Preliminary Analysis of Alternatives for the Long Term Management of Mercury

1. Preliminary Analysis of Alternatives for the Long Term Management of Mercury John Vierow Science Applications International Corp. Reston, VA May 1, 2002

2. SAIC’s Role • SAIC initiated project in February 2002 under contract to U.S. EPA Office of Research and Development • EPA project manager is Paul Randall • Results are preliminary

3. Project Objectives • Evaluate potential options for long-term mercury management • Use existing information in the context of decision tools • Use methodology as a basis for future decision-making

4. Methodology • Uses Expert Choice software • Identify potential or candidate alternatives • Only considering elemental mercury • Considering storage, and treatment/disposal • Identify evaluation criteria • Rank criteria and prepare value judgments • Evaluate alternatives against criteria • Summarize results

5. Step 1. Identify Alternatives • Considered 11 potential alternatives: • Three storage alternatives: standard above-ground storage, mine storage, hardened storage • Eight treatment/disposal alternatives, consisting of two different general treatment methods and four different disposal methods: • Two treatment methods: Stabilization/ amalgamation, and mercury selenide treatment • Four disposal methods: RCRA C landfill, monofill, mine, concrete bunker • Did not detail locations or distinguish between companies/ vendors

6. Step 2. Identify Evaluation Criteria • Considered 15 different criteria, grouped into cost and non-cost components • Six principal non-cost components included regulatory compliance, implementation considerations, maturity, catastrophic risks, environmental performance, and public perception • Additional sub-criteria identified for environmental performance and others • Two cost components: initial and operational

7. Step 3: Prioritizing Criteria • Results can be evaluated with or without costs • Costs (implementation and operational) initially accounted for 50% of overall ranking of alternative • Importance of costs can be increased, decreased, or eliminated

8. Conducted pairwise comparison for each criterion (brainstorming) Requires about 30 ‘value judgment’ comparisons Weighting factors result for each of the criterion. Verbal judgments are translated to numerical settings: Prioritizing Criteria (cont’d)

9. Prioritizing Criteria (cont’d) Non-Cost Criteria

10. Step 4: Evaluating Alternatives Data were collected for each alternative using resources such as: • Other reports (EC) and conferences • EPA/ DOE treatment technology performance reports • DLA EIS information collection • General literature

11. Evaluating Alternatives (cont’d) • Within each criterion, 2-4 intensities (grades) were possible • Requires about 40 pairwise comparisons between intensities for making ‘value judgments’ • The number of intensities depended on differences between alternatives • Both quantitative and qualitative information can be used

12. Evaluating Alternatives (cont’d) Example: Non-Cost Criteria • Criterion: Implementation - Engineering requirements • Three possible intensities: use of existing facilities (most favorable), requiring new facilities, or mined cavity construction (least favorable) • Alternative 1 (Standard storage): use of existing facilities • Alternative 2 (Stabilization/ amalgamation treatment plus monofill): requires new facilities • Nine other alternatives evaluated, for 13 non-cost criteria

13. Evaluating Alternatives (cont’d) Example: Cost Criteria • Criterion: Implementation and Operational Costs • Three possible intensities: low, medium, high • Alternative 1 (Standard storage): Low implementation (if using existing facilities), high ongoing (accounts for temporary nature of storage) • Ten other alternatives evaluated

14. Step 5: Summarize Results • Overall findings, using previously prepared pairwise comparisons • Sensitivity/what-if: evaluating alternatives based on different criteria value judgments • Uncertainty: evaluating differences in assigned intensities. Changes in one assignment had small effect on results

15. S/A: stabilization/ amalgamation

16. Summary and Conclusions • Used Expert Choice to evaluate potential management alternatives for mercury • Evaluates alternatives against criteria; value judgments are used to prioritize criteria • Costs can be evaluated with, or separated from, other criteria

17. Summary and Conclusions (cont’d) Advantages include: • Provides documentation for a complex problem • Forces decisions in prioritizing importance of criteria • Can use both qualitative and quantitative information • Allows flexibility

18. Summary and Conclusions (cont’d) Limitations include: • Process will always have subjective components • Differences of opinion by experts and stakeholders in subjective components can be handled by consensus, averaging, or Monte Carlo analysis • Will always have data gaps and uncertainties

19. Next Steps Obtain comments on approach from workshop participants • Paul Randall, U.S. EPA Office of Research and Development, 513-569-7673, randall.paul@epa.gov • John Vierow, SAIC, 703-318-4551, vierowj@saic.com