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 Prioritizing Criteria (cont’d)  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:

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, ,  John Vierow, SAIC, ,