vvEPA
United States
Environmental Protection
Agency
Economic and Environmental
Analysis of Technologies to
Treat Mercury and Dispose in a
Waste Containment Facility
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EPA/600/R-05/157
April 2005
ECONOMIC AND ENVIRONMENTAL ANALYSIS OF
TECHNOLOGIES TO TREAT MERCURY AND DISPOSE IN A
WASTE CONTAINMENT FACILITY
by
Science Applications International Corporation
20201 Century Blvd.
Germantown, MD 20874
for
Paul Randall
Office of Research and Development
U.S. Environmental Protection Agency
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
Sustainable Technology Division
National Risk Management Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
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Mercury Environmental and Economic Study Final Report April 2005
NOTICE
The U.S. Environmental Protection Agency through its Office of Research and Development, funded and
managed the research described here under delivery order number 1108, GSA Environmental Services
Contract GS-10F-0076J to (name). It has been subjected to the Agency's peer and administrative review
and has been approved for publication as an EPA document. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
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Mercury Environmental and Economic Study Final Report April 2005
FOREWORD
The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the
Nation's land, air, and water resources. Under a mandate of national environmental laws, the Agency
strives to formulate and implement actions leading to a compatible balance between human activities and
the ability of natural systems to support and nurture life. To meet this mandate, EPA's research program is
providing data and technical support for solving environmental problems today and building a science
knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect
our health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory (NRMRL) is the Agency's center for
investigation of technological and management approaches for preventing and reducing risks from
pollution that threaten human health and the environment. The focus of the Laboratory's research program
is on methods and their cost-effectiveness for prevention and control of pollution to air, land, water, and
subsurface resources; protection of water quality in public water systems; remediation of contaminated
sites, sediments and ground water; prevention and control of indoor air pollution; and restoration of
ecosystems. NRMRL collaborates with both public and private sector partners to foster technologies that
reduce the cost of compliance and to anticipate emerging problems. NRMRL's research provides
solutions to environmental problems by: developing and promoting technologies that protect and improve
the environment; advancing scientific and engineering information to support regulatory and policy
decisions; and providing the technical support and information transfer to ensure implementation of
environmental regulations and strategies at the national, state, and community levels.
This publication has been produced as part of the Laboratory's strategic long-term research plan. It is
published and made available by EPA's Office of Research and Development to assist the user
community and to link researchers with their clients.
Sally Gutierrez, Director
National Risk Management Research Laboratory
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Mercury Environmental and Economic Study Final Report April 2005
TABLE OF CONTENTS
NOTICE i
FOREWORD ii
AUTHORS AND REVIEWERS vii
ACRONYMS viii
EXECUTIVE SUMMARY S-l
S.I Background S-2
S.2 Choice of Technologies S-2
S.3 Environmental Analysis S-2
S.4 Economic Analysis S-3
S.5 Results S-4
S.5.1 Environmental Analysis - Results S-5
S.5.2 Economic Analysis - Results S-7
S.6 Conclusions and Recommendations S-8
1.0 INTRODUCTION 1-1
1.1 Background 1-1
1.2 Scope of Work 1-2
1.3 Approach 1-3
1.3.1 Choice of Three Technologies 1-3
1.3.2 Environmental Analysis 1-3
1.3.3 Economic Analysis 1-4
2.0 SELECTION OF TECHNOLOGIES FOR EVALUATION 2-1
2.1 Criteria for Selection of Technologies 2-1
2.1.1 Identifying Critical Issues 2-2
2.1.2 Evaluation of the Technologies 2-2
2.1.3 Identifying Candidate Processes 2-2
2.2 Scoring Results 2-3
2.2.1 Option A 2-3
2.2.2 Option B 2-3
2.2.3 Option C 2-4
2.2.4 Option D 2-4
2.2.5 Option E 2-4
2.2.6 Option F 2-4
2.3 Conclusions 2-5
3.0 ENVIRONMENTAL ANALYSIS using the analytic hierarchy process 3-1
3.1 Finalized List of Alternatives 3-1
3.2 Assumptions and Ground Rules 3-1
3.3 AHP Brainstorming Session 3-2
3.3.1 The Goal 3-2
3.3.2 Development of Criteria and Subcriteria 3-2
3.3.3 Pairwise Comparison to Rank the Criteria and Subcriteria 3-2
3.3.4 Development of "Intensities" for each Criterion and Subcriterion 3-2
3.3.5 Assignment of Intensities to Alternatives 3-3
3.4 Results of the Baseline Expert Choice Analysis 3-3
3.4.1 Factors Which Influence the Scoring of Mobile Treatment Versus Centralized Treatment
Alternatives 3-4
3.4.2 Factors Which Influence the Scoring of Macroencapsulation Versus Non-Macroencapsulation
Alternatives 3-5
3.4.3 Factors Which Influence the Scoring of the Three Technology Options 3-5
3.5 Sensitivity and Uncertainty Analyses 3-6
in
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Mercury Environmental and Economic Study Final Report April 2005
3.5.1 Sensitivity Analyses 3-6
3.5.2 Uncertainty Analyses 3-7
3.6 Release Rates of Mercury 3-8
4.0 ECONOMIC ANALYSIS 4-1
4.1 Assumptions and Bases for Cost Estimates 4-2
4.1.1 Background and General Assumptions 4-2
4.1.2 Mercury Treatment Processes 4-4
4.
4.
4.
4.
4.
.2.1 Option A 4-4
.2.2 Option B 4-7
.2.3 Option C 4-9
.2.4 Cost Input Factors Common to All Treatment Technologies 4-12
.2.5 Operating and Maintenance Costs 4-12
4.1.3 Macroencapsulation 4-14
4.1.4 Mobile Treatment 4-15
4.1.5 Content of Appendices C andD 4-17
4.2 Monofill 4-18
4.2.1 Monofill Requirements per Code of Federal Regulations 4-18
4.2.2 Monofill Cost Bases 4-19
4.2.3 Monofill Costs 4-25
4.3 Storage 4-26
4.3.1 Long-Term Storage 4-27
4.3.2 Storage Costs Associated with Treatment and Disposal Alternatives 4-27
4.4 Transportation 4-28
4.4.1 Centralized Treatment 4-28
4.4.2 Mobile Treatment 4-29
4.4.3 Long-Term Storage - Transportation of Elemental Mercury 4-29
4.4.4 Miscellaneous 4-29
4.5 Uncertainties 4-29
4.5.1 Background Information on Uncertainties in Capital Costs and Life Cycle
Cost Estimates 4-30
4.5.1.1 Construction Projects/Capital Costs 4-30
4.5.1.2 EPA Guidance on Uncertainty in Life Cycle Cost Estimates 4-31
4.5.2 Uncertainties in Costs of Elements of the Long-Term Disposal of Elemental Mercury 4-31
4.5.3 Calculation of Uncertainties 4-33
4.6 Results and Interpretation 4-34
5.0 REFERENCES 5-1
5.1 Complete List of References 5-1
5.2 References Used for Comparative Analyses of Options A-F 5-7
APPENDIX A: DESCRIPTION OF THE ANALYTIC HIERARCHY PROCESS
APPENDIX B: FACTORS AND PHENOMENA THAT NEED TO BE EVALUATED WHEN
ASSIGNING INTENSITIES TO ALTERNATIVES
APPENDIX C: OPTION A PROCESS - INPUT INFORMATION FOR COST ESTIMATES
APPENDIX D: OPTION B PROCESS - INPUT INFORMATION FOR COST ESTIMATES
APPENDIX E: INPUT TO MONOFILL COSTS - OPTION A PROCESS
APPENDIX F: INPUT TO MONOFILL COSTS - OPTION B PROCESS
APPENDIX G: INPUT TO MONOFILL COSTS - OPTION C PROCESS
IV
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LIST OF TABLES
Table S-l. Environmental Analysis - Summary of Baseline Results for 12 Evaluated Alternatives S-10
Table S-2. Environmental Sensitivity Analysis S-ll
Table S-3. Uncertainty Analysis for Mercury Management Alternatives S-12
Table S-4. Net Present Value Estimates S-13
Table S-5. Net Present Value Estimates Expressed as Cost per Metric Ton of Treated Mercury S-14
Table 2-1. Criteria Chosen for the AHP Analysis in Preliminary Analysis of Alternatives for the Long-
Term Management of Excess Mercury, August 2002 2-1
Table 2-2. Elemental Mercury Treatment Technology Evaluation 2-6
Table 2-3. Elemental Mercury Treatment Technology Evaluation 2-8
Table 3-1. Goal, Criteria, and Subcriteria from EPA/SAIC AHP Brainstorming Session, June 17
and 18,2004 3-10
Table 3-2. Expert Choice Matrices for Criteria and Subcriteria 3-12
Table 3-3. Assignment of Intensities to Treatment and Disposal Alternatives 3-13
Table 3-4. Environmental Analysis - Summary of Baseline Results for 12 Evaluated Alternatives 3-14
Table 3-5. Environmental Sensitivity Analysis 3-15
Table 3-6. Uncertainty Analysis for Mercury Management Alternatives 3-16
Table 3-7. Preliminary Release Rates for Mercury Monofill Disposal 3-17
Table 4-1. Current U.S. Government Mercury Stockpiles 4-3
Table 4-2. Major Equipment for the Option A Process 4-6
Table 4-3. Material Costs for Option A Process 4-7
Table 4-4. Major Equipment for the Option B Process 4-10
Table 4-5. Material Costs for Option B Process 4-12
Table 4-6. Major Equipment for the Option C Process 4-13
Table 4-7. Material Costs for the Option C Process 4-13
Table 4-8. Factors Used to Estimate Fixed Treatment Facility Capital Costs 4-14
Table 4-9. Factors Used to Estimate Treatment and Macroencapsulation O&M Costs 4-14
Table 4-10. Major Equipment for Macroencapsulation 4-15
Table 4-11. Material Costs for Macroencapsulation Process 4-15
Table 4-12. Factors Used to Estimate Fixed Macroencapsulation Facility Capital Costs 4-16
Table 4-13. Factors Used to Estimate Mobile Treatment Facility Capital Costs 4-17
Table 4-14. Factors Used to Estimate Mobile Macroencapsulation Facility Capital Costs 4-18
Table 4-15. Factors Used to Estimate Monofill Construction Costs 4-25
Table 4-16. Net Present Value Estimates 4-36
Table 4-17. Net Present Value Estimates Expressed as Cost per Metric Ton of Treated Mercury 4-37
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Mercury Environmental and Economic Study Final Report April 2005
LIST OF FIGURES
Figure S-l ARC Criteria and Subcriteria Relative Weights S-15
Figure 4-1. Option A Process 4-5
Figure 4-2. Option B Sulfide Process 4-8
Figure 4-3. Option C Process 4-11
Figure 4-4. Landfill Cross-Section and Plan Design 4-21
Figure 4-5. Landfill Liner Cross-Section 4-22
Figure 4-6. Expected Cost Accuracy Along the Superfund Pipeline: Exhibit 2-3 from EPA (2000).... 4-32
VI
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Mercury Environmental and Economic Study Final Report April 2005
AUTHORS AND REVIEWERS
This report was prepared by the following authors:
SAIC
Project Manager: Geoffrey D. Kaiser
Joseph Skibinski
William Toman
John Vierow
MPR Associates
Bill Dykema
Eric Ten Siethoff
SAIC INTERNAL REVIEWERS
Larry Deschaine
John DiMarzio
EPA REVIEW TEAM
Paul Randall, EPA COTR
Linda Barr
Hugh Davis
Juan Parra
Dave Topping
EPA EXTERNAL REVIEWER
Dr. Ernie Stine, Shaw Environmental
vn
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ACRONYMS
AHP Analytic Hierarchy Process
ASTM American Society for Testing and Materials
BNL Brookhaven National Laboratory
CFR Code of Federal Regulations
COTR Contracting Officer's Technical Representative
CQA Construction Quality Assurance
CTA Centralized Treatment Alternative
DLA Defense Logistics Agency
DNSC Defense National Stockpile Center
DOD Department of Defense
DOE Department of Energy
DOT Department of Transportation
EIS Environmental Impact Statement
EPA Environmental Protection Agency
HOPE High Density Polyethylene
LCCE Life-Cycle Cost Estimate
LCRS Leachate Collection and Removal System
LDR Land Disposal Restrictions
LDS Leak Detection System
ME Macroencapsulation
MT Metric Tons
MTA Mobile Treatment Alternative
NME No Macroencapsulation
MMEIS Mercury Management Environmental Impact Statement
NEI Nuclear Energy Institute
NPV ' Net Present Value
O&M Operations and Maintenance
OMB Office of Management and Budget
ORD Office of Research and Development
OSW Office of Solid Waste
PBT Persistent, Bio-accumulative, and Toxic
RCRA Resource Conservation and Recovery Act
SAIC Science Applications International Corporation
SEK Swedish Kroner
SPSS Sulfur Polymer Solidification/Stabilization Process
TCLP Toxicity Characteristic Leaching Procedure
TLV Threshold Limit Value
UTS Universal Treatment Standard
WF Weighting Factor
WIPP Waste Isolation Pilot Plant
Vlll
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Mercury Environmental and Economic Study Final Report April 2005
ECONOMIC AND ENVIRONMENTAL ANALYSIS OF TECHNOLOGIES TO TREAT
MERCURY AND DISPOSE IN A WASTE CONTAINMENT FACILITY
EXECUTIVE SUMMARY
This report is intended to describe an economic and environmental analysis of a number of
technologies for the treatment and disposal of elemental mercury.: The analysis considers three treatment
technologies that convert elemental mercury into a stable form of mercury. The technologies are
identified as Option A, Option B, and Option C in this report. Several vendors use processing techniques
and/or prepare economic information which has been claimed as proprietary; however, only non-
proprietary information is presented in this report.
