'^_ � �srr�ar���'�eeas�€�ris��ae�:ases��..�i3�v- ewe ;� ..:•sr�,:a�;.xa�-r. <br /> NEW <br /> RECOMMENDATIONS <br /> 1. Finish aeration of the excavated soil, and use this soil <br /> to back fill (appropriately compacted) the excavations to <br /> the surface. <br /> 2. Place three onsitevapor extraction wells; one each <br /> through the compacted back fill of the tank excavation, <br /> the compacted back fill of the eastern pump island area <br /> and the compacted back fill of the western pump island <br /> area, into native soil to the 40 foot depth, see <br /> r'igures 7A and 7C. <br /> 3. Manifold the vapor recovery wells to :-:common treatment <br /> facility near: the'.dumpster area of the site, seelFigure <br /> 7A. <br /> 4. Perform a vapor source - pilot test. <br /> 5. Perform a cast/benefit;analysis to determine the. best <br /> means to treat the':vapors..to.be `generatedby a: ''vapor <br /> recov ry. syste-m based on'the'pilot test. <br /> . el 6. Perform quarterly'-ground water monitoring. <br /> The rump dispensing area has been demolished and contaminated'soil <br /> beneath the dispensers:'has beea,.atcvated epthat <br /> the center dispenser and 'the 20-25 foot depths at the"eastern and <br /> western dispensers. Immediately after the completion of <br /> excavating each excavation was sampled. Aeration of the excavated <br /> contaminated soil was completed and Walton Engineering used this <br /> material as compacted back fill for all of the excavations to <br /> surface. The eastern and western excavations were back filled <br /> with 1/4" clean pea gravel to the twelve foot depth, the middle <br /> dispenser excavation was back filled with engineered compacted <br /> native aerated soil. The tank excavation was over excavated to <br /> the 25 foot depth, sampled and then back filled with 1/4" pea <br /> gravel to the 12 foot depth and compacted native soil to the 2 <br /> foot depth. <br /> Western Geo-Engineers (WEGE) installed three vapor recovery wells <br /> on site. Vapor recovery well EX was installed within the <br /> overexcavated/back filled tank field, vapor recovery well P1 was <br /> installed within the overexcavated/back fill of pump island 1 <br /> (eastern most island) , and vapor extraction well P3 was installed <br /> within the overexcavated/back fill--of-pump-island-3:-.-(western--most-------------- -- --- <br /> island) .. These wells were later manifolded with PVC pipe .to a <br /> blower that exhausted into charcoal canisters for an 11 day source <br /> test. Prior to the source test all ground water monitoring wells <br /> page 2 <br />