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• remedial objectives Additionally, monitoring will be will be used as a tool to manage the dissolved-hydrocarbon plume Institutional Control. This management technology will be used to reduce the possibility of exposure to petroleum hydrocarbon-affected media at, or from, the site Generally, this is accomplished by restricting access to impacted media For example, since impacted groundwater will persist for some time during remediation, use would be restricted by prolubitirig instal- lation of drinking water wells at, or near, the site Establishing a WQLZ is also an aspect of institutional control Finally, a compliance contingency plan will be prepared for implementation in the event dissolved hydrocarbon migration threatens site environmental goals (Section 3) 5.3.2 Alternative 1: Soil Excavation and Ott Site Disposal In addition to the common elements mentioned above, this alternative consists of soil excava- tion and proper off-site disposal After removing clean overburden, impacted sod would be excavated and trucked off site for disposal at an appropriate landfill Up to 4,000 cubic yards of soil would be excavated and some fraction transported to a landfill (space for on-site treatment is limited) Shoring may be required to prevent caving, and the excavation would . be limited by surrounding improvements The United States Environmental Protection Agency (EPA) suggests that excavation with off- site landfill disposal should be considered for small soil volumes (less than 1,000 cubic yards) with high contaminant concentrations The benefits of this alternative are that it is easy to implement and implementation is rapid Limitations include contaminants are moved, not treated, the alternative is not cost-effective for large soil volumes or soil with low impact concentrations, and the alternative can pose long-term liability 5.3.3 Alternative 2: SVEBioventing This alternative consists of the following elements (1) design and installation of an SVFJbiovent system utilizing existing wells when possible, and (2) possible use of thermal oxidation or carbon adsorption(abatement unit)for treating system off gas Application of this alternative would require installation of an SVE/biovent system and possi- bly an abatement unit Air flow rates would be optimized to first enhance volatilization, then biodegradation Wells would be used to control flow regimes with an emphasis on air flow immediately within impacted soil volumes Operational flexibility is proposed as a means to address seasonal groundwater elevation changes and maximize biodegradation During peri- ods of high groundwater elevation, extraction flow rates will be decreased, and some SVE wells will be taken out of service These actions will maintain volatilization at the capillary 3201337B/1918REV 22 August 31, 1995