Each of the three treatment technologies is subject to a number of variations that include either a
centralized treatment facility or one or more mobile treatment facilities, followed by either
macroencapsulation or no macroencapsulation2, with ultimate disposal in a monofill. Thus, there are
twelve treatment and disposal alternatives all together:
1. Option A + no macroencapsulation + centralized treatment
2. Option A + no macroencapsulation + mobile treatment
3. Option A + macroencapsulation + centralized treatment
4. Option A + macroencapsulation + mobile treatment
5. Option B + no macroencapsulation + centralized treatment
6. Option B + no macroencapsulation + mobile treatment
7. Option B + macroencapsulation + centralized treatment
8. Option B + macroencapsulation + mobile treatment
9. Option C + no macroencapsulation + centralized treatment
10. Option C + no macroencapsulation + mobile treatment
11. Option C + macroencapsulation + centralized treatment
12. Option C + macroencapsulation + mobile treatment
Three different masses of mercury are being considered for each of the 12 alternatives:
a. 5,000 metric tons,
b. 12,000 metric tons, and
c. 25,000 metric tons.
Thus, 36 treatment and disposal alternatives are being considered. In addition, cost estimates have
been prepared for storage of the three masses of elemental mercury in aboveground facilities, making a
total of 39 cost estimates in all. It is assumed that 1,000 MT per year is treated and disposed of
independent of the total mass. For the storage alternatives, it is assumed 5,000 MT is already in storage
(approximately consistent with the existing amount in government stockpiles) and that the additional
elemental mercury becomes available over 12 and 25 years respectively for the 12,000 MT and
25,000 MT alternatives (e.g., due to chlor-alkali plant closure).
1 Note - the analysis is restricted to the treatment and disposal or long-term storage of elemental mercury. This report does not
consider the treatment and disposal of mercury-containing wastes nor radioactive mercury.
No other waste will be commingled with the treated mercury in these monofills. Macroencapsulation in this report is a separate
step after stabilization during which the treated mercury is sealed in polyethylene to limit mercury transport to the environment.
If the stabilization process ends with the solidified product in some form of container, this container will be encapsulated in
polyethylene in the macroencapsulation alternative. "No macroencapsulation" means that the stabilized mercury will be placed
in the monofill exactly as it is generated by the stabilization process.
S-l
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Mercury Environmental and Economic Study Final Report April 2005
The results are presented in Section S.5 of this summary with conclusions and recommendations in
Section S.6. Sections S.I through S.4 discuss the background, approach and assumptions.
S.I Background
The use of mercury in products and processes is decreasing. It is likely that in the future, the supply of
mercury will far exceed the demand for mercury. In addition, the Department of Defense (DOD) and the
Department of Energy (DOE) have stockpiled approximately 6,000 Metric Tons (MT) of mercury that is
no longer needed. Therefore, strategies must be devised for managing the excess mercury. Currently, the
most prevalent method is to store the elemental, liquid form in flasks and stockpile them in warehouses.
The risks associated with this method of storing elemental mercury have been extensively discussed in the
Final Mercury Management Environmental Impact Statement (DLA 2004).
Independently of DLA, EPA's Offices of Research and Development (ORD) and Solid Waste (OSW)
have been working with DOE to evaluate technologies for permanently stabilizing and disposing of
wastes containing mercury (e.g., DOE 1999a-1999e; USEPA 2001, 2002a,b). Other comprehensive
studies carried out in the recent past include one by SENES Consultants (SENES 2001) who produced a
draft report for Environment Canada evaluating 67 technologies for the retirement and long-term storage
of mercury. In addition, OSW is considering revisions to the Land Disposal Restrictions (LDRs) for
mercury. Land disposal of hazardous wastes containing greater than 260 mg/kg mercury is currently
prohibited. OSW has pursued options which would allow land disposal of waste containing greater than
260 mg/kg mercury; however, no specific revisions are forthcoming (See Section 1.1 of this report for
further information).
Using the above-referenced work as a starting point, EPA prepared report EPA/600/R-03/048,
Preliminary Analysis of Alternatives for the Long-Term Management of Excess Mercury
(USEPA 2002c). USEPA (2002c) Appendix B provides a concise review of the SENES 2001 mercury
treatment technologies and why certain treatment technologies were not selected by the USEPA for
further analysis. The purpose of the present work is the logical next step, which is to focus on just a few
of the alternatives considered in EPA/600/R-03/048. This allows a more detailed breakdown and analysis
of the stabilization/amalgamation alternatives than was possible in EPA/600/R-03/048, and also allows
more effort to be applied to developing cost information.
S.2 Choice of Technologies
The first task was to narrow the choice of treatment technologies to just three.
The first step was to review the available literature and to hold consultations with EPA personnel in
ORD and OSW. This resulted in a short-list of 6 treatment technologies identified as Options A through
F. The list was then winnowed down to 3 treatment technologies by using the Kepner-Tregoe decision-
making method as a tool3. Section 1.3.1 contains a brief summary of this method. It is further described
in Section 2 and its use resulted in a final list of three treatment technologies, Options A, B, and C. See
DOE (200la).
S.3 Environmental Analysis
The method chosen for the environmental comparison of the twelve treatment and disposal
alternatives is the Analytic Hierarchy Procedure (AHP) as embodied in the Expert Choice software. This
is the same tool that was used for the analysis in EPA/600/R-03/048. Different selection criteria were
used in the present AHP analysis than in the USEPA 2002c study to better define the
3 The Kepner-Tregoe method assigns a weight to each of a number of selected criteria. Each alternative is then scored against
each criterion (e.g., on a scale from 1-10). The scores and corresponding weights are multiplied and then summed for each
criterion, leading to a numerical ranking.
S-2
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Mercury Environmental and Economic Study Final Report April 2005
strengths/weaknesses and data gaps of each treatment technology. The AHP process is described in
Section 1.3.2. Information and details of Expert Choice software and its usage are described in
Appendices A and B.
The AHP was carried out as a brainstorming exercise by a team from SAIC and EPA. The team first
developed the goal of the analysis: minimize environmental impacts during the life-cycle of the treatment
and disposal of elemental mercury. Based on this goal, the team then developed and ranked criteria
against which each alternative was compared. Criteria with largest weight and smallest rank as the most
important issues. These criteria and subcriteria with relative weightings and rankings are provided in
parentheses were:
Cl. During routine operation of the stabilization facility (weighting: 0.065, ranking: 4)
Cl-1. -solid waste streams (other than final product) (0.750)
Cl-2. -atmospheric discharges (0.250)
C2. During abnormal or accidental operation of the stabilization facility (weighting: 0.188,
ranking: 3)
C2-1. -elemental mercury spills (0.833)
C2-2. -spills other than elemental mercury (0.167)
C3. During transportation (weighting: 0.216, ranking: 2)
C3-1. -of mercury to stabilization facility (0.747)
C3-2. -of stabilized waste to monofill (0.119)
C3-3. -of reagents to stabilization facility (0.134)
C4. During decommissioning of the stabilization unit (weighting: 0.038, ranking: 5)
C5. During storage in the monofill (weighting: 0.493, ranking: 1)
C5-1. - expected difficulty of maintaining environmental conditions (up to 40 years)
(0.200)
C5-2. -expected long-term susceptibility to degradation (0.800)
The weights against each criterion or subcriterion are an indication of the relative importance and
were assigned by the team using a brainstorming process known as "pairwise comparison." The relative
importance of criteria, from most to least is shown in Figure S-l. Each of the 12 treatment and disposal
alternatives were then assigned an "intensity" or score relative to each of the criteria or subcriteria.
Section 3.3 and USEPA 2002c provide details on "pairwise comparisons" and "intensities". Summing
these scores leads to a relative ranking of the alternatives, see Section S.5.
The above weightings show that, of the first-level criteria, the SAIC/EPA team assigned the greatest
weight (almost 50%) to storage in the monofill. Of the subcriteria below storage in the monofill (C5-1
and C5-2), the greatest weight (80%) was assigned to the long-term susceptibility of the waste form to
degradation (e.g., changes in the disposal environment as discussed in Section 3.3.5 and Appendix B).
Therefore, scores for individual alternatives were strongly influenced by the team's expectations about
long-term behavior in the monofill.
The team also assigned considerable importance to transportation accidents, especially those that
could involve the spillage of elemental mercury.
S.4 Economic Analysis
As described above, 36 treatment and disposal alternatives are being considered. In addition, cost
estimates have been prepared for storage of the three masses of elemental mercury in aboveground
facilities, making a total of 39 cost estimates in all.
Each of the thirty-six cost estimates for treatment and disposal includes the following elements4:
4 Note: the cost results do not contain estimates of the costs that might be incurred should there be an accident or malfunction
(e.g., a spillage of elemental mercury during transportation or excessive leachate escaping from the monofill).
S-3
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Mercury Environmental and Economic Study Final Report April 2005
• Capital costs for the treatment facility,
• Capital costs for the macroencapsulation facility (if part of the alternative),
• Operating and maintenance costs for the treatment process,
• Operating and maintenance costs for the macroencapsulation process (if part of the
alternative),
• Costs associated with the mobile treatment alternatives,
• Transportation costs associated with each alternative,
• Costs of storing elemental mercury prior to treatment,
• Decommissioning costs for the treatment facilities,
• Monofill engineering and construction costs,
• Monofill operating costs, and
• Costs of maintaining and monitoring the monofill for a thirty-year period following its
closure.
Each of the three storage alternatives contains the costs of maintaining the existing stockpile
(assumed to be 5,000 MT) in storage, adding to storage space as necessary, and transporting elemental
mercury to the storage facility(ies).
The SAIC team developed process flow diagrams for each of the three technologies and the
associated macroencapsulation process and a preliminary design for the monofill such that 1,000 MT of
elemental mercury will be treated and disposed of each year.
The sources of information for the cost estimates included:
• Published work by the vendors of Options A, B, and C together with information gathered in
telecons. This enabled the team to develop the 1,000-MT/year process flow diagrams and to
obtain some information on costs.
• Code of Federal Regulation requirements for the construction and operation of a monofill.
• Standard industry sources of cost information such as Perry and Green's Industrial Engineering
Handbook and Richardson Engineering Services' Process Plant Construction Estimating
Standards.
• Telecons with equipment manufacturers.
• Websites of equipment manufacturers.
• The Mercury Management Environmental Impact Statement (MMEIS), published by the Defense
Logistics Agency (DLA 2004). This contains detailed information on storage and transportation
costs.
The SAIC team assigned uncertainty ranges to items that are input to the total cost. The final cost
estimates and uncertainties were estimated by performing an uncertainty analysis using a triangular
probability distributions in Crystal Ball® software (Decisioneering 2004)5. See Section 4.5 for a
discussion of how input ranges of uncertainty were assigned.
S.5 Results
This section considers first the results of the environmental analysis and then the results of the
economic analysis. The results from the environmental evaluation were considered independently from
the economic evaluation (i.e., results from the environmental evaluation had no effect on the economic
evaluation and vice versa). In principal, the economic viability of the various alternatives could have
been considered as one of the top-level criteria in the AHP analysis, but this was not part of the scope of
Crystal Ball®) is user-friendly software that facilitiates the performance of Monte Carlo-type analyses by linking to data in
Excel spreadsheets.
S-4
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Mercury Environmental and Economic Study Final Report April 2005
the present analysis. An example of an AHP study in which both economic and environmental factors
were considered can be found in USEPA (2002c).
S.5.1 Environmental Analysis - Results
Table S-l shows the results for the twelve treatment and disposal alternatives (independent of mass).
The AHP process scales all values to 100 percent. Thus the more alternatives analyzed the smaller the
values for each alternative. The values in Table S-l should be considered as being relative to each other,
not as absolutes. The values in Table S-l are normalized to 1000 points to make them whole numbers.
The following are some observations derived from Table S-l:
• In general, mobile treatment alternatives score better than centralized treatment alternatives.
The principal reason for this is that the authors made a simplifying assumption: for the
centralized treatment alternatives, elemental mercury is transported to the central treatment
unit, whereas the mobile treatment facility travels to the elemental mercury, in which case
only the waste product is transported. In Section S.3, the transportation criterion (C.3) is
assigned a weight of 0.216, with only the monofill being of greater concern. See Figure S-l
for the relative importance of each criteria and subcriteria. Of the transportation subcriteria,
accidental mercury releases are assigned by far the greatest weight (0.747) so that alternatives
in which mercury can be released during transportation have a relatively large unfavorable
impact on the total score. Data and assumptions used by DLA (2004) were used to assess
risks from mercury transport; these data are in Appendix A.
• There is a slight preference towards macroencapsulation alternatives over alternatives that do
not include this additional treatment. This is principally because the polyethylene-
macroencapsulated waste is expected to behave relatively well in the monofill and decrease
the potential long-term leachability of mercury.
• All of the alternatives that include Option B technology score higher than options which
include Option C technology. This is because the Option B waste form has a lower leaching
rate in the monofill than does the Option C waste form (see Figure B-l in Appendix B) and
the Option B leaching rate is much less sensitive to changes in pH than is Options C. In
addition, currently available data on the Option C technology suggest a relative high rate of
volatilization of mercury, which in itself could present a release pathway and could also lead
to decreased effectiveness (through deformation) of the encapsulation material over time
(discussed in Appendix B).
• Cases which include Option A technology are more scattered; one Option A case scores
highest while a different Option A case scores lowest. The Option A cases without
macroencapsulation tend to score low because available data (see Figure B-l in Appendix B)
suggest that leaching rates from the Option A waste form are quite sensitive to small changes
in pH. This conclusion should be caveated by noting that there are large uncertainties in the
leaching results presented on Figure B-l.
The above observations were confirmed by performing analyses that addressed uncertainties by
changing the intensities assigned to the various options. For example, changing the intensities of the four
Option C cases to reflect relatively good environmental performance in the monofill considerably
increased their scores and improved their ranking. In addition, the authors conducted a selection of
sensitivity analyses on the relative importance of the criteria, as follows:
• Changing the weight of the final disposal criterion from 49.3% to 75% (i.e., more important)
• Changing the weight of the final disposal criterion from 49.3% to 25% (i.e., less important)
• Changing the weight of the transportation criterion from 21.6% to 40% (i.e., more important)
• Changing the weight of the transportation criterion from 21.6% to 10% (i.e., less important)
S-5
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Mercury Environmental and Economic Study Final Report April 2005
• Changing the weight of the abnormal/ accidental operations criterion from 18.8% to 40%
(i.e., more important)
• Changing the weight of the abnormal/ accidental operations criterion from 18.8% to 10%
(i.e., less important)
• Changing the weight of the routine operations criterion from 6.5% to 13% (i.e., more
important)
• Changing the weight of the routine operations criterion from 6.5% to 3.2% (i.e., less
important)
• Changing the weight of the decommissioning criterion from 3.8% to 7.6% (i.e., more
important)
• Changing the weight of the decommissioning criterion from 3.8% to 1.8% (i.e., less
important)
In each case the weights of the remaining criteria were changed (while keeping their relative
magnitudes the same) to ensure that the sum of all the weights is 100%. The results of the analyses of
the three most sensitive criteria, which are the first six bullets listed above, are shown in Table S-2. The
remaining sensitivities are presented in Appendix A and are not presented here because they produce very
small differences in the scores.
