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{ <br /> i <br /> Criterion 5. s All of the approaches are comparable in term* of j <br /> short term effectiveness, ait:iough excavation would result in some + <br /> .� increased exposure or release of hydrocarboonol�timeue otohcor+pieti <br /> exposing soils to the atmosphere. ire 2-4 , <br /> remediation the excavation arproaches viii proLebly require <br /> weeks to complete s hiAn engineered extraction <br /> cap could ould be completed 1-3 <br /> could require Yee <br /> months. { <br /> Criterion 6.1 Soil excavation and on-site treatment would be the <br /> most effective long term remediation technique in so far as soils t <br /> could be excavated without endangering structures or further <br /> contaminating shallow groundwater. in attempting to remove sails i <br /> within the capillary sone the potential for introducing t <br /> hydrocarbons into t" shallow groundwater is high since the <br /> groundwater and oapillary scnD are in contact. Alternatives 2 and <br /> 4, l.th removal to a licenced landfill and site <br /> soil excavation w <br /> capping would also bn effective. Boil bioremediation, which <br /> entails the enhancement of the natural processes of degradation of <br /> contaminants would be only moderately e!lsottw because soils o <br /> o t <br /> the site are of wry low permeability. The inability to t <br /> oils will <br /> significantly enhance oxygen and nutrient leve)s in the sy <br /> severely limit this approach. Similar permeability consideration <br /> licit the applicability of soil vapor extraction. bilities ioi <br /> is ideally suited for soiin with relatively high pe a <br /> darey) and which are above the saturated sone. The soils at this <br /> site are clayey silt to silty clay with permesbAities of 10'' to <br /> he <br /> 10 daroye, and contaminated ichc taina water tilled pore spaceated within and s holdby <br /> capillary fringe, <br /> surface tension. <br /> Criterion 7.: The excavation alternatives have certain <br /> implementability difficulties associated with the structures on <br /> site (Figure 3, Dames a Moors, Nov. 1984) It is unlikely that all <br /> j of the contaminated material emn be removed without risking damage <br /> to structures on site. <br /> Criterion 8.s It is believed that all five approachen can achieve <br /> regulatory and community acceptance. The degree of disruption <br /> (visual, traffic, odors, noise) in the immediate site area is <br /> significantly greater for the excavatio alternatives, however, <br /> this would be expeoted to last only 2-4 weeks at most. The least <br /> disruptive alternative wou1G y disruption wouldxowever result in is not <br /> lose ! <br /> anticipated that this temporary } <br /> community acceptance. <br /> Criterion 9.s The three elternati•..:S are e`1 empasable in terms <br /> of impacts upon water conservation- t <br /> t <br /> 4 � <br />