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December 30, 1994 • • Page 4 reduce hydrocarbon mass in the capillary fringe and groundwater through biostimulation. • Alternative 2: Initially, use a less intensive SVE program to remove petroleum hydrocarbon mass. Once petroleum hydrocarbon mass has been significantly diminished, use air sparging in conjunction with SVE to further reduce hydrocarbon mass in the capillary fringe and groundwater through biostimulation. • Alternative 3: Excavation of impacted soils followed by on-site treatment using landfarming techniques to reduce petroleum hydrocarbon mass through volatilization and biodegradation. Backfill the soils once target concentrations have been attained. Alternative Evaluation Technical, institutional, environmental protection, and economic criteria were used to evaluate the alternatives. A soil vapor extraction test, a soil investigation, and a biofeasibility study were completed prior to preparation of this document. Data from these investigations were considered in the evaluation process. The results of the evaluation process are briefly outlined below. • Technical: Considering short term effectiveness, Alternative 3 was ranked most favorable while Alternative 2 was ranked least favorable. The point that ranked Alternative 3 above Alternative 1 was the increase in short-term effectiveness associated with a higher mass reduction rate. Alternative 2 would promote the least amount of air flow to the impacted soils and is therefore the least favorable alternative in the short term. Alternatives t,and 3 would promote greater air flow and are therefore preferred. It should be noted that the benefit described for the short-term may be minor when viewed in the long term. The data suggest that the application of either Alternative I or Alternative 3 will be effective in the remediation of soils within a two year time span. e Institutional: All of the proposed alternatives can achieve institutional requirements as outlined in CCR, Title 23, Article 11. Application of either alternative will similarly affect the community. • Environmental Protection: The three alternatives provide a high degree of environmental protection. The alternatives were ranked equally considering environmental protection. • Economic: Based on economic analysis, the alternatives were ranked from most economical to least economical. The estimated expenses for the implementation of Alternative I is $204,000, Alternative 2 is $248,000, and Alternative 3 is $260,000. Alternative I is associated with moderate 3100011b/wkpin