In all cases, the same two alternatives remain the most highly ranked for both the baseline analysis
and the ten sensitivity analyses (i.e., Option A and Option B with mobile treatment and
macroencapsulation). At the other extreme, the same single alternative remained the most unfavorably
ranked in all cases (i.e., Option A with centralized treatment and no macroencapsulation). In between,
there are minor changes in ranking. This helps show the stability in the results.
In addition to sensitivity analyses, the Team also performed uncertainty analyses. Uncertainty
identifies the extent to which variation in the information and data influences the conclusions. Some of
the areas of uncertainty include the following (see Appendix B):
• Monofill Disposal Stability for Option C- long term: Conflicting data are available regarding
the degree of mercury vapor generation from the Option C process, which is an area of
uncertainty affecting stability. Table S-3 shows that, if the long-term behavior of Option C-
generated waste in the monofill is better than assumed in the base case, its ranking improves
considerably. This issue is discussed in more detail in Section 3.8.
• Monofill Disposal Stability for Option A: As discussed above, a single alternative scored
lowest in all sensitivity analyses (i.e., centralized treatment of Option A with no
macroencapsulation). As an uncertainty analysis, intensity values of this alternative were
changed to demonstrate how its score may rise, as follows:
Option A + no macroencapsulation + centralized treatment. Original score 48 (12th
highest)
Analysis 1: Changing intensity of <40 year disposal condition from 'moderate' to
'low': slight increase in score to 55 (12th highest)
Analysis 2: Changing intensity of >40 year disposal condition from 'moderate' to
'low': significant increase in score to 84 (6th highest)
Analysis 3: Changing intensity of both the <40 year and >40 year disposal condition
from 'moderate' to 'low': significant increase in score to 92 (4th highest)
This illustrates that consideration of sensitivities and uncertainties must be an important factor in
decision-making. The recommendations below include one that addresses the desirability of obtaining
better leaching data before making final choices between alternatives.
S-6
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Mercury Environmental and Economic Study Final Report April 2005
• Other Monofill Disposal Stability: An obvious area of uncertainty for all alternatives is the
degree to which the disposal conditions will remain stable for both a short and a long period
of time (less than 40 years and greater than 40 years, respectively). This range was
demonstrated for one of the alternatives. In addition, the scale-up performance of the
treatment technologies themselves is uncertain with regard to their ability to treat relatively
large quantities of mercury for an extended period of time. In all cases, good mixing and
operational consistency are expected to be critical in achieving long-term stability.
• Accidental Releases of Mercury During Operations: Risks of accidental releases of mercury
during the mercury treatment step may be higher or lower than evaluated. This range was
demonstrated for two of the alternatives.
The uncertainty analyses and results are described in Table S-3. Each row of the table represents an
instance where data are changed for just one of the alternatives. As shown, a total of 11 different
uncertainty analyses were conducted.
The 11 sets of uncertainty analysis results in Table S-3 show how the overall ranking of each
alternative is affected as the intensities of individual criteria are changed. It would be expected that the
largest changes in ranking would result from changing the subcriteria with the largest relative weights,
i.e., the weight of the subcriteria times the weight of the criteria. As seen from Figure S-l long-term
disposal subcriteria has the largest relative weight.
As would be expected if the model worked properly, the uncertainty analyses showed that results
change most significantly in the case of changing the intensity of the long term (>40 year) disposal
criterion between 'Moderate' and 'Low.' This is shown for Reference Nos. 1 through 7. For example, as
discussed above, the lowest-scored Option A alternative in Table 3-4 (Reference No. 3) significantly
improves its score, from 48 (12th best) to 84 (6th best). Changes in the intensity of the shorter term (<40
year) value also improve the score, but not as much (Reference Nos. 2 and 4).
Uncertainty with regard to accidental releases (mercury spills) during operations have a relatively
small effect on results. For example, an Option B alternative (Reference Nos. 8 and 9) still ranks high
regardless of whether the intensity is given a value of low, moderate, or high.
The uncertainty analysis can be used to identify important parameters in which further research may
be required. That is, particular attention could be placed on uncertain data, which significantly affect the
results. As shown above, this suggests that uncertainty with regard to long-term storage and disposal
represents one such parameter.
S.5.2 Economic Analysis - Results
The results of the economic analysis are shown in Tables S-4 and S-5. The results are presented as
Net Present Values (NPV), for which the team used the OMB 30-year real discount rate of 3.5% per year.
Note that the "best" estimates are the means that result from the Monte Carlo analysis and are not
necessarily exactly the same as would result from a sum of point estimates without uncertainty
distributions. Tables S-4 and S-5 prompt a number of observations and conclusions.
• The most striking result is that the Option C cases cost far more than do the others. Analysis
of the calculations reveals that there is one parameter that drives almost the whole of this
difference - the cost of reagents. The cost was provided by the vendor for the amalgamation
and stabilization of elemental mercury. No attempt was made to adjust it for potential
economies of scale. The actual cost of reagents for the Option C process is proprietary and
cannot be quoted here but calculations show that the NPV for Option C reagent costs alone
for the 5,000 MT case is approximately $123M. For Option A the comparable costs are
approximately $8M and for Option B approximately $3.4M. Therefore, for the alternatives
that treat 5,OOOMT, the reagent costs alone account for more than $100M difference between
S-7
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Mercury Environmental and Economic Study Final Report April 2005
the costs of Option C process and those of the Option A or Option B processes, with
correspondingly larger differences for the 12,000 MT and 25,000 MT alternatives.
• As noted, the composition of the Option C reagents is proprietary. In any future decision
making process, the cost per kg of treated Hg will need to be examined in more detail.
• The Option B process consistently exhibits the lowest costs. As noted above, it has the
lowest reagent cost. In addition, it has the least mass increase of the three technologies - the
mass multipliers for waste form production are 1.63 (Option B), 3.26 (Option A), and 5.66
(Option C)6. This affects other items such as transportation costs.
• The best estimates for the NPV of alternatives that include mobile treatment are somewhat
higher than those for alternatives that include treatment at fixed facilities. In addition, the
uncertainty ranges are much wider. Both of these principally result from the wide uncertainty
bands assigned to mobile treatment alternatives -20% to +200% for capital costs and -50%
to + 100% for O&M costs. These wide ranges were assigned because the mobile treatment
option is not well defined (e.g., the number of treatment units is not known). There are also
extra costs associated with assembling and disassembling the equipment and moving it from
site to site.
• The cost of storage is relatively modest. Note that these storage costs were derived from data
in the MMEIS. For example, for continued storage of 5,000 MT for 35 years, the NPV is
$ 11.6M. Continuing to store elemental mercury for years or even decades is a reasonable
course of action.
S.6 Conclusions and Recommendations
• One key reason why the Option C process alternatives fall in the bottom half of Table S-l is
that the team assigned considerable importance to what is known about mercury vapor
evolution from the Option C waste form. However, the data in this area are not of high
quality and further research is needed to confirm that this relatively unfavorable weighting of
the Option C process is justified.
• The data on leaching performance as a function of pH strongly favor Option B (see Figure B-
1 in Appendix B). There is considerable scatter in the leaching data for the other two
processes. Further research in this area could help to provide greater confidence in the
stability of waste forms in typical monofill environments.
• The effectiveness of macroencapsulation in the long term is uncertain. Further assessment of
the long-term effectiveness of macroencapsulation would be valuable.
• As noted above, the predicted cost of the Option C cases is much greater than those of the
other two processes. A large portion of this difference can be attributed to reagent costs. It
would be useful to perform an investigation to see whether the Option C process can be run
with a cheaper mix of reagents, or whether economies of scale might lead to reduced costs in
this area. Since the mix of reagents in the Option C process is proprietary (but not in the
other two cases) it was not possible to perform any further analyses in the course of this
project.
• The Option B process consistently exhibits the lowest costs. As noted above, it has the
lowest reagent cost. In addition, it has the least mass increase of the three technologies. This
affects other items such as transportation costs.
• The best estimates for the NPV of alternatives that include mobile treatment are somewhat
higher than those for alternatives that include treatment at fixed facilities. In addition, the
uncertainty ranges are much wider. Both of these principally result from the wide uncertainty
bands on mobile treatment alternatives -20% to +200% for capital costs and -50% to + 100%
6 See Sections 4.1.2.1, 4.1.2.2, and 4.1.2.3 for discussion of these multipliers.
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Mercury Environmental and Economic Study Final Report April 2005
for O&M costs. There are also extra costs associated with assembling and disassembling the
equipment and moving it from site to site. The mobile treatment alternative needs to be much
better defined if the uncertainty bands are to be reduced.
The storage alternatives are reasonably economical and, as shown in the previous report
EPA/600/R-03/048 do not pose large environmental risks. It would still be cost effective to
continue to store elemental mercury for a number of years or decades in anticipation that
there might be a breakthrough in treatment technologies.
S-9
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Mercury Environmental and Economic Study
Final Report April 2005
Table S-l. Environmental Analysis - Summary of Baseline Results for 12 Evaluated Alternatives
Treatment Scenario
Treatment Process
Option A
Option B
Option B
Option A
Option B
Option B
Option C
Option C
Option A
Option C
Option C
Option A
Macro-
Encapsulation
With
With
Without
With
With
Without
Without
With
Without
Without
With
Without
Fixed or Mobile
Facility
Mobile
Mobile
Mobile
Fixed
Fixed
Fixed
Mobile
Mobile
Mobile
Fixed
Fixed
Fixed
Number of alternatives evaluated
Total
Average score (total divided by 12, the number of alternatives)
Overall Ranking
Score
(as fraction of 1,000)
117
117
108
98
98
89
73
73
66
57
57
48
12
1,000
83
Rank
(Best to Worst)
1
1
3
4
4
6
7
7
9
10
10
12
—
—
—
Shading indicates the highest-ranking alternatives.
Distributive mode; overall inconsistency factor from Expert Choice software: 0.02 (good).
Average value is provided for reference and identifies the average score for the twelve evaluated technologies.
S-10
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Mercury Environmental and Economic Study
Final Report April 2005
Table S-2. Environmental Sensitivity Analysis
Treatment Scenario
Treatment
Process
Option A
Option B
Option B
Option A
Option B
Option B
Option C
Option C
Option A
Option C
Option C
Option A
Macro-
Encapsul
ation
With
With
Without
With
With
Without
Without
With
Without
Without
With
Without
Fixed or
Mobile
Facility
Mobile
Mobile
Mobile
Fixed
Fixed
Fixed
Mobile
Mobile
Mobile
Fixed
Fixed
Fixed
Average
Total
Ranking3
Baseline (from
Table S-l)
Score
117
117
108
98
98
89
73
73
66
57
57
48
83
1,000
Rank
1
1
3
4
4
6
7
7
9
10
10
12
—
—
Importance on Disposal
Sensit
Hi
Score
124
124
111
115
115
102
60
60
48
52
52
39
83
1,000
ivity:
gh
Rank
1
1
5
3
3
6
7
7
11
9
9
12
—
—
Sensitivity:
Low
Score
110
110
105
82
82
78
85
86
84
61
61
56
83
1,000
Rank
1
1
3
7
7
9
5
4
6
10
10
12
—
—
Importance on Transport
Sensitivity:
High
Score
120
120
113
85
85
79
84
85
81
52
52
47
83
1,000
Rank
1
1
3
4
4
9
7
4
8
10
10
12
—
—
Sensitivity:
Low
Score
115
115
105
106
106
96
66
66
57
60
60
48
83
1,000
Rank
1
1
5
3
3
6
7
7
11
9
9
12
—
—
Importance on Accidents
Sensitivity:
High
Score
108
108
101
94
94
88
76
76
71
64
64
57
83
1,000
Rank
1
1
3
4
4
6
7
7
9
10
10
12
—
—
Sensitivity:
Low
Score
120
120
110
100
100
90
72
72
64
54
54
44
83
1,000
Rank
1
1
3
4
4
6
7
7
9
10
10
12
—
—
Shading indicates the highest-ranking alternatives. In the sensitivity analysis for each criterion, the importance of the criterion is set at higher or lower than its baseline value, as
identified in the text. The four other criteria comprise the remainder, proportional to their original contributions.
a. Scores normalized to total 1,000.
S-ll
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Mercury Environmental and Economic Study
Final Report April 2005
Table S-3. Uncertainty Analysis for Mercury Management Alternatives
Ref.
No.
0
1
2
3
4
5
6
7
8
9
10
11
Alternative
All
Treatment
Process
Option C
Option C
Option C
Option C
Option A
Option B
Option B
Option C
Macro-
Encapsulat
ion
Without
With
Without
With
Without
With
Without
With
Fixed or
Mobile
Facility
Mobile
Mobile
Fixed
Fixed
Fixed
Mobile
Mobile
Fixed
Criteria
Change in Intensity for Uncertainty
Analysis
Baseline
Change
Baseline for comparison: Same results as Table S-2
Monofill Disposal,
>40 years
Monofill Disposal,
<40 years
Monofill Disposal,
>40 years
Monofill Disposal,
both <40 years and
>40 years
Monofill Disposal,
<40 years
Monofill Disposal,
>40 years
Monofill Disposal,
both <40 years and
>40 years
Accidental Releases
(Mercury Spills)
Moderate
Moderate
Moderate
Moderate
Low
Low
Low
Moderate
Moderate
Low
Low
Low
Low
Moderate
Moderate
Moderate
Low
High
Low
High
Initial Result
(Table S-l)
Score
—
73
73
57
57
48
117
108
57
Rank
—
7
8
10
11
12
2
3
11
Uncertainty
Analysis Result
Score
—
99
99
82
82
55
84
92
108
76
68
117
102
66
51
Rank
—
o
J
o
J
6
6
12
6
4
2
6
9
1
3
9
11
S-12
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Mercury Environmental and Economic Study
Final Report April 2005
Table S-4. Net Present Value Estimates
Treatment Scenario
Treatment
Process
Option A
Option A
Option A
Option A
Option B
Option B
Option B
Option B
Option C
Option C
Option C
Option C
Macro-
Encapsulation
With
With
Without
Without
With
With
Without
Without
With
With
Without
Without
Fixed or
Mobile
Facility
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Long-Term Storage*6
Net Present Value Estimates in Millions of Dollars
5,000 Metric Tons
Min.a
77.1
75.8
60.2
57.7
32.3
32.4
22.7
22.3
162
138
146
119
10.4
Bestb
82.7
99.2
65.4
79.8
34.3
40.9
24.3
29.3
178
203
163
184
11.6
Max.c
89.0
128
71.3
107
36.4
50.7
26.2
38.0
197
292
181
270
12.8
12,000 Metric Tons
Min.a
149
143
117
105
62.2
60.5
42.8
40.9
342
290
306
247
26.1
Bestb
161
191
128
150
66.2
78.3
46.1
54.2
378
429
341
386
29.0
Max.c
174
251
141
207
70.6
97.5
49.9
71.7
418
617
381
573
31.9
25,000 Metric Tons
Min.a
245
232
184
169
102
98.4
69.6
65.1
579
490
517
421
51.3
Bestb
265
315
203
242
109
127
75.2
87.5
639
732
578
656
57.0
Max.c
287
415
224
341
116
160
81.8
118
707
1,040
647
967
62.7
a. Fifth percentile of the distribution derived from the Crystal Ball® analysis.
b. Mean of the distribution derived from the Crystal Ball® analysis.
c. Ninety fifth percentile of the distribution derived from the Crystal Ball® analysis.
d. Not derived from Crystal Ball® analysis - best estimate based on MMEIS data (DLA 2004) with ±10% uncertainties.
e. Cost of shipping elemental mercury to the storage location not included. Upper bound transportation costs derived from MMEIS data are $0 (5,000 MT), $1.0M( 12,000 MT), and
S2.3M (25,000 MT). These are at most small percentages of the total cost of long-term storage.
S-13
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Mercury Environmental and Economic Study
Final Report April 2005
Table S-5. Net Present Value Estimates Expressed as Cost per Metric Ton of Treated Mercury
Treatment Scenario
Treatment
Process
Option A
Option A
Option A
Option A
Option B
Option B
Option B
Option B
Option C
Option C
Option C
Option C
Macro-
Encapsulation
With
With
Without
Without
With
With
Without
Without
With
With
Without
Without
Fixed or
Mobile
Facility
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Long-Term Storage
Net Present Value Estimates in Dollars
5,000 Metric Tons
Min.
15,400
15,200
12,000
11,600
6,500
6,500
4,500
4,500
32,400
27,600
29,200
23,800
2,100
Best
16,600
19,800
13,100
16,000
6,900
8,200
4,900
5,900
35,600
40,600
32,600
36,800
2,300
Max.
17,800
25,600
14,300
21,400
7,200
10,100
5,200
7,600
39,400
58,400
36,200
54,000
2,600
12,000 Metric Tons
Min.
12,400
11,900
9,800
8,800
5,000
5,100
3,600
3,400
28,500
24,200
25,500
20,600
2,200
Best
13,400
15,900
10,700
12,500
5,500
6,500
3,800
4,500
31,500
35,800
28,400
32,200
2,400
Max.
14,500
20,900
11,800
17,300
5,900
8,100
4,200
6,000
34,800
51,400
31,800
47,800
2,700
25,000 Metric Tons
Min.
9,800
9,300
7,400
6,800
4,100
3,900
2,800
2,600
23,000
19,600
20,700
16,800
2,100
Best
10,600
12,600
8,100
9,700
4,400
5,100
3,000
3,500
25,600
29,300
23,100
26,200
2,300
Max.
11,500
16,600
9,000
13,600
4,600
6,400
3,300
4,700
28,300
41,600
25,900
38,900
2,500
S-14
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Mercury Environmental and Economic Study
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Figure S-l. AHC Criteria and Subcriteria Relative Weights
5 -
4 -
o
X
4-1
.E
O)
1
- >40 yr
Reagent to
- Treat
Monofill
. Non-Hg
Spill
-Hg Spill
~Atm Disch
Non Product
~~ Solid
Decom
C5 Storage
C3 Transportation C2 Abnormal Operations C1 Routine Operations C4 Decommissioning
Primary Criteria
S-15
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Mercury Environmental and Economic Study Final Report April 2005
1.0 INTRODUCTION
This section provides background on the need for the long-term disposal of elemental mercury and
discusses the outline of the remainder of this report.
1.1 Background
The use of mercury in products and processes is decreasing. It is likely that in the future, the supply of
mercury will far exceed the demand for mercury. In addition, the Department of Defense (DOD) has
stockpiled more than 4,800 tons of mercury that are no longer needed, and the Department of Energy
(DOE) has also accumulated large volumes of elemental mercury. Therefore, strategies must be devised
for managing the excess mercury. Currently, the most prevalent method is to store the elemental, liquid
form in flasks and stockpile them in warehouses. The risks associated with this method of storing
elemental mercury have been extensively discussed in the Final Mercury Management Environmental
Impact Statement (DLA 2004).
Independently of DLA, EPA's Offices of Research and Development (ORD) and Solid Waste (OSW)
have been working with DOE to evaluate technologies for permanently stabilizing and disposing of
wastes containing mercury (DOE 1999a-1999e; USEPA 2001, 2002a,b). Other comprehensive studies
carried out in the recent past include one by SENES Consultants (SENES 2001) who produced a draft
report for Environment Canada evaluating 67 technologies for the retirement and long-term storage of
mercury. In addition, OSW is considering revisions to the Land Disposal Restrictions (LDRs) for
mercury. Land disposal of hazardous wastes containing greater than 260 mg/kg mercury is currently
prohibited. For several years OSW has pursued options which would allow land disposal of waste
containing greater than 260 mg/kg mercury. These actions include the following:
• Land Disposal Restrictions: Treatment Standards for Mercury-Bearing Hazardous Waste. Notice
of Data Availability. Federal Register January 29, 2003 (Volume 68, Page 4481). Presents OSW
studies regarding the treatment of elemental mercury and wastes with >260 mg/kg mercury. EPA
additionally concludes that changes to national regulations are impractical at this time.
• Hazardous Waste Management System; Identification and Listing of Hazardous Waste;
Chlorinated Aliphatics Production Wastes; Land Disposal Restrictions for Newly Identified
Wastes; and CERCLA Hazardous Substance Designation and Reportable Quantities. Proposed
Rule. Federal Register August 25, 1999 (Volume 64, page 46521). EPA proposed, as an option,
an alternative treatment standard for a hazardous waste containing >260 mg/kg mercury which
would allow land disposal under certain disposal conditions. This alternative was not ultimately
adopted.
• Potential Revisions to the Land Disposal Restrictions Mercury Treatment Standards. Advance
notice of proposed rulemaking (ANPRM). Federal Register May 28, 1999 (Volume 64, Pages
28949-28963). This notice presents options, issues, and data relevant to potential revised
mercury treatment standards.
At this time, however, no specific revisions to the LDRs for mercury-containing wastes are
forthcoming.
Using the above-referenced work as a starting point, EPA prepared report EPA/600/R-03/048,
Preliminary Analysis of Alternatives for the Long-Term Management of Excess Mercury (USEPA
2002c). In this report, EPA evaluated two types of treatment technologies: sulfide/amalgamation (S/A)
techniques and the mercury selenide treatment process. The S/A techniques were represented by: a)
DeHg® amalgamation; b) the Sulfur Polymer Solidification/Stabilization (SPSS) process; and c) the
Perma-Fix sulfide process. These were grouped as a single class because they have very similar
characteristics when compared against the criteria defined by the team (comprised of SAIC staff) and
modeled in a computer program that uses the Analytic Hierarchy Process (AHP) as an aid to decision
1-1
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Mercury Environmental and Economic Study Final Report April 2005
making, Expert Choice. Therefore, only these two general types of treatment technologies were
evaluated. These were combined with four disposal options: a) disposal in a RCRA-permitted landfill; b)
disposal in a RCRA-permitted monofill; c) disposal in an engineered belowground structure; and d)
disposal in a mined cavity. In addition, there were three storage alternatives for elemental mercury: a)
storage in an aboveground RCRA- permitted facility; b) storage in a hardened RCRA-permitted structure;
and c) storage in a mined cavity.
The purpose of the present work is the logical next step, which is to focus on just a few of the
alternatives considered above. This allows a more detailed breakdown and analysis of the
stabilization/amalgamation alternatives than was possible in EPA/600/R-03/048, and also allows more
effort to be applied to developing cost information.
1.2 Scope of Work
The scope of work requested by EPA was to provide an economic and environmental analysis of the
following:
Three treatment technologies, identified as Options A, B, and C to protect certain proprietary
information
• Two macroencapsulation alternatives:
a. Dispose of the treated mercury with macroencapsulation, and
b. Dispose of the treated mercury without macroencapsulation.
• The alternatives are further divided as follows:
i. Build a fixed treatment facility at one site to which all of the bulk elemental mercury is
transported and dispose of in a collocated monofill, or
ii. Build a portable waste treatment facility and take it to the sites at which the bulk elemental
mercury is stored. Dispose of the treated waste in a centralized monofill.
Combining all the cases above gives 12 alternatives for treatment and disposal7. The work includes
performing an environmental comparison of these twelve alternatives.
The final part of the work is to develop Life Cycle Cost Estimates (LCCEs)8 for the foregoing 12
alternatives and the further alternative of storing bulk elemental mercury in an aboveground structure,
making 13 alternatives in all. For each of these combinations, SAIC considered alternatives that will
treat; a) 5,000 MT; b) 12,000 MT; and c) 25,000 MT of elemental mercury9. This gives 39 alternatives
for economic analysis.
The authors aware that there are more alternatives than this (e.g., transportation from the centralized treatment site to a remote
monofill). However, the authors believe that the extra insights to be gained would not be worth the effort required to keep
track of the proliferating alternatives this would generate.
8 A lifecycle cost estimate is one that provides costs for all elements of a project's lifetime, including preliminary design, final
design, startup, operation, and decommissioning.
9 The basis for selecting 5,000 MT, 12,000 MT, and 25,000 MT was initially that these are multiples of the DLA stockpile
numbers. Later EPA analysis (Randall 2005) estimated the quantity of mercury contained in chlor-alkali cells in the US and
Western Europe as about 15,000 MT with another 10,000-12,000 MT in the rest of the world. Although opinion varies widely
as to the rate at which these cells will close, there is good reason to believe that enough plants will close world-wide within the
next 15-20 years to overwhelm dwindling world demand for mercury, thereby posing a question as to its environmentally
appropriate disposition.
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1.3 Approach
There are three major parts to the required analysis:
• Choice of the three treatment technologies
• Environmental analysis
• Economic analysis
1.3.1 Choice of Three Technologies
The first step was to review the available literature and to hold consultations with EPA personnel in
ORD and OSW. This resulted in a short-list of 6 technologies, identified as Options A through F. The
references used in this analysis are provided in Section 5.2.
The list was then winnowed down to 3 technologies by using the Kepner-Tregoe decision-making
method as a tool. This method is described in Section 2. It essentially involves:
• Developing a list of criteria against which the technologies are ranked
• Assigning a weight to each criterion, on a scale from 1-10, with 10 indicating that the criterion is
extremely important and 1 indicating that the criterion is unimportant
• Scoring each technology against each criterion, again on a scale from 1-10, with 10 indicating
that the technology performs well against the criterion and 1 indicating that it performs poorly
• For each technology, multiplying the score against a criterion by the weight of that criterion and
summing over all criteria. The sums then provide a ranking for the criteria that allows the top 3
to be chosen.
1.3.2 Environmental Analysis
The method chosen for the environmental comparison of the twelve treatment and disposal
alternatives is the Analytic Hierarchy Procedure (AHP) as embodied in the Expert Choice software. AHP
was developed at the Wharton School of Business by Dr. Thomas Saaty and continues to be a highly
regarded and widely used decision-making tool. The AHP engages decision-makers in breaking down a
decision into smaller parts, proceeding from the goal to criteria to sub-criteria down to the alternative
courses of action. Decision-makers then make simple pairwise comparison judgments throughout the
hierarchy to arrive at overall priorities for the alternatives. The decision problem may involve social,
political, technical, and economic factors. The AHP helps people cope with the intuitive, the rational and
the irrational, and with risk and uncertainty in complex situations. It can be used to: predict likely
outcomes, plan projected and desired futures, facilitate group decision making, exercise control over
changes in the decision making system, allocate resources, select alternatives, and do cost/benefit
comparisons.
The Expert Choice software package incorporates the principles of AHP in an intuitive, graphically
based and structured manner so as to be valuable for conceptual and analytical thinkers, novices and
subject matter experts. Because the criteria are presented in a hierarchical structure, decision-makers are
able drill down to their level of expertise, and apply judgments to the criteria deemed important to their
objectives. At the end of the process, decision-makers are fully cognizant of how and why the decision
was made, with results that are meaningful and actionable.
In summary, Expert Choice was chosen for the present work for the following reasons:
• It is based on the well-established and widely-used Analytic Hierarchy Process
• It allows the user to incorporate both data and qualitative judgments
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• It can be used even in the presence of uncertainties, because it allows users to make subjective
judgments
• Once the basic model for a particular decision has been set up, it is easy to perform sensitivity
studies
• The model can readily be adjusted as better data become available, or if more alternatives need to
be added
The environmental comparison is described in Section 3. Appendix A contains information on the
AHP and on how the inputs to the Expert Choice software were specifically developed for the present
work. Appendix B contains further detail on the use of the AHP.
1.3.3 Economic Analysis
As described above, 36 treatment and disposal alternatives are being considered. In addition, cost
estimates have been prepared for storage of the three masses of elemental mercury in aboveground
facilities, making a total of 39 cost estimates in all.
The thirty-six cost estimates (based on the Process Flow Diagrams) for treatment and disposal
includes the following elements10:
• Capital costs for the treatment facility,
• Capital costs for the macroencapsulation facility (if part of the alternative),
• Operating and maintenance costs for the treatment process,
• Operating and maintenance costs for the macroencapsulation process (if part of the
alternative),
• Costs associated with the mobile treatment alternatives,
• Transportation costs associated with each alternative,
• Costs of storing elemental mercury prior to treatment,
• Decommissioning costs for the treatment facilities,
• Monofill engineering and construction costs,
• Monofill operating costs, and
• Costs of maintaining and monitoring the monofill for a thirty-year period following its
closure.
Each of the three storage alternatives contains the costs of maintaining the existing stockpile
(assumed to be 5,000 MT) in storage, adding to storage space as necessary, and transporting elemental
mercury to the storage facility(ies).
The SAIC team developed process flow diagrams for each of the three treatment technologies and the
associated macroencapsulation process and a preliminary design for the monofill such that 1,000 MT of
elemental mercury will be treated and disposed of each year.
The sources of information for the cost estimates included:
• Published work by the vendors of the three treatment options together with information
gathered in telecons. This enabled the team to develop the 1000-MT/year process flow
diagrams and to obtain some information on costs.
• Code of Federal Regulation requirements for the construction and operation of a monofill.
10 Note that these cost do not contain any contingency for the occurrence of accidents or malfunctions (e.g., spillage of elemental
mercury during transportation or remediation of excessive leakage from a monofill).
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• Standard industry sources of cost information such as Perry and Green's Industrial
Engineering Handbook and Richardson Engineering Services' Process Plant Construction
Estimating Standards.
• Telecons with equipment manufacturers.
• Websites of equipment manufacturers.
• The Mercury Management Environmental Impact Statement (MMEIS), published by the
Defense Logistics Agency (DLA). This contains detailed information on storage and
transportation costs.
The SAIC team assigned uncertainty ranges to items that are input to the total cost. The final cost
estimates and uncertainties were estimated by performing an uncertainty analysis using Crystal Ball®
software (Decisioneering 2004).
The economic and uncertainty analyses are described in Chapter 4. Appendices C-G provide further
detail about cost imputs.
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2.0 SELECTION OF TECHNOLOGIES FOR EVALUATION
The contract with EPA required SAIC to consider three different chemical treatment alternatives.
The purpose of this chapter is to show how the three alternatives were selected. The chapter describes
criteria that were used for this purpose. These criteria were discussed with EPA and represent a
consensus.
2.1 Criteria for Selection of Technologies
In the previous project for EPA ORD (Preliminary Analysis of Alternatives for the Long-Term
Management of Excess Mercury - USEPA 2002c), criteria were developed when evaluating each potential
management alternative (consisting of a treatment technology followed by a disposal method). These
criteria included costs, risks, environmental performance, state of maturity, and other factors. The cost
criteria and non-cost criteria were given equal importance in the 2002 analysis. Subcriteria were given
varying weights based on the evaluation team's consensus. The complete list of criteria used is given in
Table 2-1. This list from the 2002 project proved useful as a starting point for identifying important
issues for the present project.
Table 2-1. Criteria Chosen for the AHP Analysis in Preliminary Analysis of Alternatives for the
Long-Term Management of Excess Mercury, August 2002.
Non-cost Criteria (0.5)*
o Compliance with Current Laws and Regulations (0.045)
o Implementation Considerations (0.154)
• Volume of waste (0.143)
• Engineering requirements (0.857)
o Maturity of the Technology (0.047)
• State of maturity of the treatment technology (0.500)
• Expected reliability of the treatment technology (0.500)
o Risks (0.312)
• Public risk (0.157)
• Worker risk (0.594)
• Susceptibility to terrorism/sabotage (0.249)
o Environmental Performance (0.336)
• Discharges during treatment (0.064)
• Degree of performance testing of the treatment technology (0.122)
• Stability of conditions in the long term (0.544)
• Ability to monitor (0.271)
o Public Perception (0.107)
Cost Criteria (0.5)
o Implementation costs (0.5)
o Operating costs (0.5)
* The figures in parentheses give the weights assigned to each of the criteria and sub-criteria
using the process ofpairwise comparison that is at the core of the Analytic Hierarchy Process
(AHP). At each level, the weights are determined independently and add to one. Higher weights
indicate greater importance.
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2.1.1 Identifying Critical Issues
This chapter focuses on the treatment technology step only, prior to further encapsulation and
placement of the treated elemental mercury in a monofill. The critical environmental pathway that was
evaluated is mercury leaching following disposal. The purpose of the selection process is to identify
technologies for further study. Therefore the developed criteria are at a screening level, allowing for
more detailed review later in the process.
The proposed issues are presented in Table 2-2. The following six issues are identified:
1. Appropriateness of technology for the treatment of elemental mercury
2. Type of leaching performance data
3. Results of leaching performance tests
4. Extent of environmental and cost information
5. Costs and Complexity
6. Development
Each of these issues is assigned a weighting factor of between 1 and 10 to account for its perceived
importance. Table 2-2 provides the consensus suggestions for these weighting factors. The first three
issues are assigned a weighting factor of 10, reflecting the team's view that the ability to treat elemental
mercury with the end product having satisfactory leaching performance is the primary objective of the
technology. Having adequate information about environmental performance and costs is deemed
relatively important (a weight of 8), otherwise it is hard to perform a credible analysis of the technology.
Finally, expected costs and the current state of development are deemed somewhat less important because
these issues can potentially be worked on and improved over time.
2.1.2 Evaluation of the Technologies
One important aspect of the evaluation is to identify any 'pass/ fail' criteria for a particular issue. For
example, if a particular technology fails to meet some minimum criterion, then the technology would be
dropped from consideration. An example of such a criterion is included in the first row of Table 2-2,
where the technologies, at a minimum, should at least in theory be capable of treating elemental mercury.
An additional aspect is the effectiveness with which each technology addresses each issue. This
aspect is addressed by providing a score, as is laid out in Table 2-2. Like the issue weighting factors, the
score ranges from 1 - 10.:: For each issue, the score for a particular technology is multiplied by the
weight. This product is then summed over all issues to give a total score for the technology. This method
of ranking technologies is known as Kepner-Tregoe Decision Analysis.
2.1.3 Identifying Candidate Processes
Many treatment processes are available for reducing the mobility of mercury in various wastes.
However, only a small number of these are expected to be practical for elemental mercury treatment. It is
possible to evaluate any number of candidate treatment processes using the criteria in Table 2-2. To
avoid inefficient research into technologies that are impractical or only marginal in meeting the project
objectives, the following types of technologies were excluded from the evaluation:
• Mercury recovery or extraction technologies, where the intent is to remove or separate the
mercury from a waste for recycling or further treatment
11 For some issues, the scoring process outlined in Table 2-2 allows a score of greater than 10. In this case, the score is capped at
10. Similarly, there is the possibility that some scores can be zero or negative. In this case, the score is not allowed to fall
below 1.
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• Technologies which treat wastewaters or combustion exhaust gases
• Technologies which focus on the treatment of LDR "low mercury" wastes (i.e., less than 260
mg/kg total mercury)
Six technologies were identified as having been used for treating wastes with, at a minimum, percent
levels of mercury. They are identified as Options A through F. References used for this part of the
analysis are listed in Section 5.2.
Any number of additional treatment technologies can in principle be evaluated.
2.2 Scoring Results
The resulting scores for each technology with respect to each criterion are presented in Table 2-3.
The following subsections discuss the information that forms the basis for the scoring results presented in
Table 2-3.
2.2.1 Option A
The Option A process was one of three technologies evaluated by EPA for elemental mercury
treatment, in which leaching was evaluated with respect to pH in oxidizing conditions (see Figure B-l).
Other available data for the treatment performance of elemental mercury includes TCLP and ASTM
testing by the developer of the technology . Several other treatment performance results are available for
mercury wastes, including work in which mercury leaching as a function of pH and liquid-solid ratio was
investigated.
Data are available regarding the formation of mercuric sulfide under long-term conditions; these data
are not specific to any particular technology but can potentially be useful for sulfur-based treatment
processes in general. For example, as discussed in Appendix B, mercuric sulfide (HgS) production may
degrade to from HgS2 anion under alkaline anaerobic conditions. One potential application of the result
is that such conditions would favor the transformation of residual elemental mercury to this stable form.
An alternative application is that in an anaerobic monofill in damp or wet conditions, ionic mercury
(Hg+) and/or ionic mercury bisulfide (HgS2=) may form and result in increased leaching over time.
In the EPA study for elemental mercury treatment, OSW identified highly variable leaching as a
function of pH (as shown in Figure B-l of Appendix B); laboratory quality control checks suggest the
reported data are valid (EPA, 2002b). The results suggest the inherent uncertainties of using a relatively
small set of studies to identify if the observed results represent actual performance of the treatment
process or are a result of heterogeneity in the treated waste, treatment variation, or other factors. This
uncertainty is equally relevant for Technology Options B and C.
The Option A process remains in active development. It has been demonstrated at pilot-scale on liter
quantities of mixed-waste elemental Hg from National Laboratories, and in treatability studies for a major
gold-mining corporation (Randall 2005). After this corporation conducted its own evaluation, it selected
Vendor A for potential treatment of its by-product elemental Hg from foreign mining operations, and has
licensed the technology. There are also plans to build a process facility in Kazakhstan that will treat
elemental mercury and mercury-contaminated soil. Therefore, it appears that technology A is
approaching commercial-scale operation.
2.2.2 Option B
Information available for the Option B process closely parallels that available for Option A. The
treatment of elemental mercury was evaluated by EPA; TCLP testing of treated elemental mercury was
conducted by DOE. In addition, existing general mercuric sulfide formation data can similarly be applied
to the sulfur-based Option B technology.
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USEPA data show a trend in leaching results with respect to pH, with results lowest in acidic
conditions and highest in basic conditions (see Figure B-l). The results were consistently below the UTS
level at all but the highest range of pH.
The Option B process has been used for the treatment of approximately 7600 kg (3.5 tons) of
radioactive elemental mercury since 2001. Therefore the process is in active use and development.
2.2.3 Option C
Information available for the Option C process includes elemental mercury treatment data by USEPA
and DOE TCLP testing of treated elemental mercury. The Option C process was also used for the
experimental treatment of mercury-containing soil in DOE's MER-03 program, where mercury leaching
as a function of pH and liquid-solid ratio was investigated.
The USEPA data shows a trend in leaching results with respect to pH, with the lowest leachable
levels present in basic conditions (see Figure B-l). At pH levels above 6, the mercury solubility was
between the UTS and TC levels.
There is no indication of commercial use beyond bench-scale treatment, although the Option C
process remains in active development/ sponsorship.
2.2.4 Option D
Option D is a selenide process, for which very little environmental data are available.. USEPA
investigated the leaching of mercury selenide with respect to pH and chloride anion concentrations,
although testing was conducted only on a simulated waste treatment residual. The process was developed
for the vapor-phase treatment of elemental mercury generated from lamps, batteries, etc.; it could likely
be adapted to a starting point for elemental mercury.
This process is in commercial use in Europe, making it one of the few treatment processes in use at
larger than bench scale. However, the scale of the equipment is expected to be small relative to the
quantities of mercury present in the DLA stockpile (for example). The process is also relatively complex
due to the high temperatures and continuous processing.
2.2.5 Option E
Option E uses a dithiocarbonate formulation and a small amount of proprietary liquid to produce a
stabilized waste form. This technology has the disadvantage of not having been applied to elemental
mercury. Numerous applications of the technology have been conducted in the DOE MER programs
where percent levels of mercury in wastes were tested. Its potential application to elemental mercury,
therefore, is unknown.
EPA studies have shown that the leachable mercury concentrations were consistently above the UTS
level for most of the pH range. The MER-03 study results are consistent in that the mercury solubility
was found to be lowest at the alkaline pH levels.
The development status of the Option E process is not known.
2.2.6 Option F
Sulfur-impregnated activated carbon has been used for many years in the cleanup of mercury-
contaminated flue gas. However, only limited information is available with regard to how such a material
may treat mercury-containing wastes. Only limited results are available for the testing of a simulated
mercury-contaminated soil. Its potential application towards elemental mercury is unknown.
Available data show a wide range of testing with respect to leaching variables including pH and
chloride content of the leaching solution. In addition, an additional treatment step of cement stabilization
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is conducted following activated carbon treatment in some cases. The leachable mercury concentrations
were consistently below the UTS level for pH 4 and above.
This technology remains in the research stage. However, it is based on the use of readily available
materials. In addition, use/ research for mercury removal from flue gas can be transferred to solid waste
applications.
2.3 Conclusions
The results of the scoring are presented in Table 2-3. Three technologies (Options A, B, and C) have
similar scores. The remaining three technologies (Options D, E, and F) also have similar scores but
significantly lower than the other three technologies. These results support the choice of the Options A,
B, and C processes for more detailed evaluation.
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Table 2-2. Elemental Mercury Treatment Technology Evaluation
Proposed Issue
Weighting Factor
(1-10) for Issue
Proposed Evaluation Criteria and Scores for Each Technology
Minimum
Acceptable
Result (if any)
Appropriateness of
technology for the treatment
of elemental mercury
10
10 - The technology has been tested on elemental mercury (100%)
6 - The technology has been tested on mercury-containing wastes/ soils with percent
levels of elemental mercury
5 - The technology has been tested on mercury-containing wastes/ soils with percent
levels of any form of mercury
1 - The technology has been tested only on low mercury content wastes (e.g., <260
mg/kg)
The technology
should be
applicable to
elemental
mercury
treatment, at
least in theory.
Type of leaching
performance data
10
Points for each of the following (maximum 10 points):
+ 1 point - TCLP (or similar) testing has been conducted
+ 2 points - leaching as a function of pH variation
+ 2 points - leaching as a function of liquid/ solid ratio
+ 2 points - long-term stability testing
+ 2 points - leaching in various oxidation/ reduction conditions
+ 1 point - leaching in the presence of various anions
None
Results of leaching
performance tests
10
Results of leaching performance tests (maximum score 10 points; minimum 1 point):
-2 points to +2 points - Extent to which data trends (if any) are logical, and results for
sample duplicates give reasonable results.
-2 points to +2 points - Extent to which sampling and analysis procedures are well
documented and minimize possible errors
-1 points to + 5 points - For conditions which may be encountered in a monofill (e.g.,
pH), the leaching results are (1) below universal treatment standards (UTS) in most
relevant conditions (+ 5 points); (2) some results are above UTS but still below the TC
(+ 2 points); (3) results are higher than the TC level in critical instances (-1 point).
+ 1 point - Where two or more studies are available, contradictory findings are not
reached.
None
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Table 2-2. Elemental Mercury Treatment Technology Evaluation (continued)
Proposed Issue
Weighting Factor
(1-10) for Issue
Proposed Evaluation Criteria and Scores for Each Technology
Minimum
Acceptable
Result (if any)
Results of leaching
performance tests
10
Results of leaching performance tests (maximum score 10 points; minimum 1 point):
-2 points to +2 points - Extent to which data trends (if any) are logical, and results for
sample duplicates give reasonable results.
-2 points to +2 points - Extent to which sampling and analysis procedures are well
documented and minimize possible errors
-1 points to + 5 points - For conditions which may be encountered in a monofill (e.g.,
pH), the leaching results are (1) below universal treatment standards (UTS) in most
relevant conditions (+ 5 points); (2) some results are above UTS but still below the TC
(+ 2 points); (3) results are higher than the TC level in critical instances (-1 point).
+ 1 point - Where two or more studies are available, contradictory findings are not
reached.
None
Extent of environmental and
cost information
Extent of environmental and cost information (maximum score 10 points):
+ 2 points - Data available from multiple sources (e.g., vendor test, EPA).
+ 2 points - One or more EPA/ DOE test documents (e.g., MER program)
+ 1 point - If not evaluated in the MER program, information is available from the
DLA EIS
+ 2 point - Patents, conference papers, and/or journal articles
+ 1 point - If no patents, etc., then other product literature is available.
+ 2 points - Information on both costs and environmental performance are available
from resources
+ 2 points - Process information is available to verify/ expand the cost data
+ 1 point - General treatment information is available (e.g., sulfide or selenide
chemistry) which is not technology specific, but still useful.
-1 point - Critical information is not in English.
None
Costs and Complexity
10 - Costs and Complexity are expected to be significantly lower than typical (non-
mercury) hazardous waste stabilization/ solidification (S/S) processes
5 - Costs and Complexity are expected to be about the same as typical hazardous waste
S/S processes.
1 - Costs and Complexity are expected to be significantly higher than typical hazardous
waste S/S processes.
None
Level of Development of
Technology
10 - The technology is actively in use for mercury treatment/ disposal at a scale which
would be practical for treating >5,000 tons
5 - The technology remains in the testing/ development stage by a sponsoring
organization
3 - The development status is not known
1 - The technology has been developed but no present sponsor is evident
Must be capable
of commercial
deployment in
the future
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Table 2-3. Elemental Mercury Treatment Technology Evaluation
Proposed Issue
Appropriateness of
technology for the
treatment of elemental
mercury
Availability of leaching
performance data
Results of leaching
performance tests
Extent of environmental
and cost information
Costs and Complexity
Development
Final Score
Weighting
Factor
(WF)
10
10
10
8
5
5
Preliminary Result (score between 1 and 10) for Technology Type; Multiply by Weighting Factor to
Obtain Score for Each Issue
Option A
10 x WF = 100
6 x WF = 60
2 x WF = 20
10xWF = 80
5 x WF = 25
8 x WF = 40
325
Option B
10xWF=100
4 x WF = 40
7 x WF = 70
6 x WF = 48
5 x WF = 25
5 x WF = 25
308
Option C
10 x WF = 100
5 x WF = 50
5 x WF = 50
6 x WF = 48
5 x WF = 25
5xWF = 25
298
Option D
9 x WF = 90
3 x WF = 30
3 x WF = 30
3 x WF = 24
2 x WF = 10
8 x WF = 40
224
Option E
5 x WF = 50
5 x WF = 50
4 x WF = 40
5 x WF = 40
5 x WF = 25
3xWF= 15
220
Option F
5 x WF = 50
5xWF = 50
4 x WF = 40
4 x WF = 32
5 x WF = 25
6 x WF = 30
227
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3.0 ENVIRONMENTAL ANALYSIS USING THE ANALYTIC HIERARCHY
PROCESS
3.1 Finalized List of Alternatives
This is the finalized list of treatment alternatives for both the environmental analysis (using the
Analytic Hierarchy Process (AHP)) and the cost analysis (see Chapter 4). A description of the AHP is
included in Appendix A.
1. Option A+no macroencapsulation+centralized treatment
2. Option A+no macroencapsulation+mobile treatment
3. Option A+macroencapsulation+centralized treatment
4. Option A+macroencapsulation+mobile treatment
5. Option B+no macroencapsulation+centralized treatment
6. Option B+no macroencapsulation+mobile
7. Option B+macroencapsulation+centralized treatment
8. Option B+macroencapsulation+mobile treatment
9. Option C+no macroencapsulation+centralized treatment
10. Option C+no macroencapsulation+mobile treatment
11. Option C+macroencapsulation+centralized treatment
12. Option C+macroencapsulation+mobile treatment
3.2 Assumptions and Ground Rules
The first stages of the analytic hierarchy process were carried out in a brainstorming meeting in
June 2004 involving both EPA and SAIC personnel. To assist in the process, all participants discussed
and agreed to some ground rules, as follows:
• The intent of the AHP is to address environmental effects, not costs. An economic analysis of the
twelve alternatives was performed after completion of the AHP and is described in Chapter 4.
• Since there are twelve alternatives, the effort required to pairwise compare these against each
AHP criterion12 would be excessive - 12x11/2= 66 pairwise comparisons per criterion.
Therefore, the team instead defined a range of "intensities" for each criterion13.
• The environmental ranking arising from the AHP exercise is not sensitive to the total mass of
mercury (5,000, 12,000, or 25,000 tons). Therefore, there is no need to specify a mass for the
AHP14.
• "No macroencapsulation" means that the stabilized waste will be placed in the monofill exactly as
it is generated by the stabilization process. If the process ends with the waste solidifying in some
form of container, this container will be given no credit for reducing the rate of leaching.
• "Macroencapsulation in the best available medium" means macroencapsulation in a separate step
after stabilization. It was agreed that, for the purposes of both the AHP and the cost analyses, the
macroencapsulation technology will be the ARROW-PAK system, in which waste is sealed in
polyethylene containers prior to disposition in a monofill. The already-formed polyethylene
containers will be purchased from the manufacturers and filled and sealed at the stabilization site.
12 See Appendix A for an explanation of AHP criteria.
13 See also Appendix A for an explanation of AHP intensities.
14 There was some discussion about whether the mass of mercury might affect some of the criteria (e.g., higher
transportation risks for higher quantities), but this would not influence the rankings because all options would be
affected the same way.
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The ARROW-PAK system is expected to be available in a variety of sizes; the cost and
environmental analyses will incorporate appropriate assumptions for container size15.
• While many elements of the design and construction of the monofill will be independent of the
disposal alternatives, there might be some features that are technology dependent, such as the
composition of the liner and adjustments to the fill material to maintain pH. As discussed in
Appendix B, lime can be added to maintain (or promote) basic conditions and sulfur can be added
to maintain (or promote) acidic conditions, although many other soil and environmental
conditions will influence the ability of the monofill to maintain these pH conditions.
3.3 AHP Brainstorming Session
The EPA/SAIC brainstorming team defined a goal, developed criteria and subcriteria, and assigned a
range of intensities to each subcriterion.
3.3.1 The Goal
The goal is simply stated: "Minimize environmental impact during life cycle." Having this goal
helps the project team keep focused.
3.3.2 Development of Criteria and Subcriteria
The team brainstormed a list of criteria and subcriteria that they considered to be potential
discriminators among the twelve options in terms of environmental performance. Those criteria and
subcriteria are listed in Table 3-1.
3.3.3 Pairwise Comparison to Rank the Criteria and Subcriteria
The team pairwise compared each of the criteria, and then each of the subcriteria, in order to develop
weights that are intended to be a measure of the relative importance of each criterion and subcriterion.
The Expert Choice matrices for criteria and subcriteria are shown in Table 3-2. The resulting weights, as
calculated by Expert Choice software, are summarized in Table 3-1.
3.3.4 Development of "Intensities" for each Criterion and Subcriterion
As noted above, there are 12 alternatives. In principle, each of these should be pairwise-compared
against each of the criteria or subcriteria, leading to the need to perform 10 criteria x (12x11/2) = 660
pairwise comparisons. This is a rather large number (e.g., one comparison per minute would take
11 brainstorming hours), so the team decided to use an optional AHP technique whereby the criteria are
first assigned "intensities." These intensities are summarized in Table 3-1. As can be seen, these are
quite simple, most of them simply being "low," "medium," or "high." "Low" should be taken as meaning
"low potential impact on the environment," etc., so that "low" is always the most desirable outcome.
For the two subcriteria that are not allocated low, medium, or high intensities, one (the possibility of
mercury spills during transportation) is simply allocated two intensities - either a mercury spill is not
possible ("no," the most desirable situation), or a mercury spill is possible ("yes").16 The other (the
15 The fact that the ARROW-PAK technology was used in the present work does not mean that EPA endorses it as the best
available macroencapsulation process.
16 The simplicity of the intensities for the possible spillage of mercury during transportation is made possible because of a
simplifying assumption that was made in SAIC's original proposal. Either elemental mercury is treated at a centralized
stabilization facility and disposed of in a collocated monofill, in which case elemental mercury is transported to the treatment
location and could hypothetically be spilled en route: or mobile treatment facilities are sent to the current storage locations and
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possibility of spills of stabilized waste during transportation) is assigned three intensities ("none,"
transportation of "encapsulated" waste, and transportation of "non-encapsulated" waste.
In order to convert each assignment of intensities into a score or weight that can be used in Expert
Choice's ultimate calculation of the relative ranking of technologies, the team pairwise-compared the
intensities, as is summarized in the last column of Table 3-1.
The next step is to assign each alternative an intensity with respect to each criterion or subcriterion.
Thus, each alternative needs ten intensity assignments and there are 120 such assignments in total. The
team decided that they did not have enough knowledge at their fingertips to make these assignments.
Instead, the team identified factors and phenomena that need to be evaluated before deciding on the
intensity assignments. These factors are listed in Appendix B. After the brainstorming meeting, SAIC
gathered relevant information and made intensity assignments that were subsequently reviewed by the
EPA team. The basis for assigning the intensities is also discussed in Appendix B. This allowed Expert
Choice to be run so as to provide a baseline ranking of the twelve alternatives.
3.3.5 Assignment of Intensities to Alternatives
The results from Appendix B are summarized in Table 3-3. Appendix B describes in detail the
available data and the assignment of these intensities. As shown in Table 3-1, the assignment of
intensities for monofill disposal has a significant affect on results; information below is included to
further describe the data and limitations of information relevant to this particular criterion. As detailed in
Appendix B, factors included consideration of volatilization, presence of favorable pH conditions, long-
term stability of the waste, and long-term stability of the encapsulating material (if present).
Available data suggest that each of the technologies appear to perform best in different
environmental conditions (e.g., acidic or basic conditions). The alternatives were evaluated based on the
conditions expected to result in the lowest leachate concentrations, although as discussed previously land
disposal of treated elemental mercury is currently prohibited and therefore comparison of results to other
regulatory levels (e.g., UTS levels) is of interest but not as important as identifying the optimal range of
disposal conditions for each technology.
One benefit of macroencapsulation is to act as a barrier against disposal conditions which may
increase mobility of mercury from the treated waste. For example, all of the wastes leach mercury at
different pH. If landfill conditions deviate from the 'optimal' conditions suggested by available data, then
a waste without macroencapsulation would be expected to leach higher amounts of mercury than a
macroencapsulated one.
There is considerable uncertainty with regard to leaching performance over the long term. For
example, as discussed in Appendix B, mercuric sulfide (HgS) production is favored under alkaline
anaerobic conditions. One potential application of the result is that such conditions would favor the
transformation of residual elemental mercury to this stable form. An alternative application is that in an
anaerobic monofill in damp or wet conditions, ionic mercury (Hg+) and/or ionic mercury bisulfide
(HgS2=) may form and result in increased leaching over time.
In addition, incomplete data are available for many factors which affect leaching, such as pH
buffering capacity, or performance under conditions as a function of oxidizing/ reduction conditions (i.e.,
aerobic/ anaerobic).
3.4 Results of the Baseline Expert Choice Analysis
The 12 alternatives identified in Section 3.1 above were evaluated using the Expert Choice software.
The data from Tables 3-1 and 3-3 were used as inputs to the model. While the input to the model is
elemental mercury is stabilized there, so that elemental mercury will not be transported and there is no chance of a spill. It is
recognized that the real world situation may involve some transportation of both elemental mercury and of treated waste.
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somewhat narrative (e.g., intensities such as 'low,' 'medium,' and 'high'), the output provides a single
numerical result for each alternative.
To interpret the results, it is important to note that no alternative will achieve a 'perfect score,'
however defined. This is because the alternatives are evaluated partially against each other, so that the
total score will always equal unity no matter how many alternatives are evaluated. In addition, as the
number of alternatives increases or decreases, the score of each alternative will change to maintain the
same sum of scores of all alternatives (i.e., unity). In this manner, the results are best interpreted as scores
relative to each other, rather than the absolute value of an alternative's score.
Table 3-4 presents the Expert Choice results for each of the twelve alternatives discussed in the
previous section of this report. The table shows the score, and corresponding ranking, of each alternative
when considering all criteria. The results from the model were multiplied by 1,000 for convenience to
provide a score as a whole number, rather than as a decimal.
The following are some observations from Table 3-4:
• In general, mobile treatment alternatives score better than centralized treatment alternatives.
• There is a slight preference for macroencapsulation alternatives over alternatives which do
not include this additional treatment.
• All of the alternatives that include Option B technology score higher than alternatives that
include Option C technology. Alternatives that include Option A technology are more
scattered; one Option A alternative scores highest while a different Option A alternative
scores lowest.
Several additional analyses were conducted to explain or confirm these results. First, the team
evaluated whether results were reasonable based on the preferences and intensities assigned above.
Second, the team conducted additional sensitivity and uncertainty analyses with the Expert Choice
software to identify how changes in the preferences and intensities affect the rankings in Table 3-4. The
results of the sensitivity and uncertainty analyses are presented in Section 3-7. The reasonableness of the
above three conclusions derived from analysis of the AHP model output - is evaluated below (Sections
3.6.1-3.6.3.)
Another important consideration is the difference between the results for each alternative. It must be
determined if the magnitudes of these differences are large enough to be significant, or whether the results
indicate that the numerical results are similar. In general, small differences between one alternative and
another indicate that no discernible difference exists between the two. A determination of what is 'small'
is addressed primarily through the sensitivity and uncertainty analyses, as identified in Section 3.7. In
general, differences of 5 to 10 points out of 1000 can easily result from small changes in the intensities or
weightings, and therefore such differences between various alternatives are not expected to be significant.
3.4.1 Factors Which Influence the Scoring of Mobile Treatment Versus Centralized Treatment
Alternatives
Table 3-3 shows that transportation factors differ significantly between mobile and centralized treatment
alternatives. In other words, the greatest differences in intensities between mobile and centralized
treatment alternatives result from two of the three transportation factors (transport of mercury and
transport of waste). As shown in Table 3-1, transportation factors (particularly the transport of mercury)
significantly affect the scoring.
As explained previously, for all alternatives involving mobile treatment there is no transport of
elemental mercury, but there is transport of treated waste. The importance of these differences in
intensities is shown in Table 3-1, which shows that concerns about the transport of elemental mercury
(0.747) are much higher than concerns about the transport of treated waste (0.119). In addition, Table 3-1
shows that the potential environmental impacts during the transportation phase of the mercury lifecycle
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were determined to be the second-most important criterion (i.e., the weight of 0.216 is the second-highest
weight).
In summary, Tables 3-1 and 3-3 shows that it is reasonable to expect mobile treatment alternatives to
score higher than do centralized treatment alternatives, all other things being equal. This is because, by
assumption, there is no transport of elemental mercury associated with the mobile treatment alternatives
whereas, in the centralized treatment alternatives, all of the elemental mercury is transported to a
centralized treatment facility. The Team determined that potential impacts of elemental mercury spills
during transportation represent a significant potential risk, which should be minimized.
As discussed in Section 3.3.4, there is some simplification of the mobile and centralized treatment
alternatives. Mobile treatment is assumed to occur at a location with a fairly sizable quantity of mercury,
such as a DLA stockpile site, a chlor-alkali facility, or a mercury waste recovery facility. In the first two
examples, there will be no transport of elemental mercury (i.e., the mercury is already at the site). In the
third example, relatively small quantities of elemental mercury or mercury-containing wastes (e.g.,
thermometers) are sent by individual generators to a mercury recovery facility, and the recovered
elemental mercury is assumed to be treated without further transport. Therefore, the mobile treatment
alternatives as evaluated by the project team do not completely account for all movements of mercury,
although the transportation of these smaller shipments likely will be required regardless of whether
treatment occurs in a centralized location or a mobile location.
3.4.2 Factors Which Influence the Scoring of Macroencapsulation Versus Non-
Macroencapsulation Alternatives
Table 3-3 can again be used to identify the factors that significantly affect the scoring for
macroencapsulation and non-macroencapsulation alternatives. These occur with the transportation of
treated waste (i.e., for mobile treatment alternatives), and for the short-term disposal of treated mercury in
the monofill for two of the three treatment technologies (i.e., Options A and B). For each of these criteria,
macroencapsulation results in reduced risk versus non-macroencapsulation. In particular, Table 3-1
shows that potential environmental impacts during the disposal phase of the mercury lifecycle were
determined to be the most important criterion (i.e., 0.493 is the highest weight), showing that differences
in intensities associated with this criterion are expected to be very important. As shown in Table 3-3,
differences in the macroencapsulation options result in different intensities for the short term (<40 years)
and/or long term (>40 years) disposal. Appendix B identifies how these intensities were assigned.
Because macroencapsulation is primarily intended to reduce risks in the disposal phase, it is
reasonable to expect that these alternatives score higher than do alternatives that do not incorporate
macroencapsulation.
3.4.3 Factors Which Influence the Scoring of the Three Technology Options
There was significant scattering between each of the four alternatives associated with the Option A
technology, while there was a certain amount of clustering associated with the other two technologies.
Table 3-3 assists in explaining the results for the Option B and Option C technologies. Table 3-3 shows
that all six alternatives (including all four Option C alternatives) with an intensity of 'Moderate' for long-
term (>40 year) monofill stability have the lowest scores. As suggested by these results, and verified in
the uncertainty analysis (Section 3.7), the assigned intensity of this criterion is a principal factor in the
overall score for these six technologies. All four Option B alternatives have an intensity of 'Low' for this
criterion.
With respect to Option A, the results suggest that the technology has advantages and drawbacks,
which somewhat complicates the trends. It also suggests that other major differences between the
alternatives (i.e., centralized versus mobile treatment, and macroencapsulation versus non-
macroencapsulation) significantly affect the score for the Option A alternatives.
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3.5 Sensitivity and Uncertainty Analyses
Both sensitivity analyses and uncertainty analyses were conducted using the Expert Choice software.
These analyses served two functions: (1) to provide insight into how the overall scores were generated,
and (2) to identify how changes in the emphasis or intensities of different criteria would influence the
results. For this analysis, sensitivity refers to changes in emphasis of the different criteria (e.g., the five
first-level criteria identified in Table 3-1). Uncertainty refers to changes in the assignments of the
intensities (e.g., the values identified in Table 3-3). No analyses were conducted which changed the
overall structure of the model (e.g., adding new criteria).
3.5.1 Sensitivity Analyses
A sensitivity analysis is a type of 'what-if?' analysis. The intent is to identify how the results would
change if a particular criterion was deemed to be more (or less) important than that considered in the
baseline analysis results of Table 3-4. In particular, the sensitivity analysis changed the weights of each
of the five first-level criteria identified in Table 3-1. These changes were considered as follows:
• Changing the weight of the final disposal criterion from 49.3% to 75% (i.e., more important)
• Changing the weight of the final disposal criterion from 49.3% to 25% (i.e., less important)
• Changing the weight of the transportation criterion from 21.6% to 40% (i.e., more important)
• Changing the weight of the transportation criterion from 21.6% to 10% (i.e., less important)
• Changing the weight of the abnormal/ accidental operations criterion from 18.8% to 40%
(i.e., more important)
• Changing the weight of the abnormal/ accidental operations criterion from 18.8% to 10%
(i.e., less important)
• Changing the weight of the routine operations criterion from 6.5% to 13% (i.e., more
important)
• Changing the weight of the routine operations criterion from 6.5% to 3.2% (i.e., less
important)
• Changing the weight of the decommissioning criterion from 3.8% to 7.6% (i.e., more
important)
• Changing the weight of the decommissioning criterion from 3.8% to 1.8% (i.e., less
important)
In making these changes, the importance of each of the other four criteria was reduced proportionally
so that the contributions from all six criteria add to 100 percent. The sensitivity analysis results of the
three most sensitive criteria, which are the first six bullets listed above, are summarized in Table 3-5. The
remaining sensitivities are presented in Appendix A and make very small differences to the scores.
The sensitivity analysis considered large, but not extreme, changes in the weights of the first-level
criteria. The first column of results in Table 3-5, labeled 'baseline,' corresponds to the results in
Table 3-4. In this column, the importance of each of the five criteria is equal to the percentages listed in
Table 3-1 (e.g., transportation is 21.6%). The next columns list the sensitivity results for each of the first
six of the ten scenarios identified above. For example, for the transportation (high importance)
sensitivity analysis, the contribution of this criterion to the importance of all non-cost criteria was moved
from 21.6% (i.e., the 'baseline' reflected in the first results column) to 40% (+/- 0.2%). The importance
of each of the other four first-level criteria was reduced proportionally so that the contributions from all
five criteria add to 100 percent.
Some specific observations include the following:
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• As shown in Table 3-5, the same two alternatives remained the highest for both the baseline
analysis and the six sensitivity analyses (i.e., Option A and Option B with mobile treatment and
macroencapsulation). At the other extreme, the same single alternative remained the lowest in all
cases (i.e., Option A with centralized treatment and no macroencapsulation). This helps show the
stability in the results. Even as the weightings are changed over a wide range, both the rankings
and the absolute scores change in predicable ways.
• The baseline score is in between the extremes of the range for each alternative, again validating
the general model performance. For example, for the first row in Table 3-5, when evaluating
potential risks from transportation, the alternative score moves from 115 (for low importance) to
120 (for high importance). A score of 117 (the baseline) is achieved when the weighting is
midway between these extremes.
• The rank of each alternative is unchanged from the baseline when evaluating the potential for
accidents from operations, routine operations, and decommissioning. This suggests that the
alternatives are not sensitive to these criteria using the assigned intensities.
3.5.2 Uncertainty Analyses
Uncertainty identifies the extent to which variation in the information and data influences appropriate
conclusions. An uncertainty analysis is conducted to assess confidence in the results. In this section of
the report, uncertainty is incorporated into the analysis by using (1) ranges of available information and
data, and (2) 'what-if analyses for cases in which the true range is unknown or not well defined. For
example, a different calculation, or assessment, is generated for values associated with the extreme of a
range.
This section of the analysis discusses some of the sources of uncertainty identified in Appendix B that
are expected to impact the results and demonstrate their effect for selected alternatives. These areas of
uncertainty include the following:
• Monofill Disposal Stability for Option C- long term: Conflicting data are available regarding
the degree of mercury vapor generation from the Option C process, which is an area of
uncertainty affecting stability. This issue is discussed in more detail in Section 3.8.
• Monofill Disposal Stability for Option A: As discussed above, a single alternative scored
lowest in all sensitivity analyses (i.e., centralized treatment of Option A with no
macroencapsulation). As an uncertainty analysis, intensity values of this alternative were
changed to demonstrate how its score may rise.
• Other Monofill Disposal Stability: An obvious area of uncertainty for all alternatives is the
degree to which the disposal conditions will remain stable for both a short and a long period
of time (less than 40 years and greater than 40 years, respectively). This range is
demonstrated for one of the alternatives. In addition, the scale-up performance of the
treatment technologies themselves is uncertain with regard to their ability to treat relatively
large quantities of mercury for an extended period of time.
• Accidental Releases of Mercury During Operations: Risks of accidental releases of mercury
during the mercury treatment step may be higher or lower than evaluated. This range is
demonstrated for two of the alternatives.
A series of different analyses were conducted using the Expert Choice software for several of the
selected alternatives to better identify the impact that uncertainty has on the results. These analyses and
results are described in Table 3-6. Each row of the table represents an instance where data are changed
for just one of the alternatives. As shown, a total of 11 different uncertainty analyses were conducted.
The 11 sets of uncertainty analysis results in Table 3-6 show how the overall ranking of each
alternative is affected as the intensities of individual criteria are changed. These uncertainty analyses
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show that results change most significantly in the case of changing the intensity of the long term (>40
year) disposal criterion between 'Moderate' and 'Low.' This is shown for Reference Nos. 1 through 7.
For example, the lowest-scored Option A alternative in Table 3-4 (Reference No. 3) significantly
improves its score, from 48 (12th best) to 84 (6th best). Changes in the intensity of the shorter term
(<40 year) value also improve the score, but not as much (Reference Nos. 2 and 4).
Uncertainty with regard to accidental releases (mercury spills) during operations have a relatively
small effect on results. For example, an Option B alternative (Reference Nos. 8 and 9) still ranks high
regardless of whether the intensity is given a value of low, moderate, or high.
The uncertainty analysis can be used to identify important parameters in which further research may
be required. That is, particular attention could be placed on uncertain data, which significantly affect the
results. As shown above, this suggests that uncertainty with regard to long-term storage and disposal
represents one such parameter.
Further uncertainty analyses can take into account potential simultaneous variations in all of the
values that are input to the Expert Choice calculation. This can in principle be done by using Monte-
Carlo-based techniques. This was not feasible in the course of the present work.
3.6 Release Rates of Mercury
This section presents the results of a preliminary estimate of the quantity of mercury which may be
released from monofill disposal. Mercury may be released as a result of leaching and volatilization
mechanisms. For this preliminary analysis, the leachate concentration is multiplied by estimates of the
infiltration rate and the landfill area (i.e., the leachate volume) to estimate a leaching release rate.
Similarly, the quantity of mercury lost to volatilization is estimated to be equal to the quantity of landfill
gas generated multiplied by the gas concentration. The resultant estimates are intended to provide a range
reflective of uncertainty, and are based on simplified approaches to the actual physical mechanisms.
As shown in Figure B-l, the quantity of mercury present in leachate is dependent on site-specific
environmental conditions such as pH; such conditions may vary over time. The results of Figure B-l
were used as a guide in estimating the range of mercury concentration. Specifically, a lower bound of
leachate concentration for each of the three technologies is generally at or slightly below the universal
treatment standard (UTS) of 0.025 mg/L. For this analysis, a lower bound of 0.01 mg/L and an upper
bound of 1 mg/L are used. This wide range of concentration is intended, in part, to represent a range of
uncertainty. In practice, the actual concentrations may even be outside this range.
The results of a study (Wong, 1997) of four Florida landfills capped with synthetic liners were used to
estimate infiltration; the hypothetical mercury waste monofills also have synthetic liners and using a
report such as Wong (1997) simplifies the analysis by avoiding the need for site-specific modeling. This
is intended to provide an order-of-magnitude result, because these parameters may also change over time
particularly due to (1) differences in waste properties and (2) the quantity of water entering the monofill,
which is typically not equal to the quantity of leachate leaving the monofill due to unsteady-state
conditions. Based on Wong (1997), it is assumed that 5% of the rainfall infiltrates through the liner. For
the above reasons, there is variability associated with this percentage.
The sizes of the monofills are based on data presented in Appendices E through G of this report.
The sizes of the monofills are dependent on the technology type and whether or not the waste is
encapsulated; rather than evaluating each case separately an upper and lower end of the range is provided
for each waste quantity.
The quantity of mercury released (volatilized) is a function of the gas generation rate and the mercury
concentration. No data are available for gas generation rates from hazardous waste landfills; rather, a
great deal of information is available for municipal solid waste landfills (MSWLs) (AP-42; EPA 1998).
These MSW rates were used as a bounding estimate, as release rates for the case of a mercury monofill
are expected to be much less because of the absence of mechanisms available which would generate
landfill gas. The concentration of mercury in the gases is based on the volatilization data in Appendix B
with the upper bound corresponding to untreated elemental mercury.
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Table 3-7 summarizes the results for both volatilization and leachate release mechanisms. Table 3-7
shows ranges of leachate generation in the range of <1 to 1,500 g/yr and ranges of volatilization in the
range of 1 to 1,000 g/yr. These compare to the following data:
• The Swedish EPA (2003) has set a goal of 0.5 to 10 grams per year mercury for the leaching of
mercury waste in a deep rock repository. This goal is based on the assumption that the mercury
will have localized effects to fish at a hypothetical small lake. The Swedish EPA goals represent
the leaching pathway. The values in Table 3-7 (up to 1,500 g/yr) are in line with these Swedish
EPA goals, considering that the high end of the ranges in Table 3-7 represent undesirable
scenarios.
• The quantity of mercury vapor estimated to be released from monofill disposal (up to 1 kg/yr) is
insignificant as compared to other sources such as coal combustion (about 43 tons per year).
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Table 3-1. Goal, Criteria, and Subcriteria from EPA/SAIC AHP Brainstorming Session, June 17 and 18, 2004
Goal: Minimize Environmental Impacts During Life Cycle
First-Level Criterion (weights
as calculated by Expert Choice
in parentheses)
Cl. --during routine operation
of the stabilization facility13
(0.065)
C2. --during abnormal or
accidental operation of the
stabilization facility
(0.188)
C3. --during transportation
(0.216)
Second-Level Criterion
(weights as calculated by
Expert Choice in parentheses)
Cl-1. -solid waste streams
(other than final product)
(0.750)
Cl-2. -atmospheric
discharges
(0.250)
C2-1. -elemental mercury
spills
(0.833)
C2-2. -spills other than
elemental mercury
(0.167)
C3 - 1 . -of mercury to
stabilization facility
(0.747)
C3-2. -of stabilized waste to
monofill
(0.119)
C3 -3 . --of reagents to
stabilization facility
(0.134)
Purpose of Criterion
To assess the amount of solid
waste (other than the final
product) requiring disposal
To assess the level of
atmospheric discharges from
the facility
To assess the potential for
environmentally harmful spills
of liquid elemental mercury
during accident conditions
To assess the potential for
environmentally harmful spills
of materials other than liquid
elemental mercury during
accident conditions
To assess the potential for
accidental spills of elemental
mercury during transportation
To assess the potential for
accidental releases of stabilized
waste during transportation to
monofill
To assess the potential for
accidental releases of reagents
during transportation
Intensities"
low (1.0)
moderate (0.65)
high (0.265)
low (1.0)
moderate (0.55)
high (0.303)
low (1.0)
moderate (0.55)
high (0.303)
low (1.0)
moderate (0.55)
high (0.303)
No (1.0)
Yes (0.1 11)
None (1.0)
Encapsulated (0.225)
Not encapsulated (0.127)
low (1.0)
moderate (0.405)
high (0.164)
Expert Choice Pairwise
Comparison Matrix for
Intensities0
Low
Mod.
High
Low
Mod.
High
Low
Mod.
High
Low
Mod.
High
Low
Lo^v
Lo^v
Lo^v
2
Mod.
Mod.
3
Mod.
2
Mod.
High
3
High
3
High
3
High
3
2 Yes
No
Yes
NX
N
*N
N¥
Low
Mod.
High
Low
E
y
Mod.
2
NE
7
High
5
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Table 3-1. Goal, Criteria, and Subcriteria from EPA/SAIC AHP Brainstorming Session, June 17 and 18, 2004 (continued)
First-Level Criterion
(weights as calculated by
Expert Choice in parentheses)
C4. -during
decommissioning of the
stabilization unit
(0.038)
C5. -during storage in the
monofill
(0.493)
Second-Level Criterion
(weights as calculated by
Expert Choice in parentheses)
None
C5-1. - expected ease of
maintaining environmental
conditions (up to 40 years)
(0.200)
C5-2. -expected long-term
susceptibility to degradation
(0.800)
Purpose of Criterion
To assess the potential for
potentially harmful
environmental effects during
decommissioning
To assess the potential for
excessive leaching during
storage
To assess long-term stability
Intensities"
low (1.0)
moderate (0.55)
high (0.303)
low (1.0)
moderate (0.225)
high (0.127)
low (1.0)
moderate (0.225)
high (0.127)
Expert Choice Pairwise
Comparison Matrix for
Intensities
Low
Mod.
High
Low
Mod.
High
Low
Mod.
High
Low
Low
Lo^v
5
Mod.
Mod.
2
Mod.
High
3
High
7
High
7
a In order of decreasing desirability. Values in parentheses are weightings calculated by the Expert Choice software after the pairwise comparison that is summarized ji the
adjacent column.
b Includes macroencapsulation where relevant.
c. Shaded areas represent areas of the matrix that are not used by the Expert Choice Software. The numbers in the matrices represent the relative importance of the intensities as
determined by pairwise analysis. For example, in the case where there is a 2 in the cell that has "low" to the left and "mod" above, the team judged that it is twice as desirable for a
technology to have a low intensity than a moderate intensity. For a more detailed explanation of the Expert Choice matrices, see Appendix A.
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Table 3-2. Expert Choice Matrices for Criteria and Subcriteria
Table 3-2a. - First Level Criteria
Cl.
C2.
C3.
C4.
C5.
Cl.a
C2.
fb
-3
C3.
-4
1
C4.
2
5
7
C5.
-7
-3
-3
-9
a. The numbering system is explained in Table 1
b. A positive number implies that the criterion in the left hand column is more important than the criterion in the top row.
A negative number implies that the criterion in the top row is more important than the criterion in the left hand column.
Table 3-2b. - Second level criteria
Associated with Criterion 1
Table 3-2c. - Second Level Criteria
Associated with Criterion 2
Cl-1.
Cl-2.
Cl-1.
Cl-2.
3
C2-1.
C2-2.
C2-1.
C2-2.
5
Table 3-2d. - Second level criteria
Associated with Criterion 3
Table 3-2e. - Second Level Criteria
Associated with Criterion 5
C3-1.
C3-2.
C3-3.
C3-1.
C3-2.
7
C3-3.
5
1
C5-1.
C5-2.
C5-1.
C5-2.
-4
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Table 3-3. Assignment of Intensities to Treatment and Disposal Alternatives1
Treatment and Disposal
Option
Option A+NMEa + CTAc
Option A+ NMEb + MTAd
Option A+ ME + CTA
Option A+ ME + MTA
Option B+ NME + CTA
Option B+ NME + MTA
Option B+ ME + CTA
Option B+ ME + MTA
Option C+ NME + CTA
Option C+ NME + MTA
Option C+ ME + CTA
Option C+ ME + MTA
Routine Operations
Solid
Waste
Discharges
Moderate6
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Low
Moderate
Low
Moderate
Atmospheric
Discharges
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Accidental
Releases
Mercury
Spills
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Other
Spills
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Transportation
Mercury
to
Treatment
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Waste
to
Monofill
No
NME
No
ME
No
NME
No
ME
No
NME
No
ME
Reagents
Low
Low
Low
Low
Low
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
Decom-
missioning
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Monofill Storage
<40
years
Moderate
Moderate
Low
Low
Moderate
Moderate
Low
Low
Low
Low
Low
Low
>40
years
Moderate
Moderate
Low
Low
Low
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
1. The assignment of these intensities is discussed in Appendix B. The uncertainty analysis (Section 3.7.2) helps to quantify the impacts of these selections.
a. NME = Not Macroencapsulated. b. ME = Macroencapsulated.
c. CTA = Centralized Treatment Alternative, d. MTA = Mobile Treatment Alternative.
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Mercury Environmental and Economic Study
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Table 3-4. Environmental Analysis - Summary of Baseline Results for 12 Evaluated Alternatives
Treatment Scenario
Treatment Process
Option A
Option B
Option B
Option A
Option B
Option B
Option C
Option C
Option A
Option C
Option C
Option A
Macro-
Encapsulation
With
With
Without
With
With
Without
Without
With
Without
Without
With
Without
Fixed or Mobile
Facility
Mobile
Mobile
Mobile
Fixed
Fixed
Fixed
Mobile
Mobile
Mobile
Fixed
Fixed
Fixed
Number of alternatives evaluated
Total
Average score (total divided by 12, the number of alternatives)
Overall Ranking
Score
(as fraction of 1,000)
117
117
108
98
98
89
73
73
66
57
57
48
12
1,000
83
Rank
(Best to Worst)
1
1
3
4
4
6
7
7
9
10
10
12
—
—
—
Shading indicates the highest-ranking alternatives.
Distributive mode; overall inconsistency factor from Expert Choice: 0.02 (good).
Average value is provided for reference and identifies the average score for the twelve evaluated technologies.
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Mercury Environmental and Economic Study
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Table 3-5. Environmental Sensitivity Analysis
Treatment Scenario
Treatment
Process
Option A
Option B
Option B
Option A
Option B
Option B
Option C
Option C
Option A
Option C
Option C
Option A
Macro-
Encapsul
ation
With
With
Without
With
With
Without
Without
With
Without
Without
With
Without
Fixed or
Mobile
Facility
Mobile
Mobile
Mobile
Fixed
Fixed
Fixed
Mobile
Mobile
Mobile
Fixed
Fixed
Fixed
Average
Total
Ranking3
Baseline (from
Table 3-4)
Score
117
117
108
98
98
89
73
73
66
57
57
48
83
1,000
Rank
1
1
3
4
4
6
7
7
9
10
10
12
—
—
Importance on Disposal
Sensitivity:
High
Score
124
124
111
115
115
102
60
60
48
52
52
39
83
1,000
Rank
1
1
5
3
3
6
7
7
11
9
9
12
—
—
Sensitivity:
Low
Score
110
110
105
82
82
78
85
86
84
61
61
56
83
1,000
Rank
1
1
3
7
7
9
5
4
6
10
10
12
—
—
Importance on Transport
Sensitivity:
High
Score
120
120
113
85
85
79
84
85
81
52
52
47
83
1,000
Rank
1
1
3
4
4
9
7
4
8
10
10
12
—
—
Sensitivity:
Low
Score
115
115
105
106
106
96
66
66
57
60
60
48
83
1,000
Rank
1
1
5
3
3
6
7
7
11
9
9
12
—
—
Importance on Accidents
Sensitivity:
High
Score
108
108
101
94
94
88
76
76
71
64
64
57
83
1,000
Rank
1
1
3
4
4
6
7
7
9
10
10
12
—
—
Sensitivity:
Low
Score
120
120
110
100
100
90
72
72
64
54
54
44
83
1,000
Rank
1
1
3
4
4
6
7
7
9
10
10
12
—
—
Shading indicates the highest-ranking alternatives. In the sensitivity analysis for each criterion, the importance of the criterion is set at higher or lower than its baseline value, as
identified in the text. The four other criteria comprise the remainder, proportional to their original contributions.
a. Scores normalized to total 1,000.
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Mercury Environmental and Economic Study
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Table 3-6. Uncertainty Analysis for Mercury Management Alternatives
Ref.
No.
0
1
2
o
J
4
5
6
7
8
9
10
11
Alternative
All
Treatment
Process
Option C
Option C
Option C
Option C
Option A
Option B
Option B
Option C
Macro-
Encapsulat
ion
Without
With
Without
With
Without
With
Without
With
Fixed or
Mobile
Facility
Mobile
Mobile
Fixed
Fixed
Fixed
Mobile
Mobile
Fixed
Criteria
Change in Intensity for Uncertainty
Analysis
Baseline
Change
Baseline for comparison: Same results as Table 3-4
Monofill Disposal,
>40 years
Monofill Disposal,
<40 years
Monofill Disposal,
>40 years
Monofill Disposal,
both <40 years and
>40 years
Monofill Disposal,
<40 years
Monofill Disposal,
>40 years
Monofill Disposal,
both <40 years and
>40 years
Accidental Releases
(Mercury Spills)
Moderate
Moderate
Moderate
Moderate
Low
Low
Low
Moderate
Moderate
Low
Low
Low
Low
Moderate
Moderate
Moderate
Low
High
Low
High
Initial Result
(Table 3-4)
Score
—
73
73
57
57
48
117
108
57
Rank
—
7
8
10
11
12
2
3
11
Uncertainty
Analysis Result
Score
—
99
99
82
82
55
84
92
108
76
68
117
102
66
51
Rank
—
3
3
6
6
12
6
4
2
6
9
1
3
9
11
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Table 3-7. Preliminary Release Rates for Mercury Monofill Disposal
Pathway
Leachate
Volatilization
Mercury
Quantity,
MT
5,000 MT
12,000 MT
25,000 MT
1,000 MT/yr
Hg
Concentration
0.01-1 mg/L
O.Ol-lOmg/mS
Design Basis
5% Infiltration Rate;
Precipitation of 5 -60 in/yr
(continental U.S. range)
Maximum gas generation
100 m3/MT (AP-42)
Monofill
size, acre
0.6-1
1.3-2.2
3-5
—
Release, g/yr
0.2 - 300
0.3-700
0.8-1,500
1 - 1,000
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Mercury Environmental and Economic Study Final Report April 2005
4.0 ECONOMIC ANALYSIS
The purpose of this chapter is to provide estimates of the cost of various methods for the long-term
disposition of elemental mercury. As previously described, twelve treatment alternatives are under
consideration:
1. Option A + no macroencapsulation + centralized treatment
2. Option A + no macroencapsulation + mobile treatment
3. Option A + macroencapsulation + centralized treatment
4. Option A + macroencapsulation + mobile treatment
5. Option B + no macroencapsulation + centralized treatment
6. Option B + no macroencapsulation + mobile treatment
7. Option B + macroencapsulation + centralized treatment
8. Option B + macroencapsulation + mobile treatment
9. Option C + no macroencapsulation + centralized treatment
10. Option C + no macroencapsulation + mobile treatment
11. Option C + macroencapsulation + centralized treatment
12. Option C + macroencapsulation + mobile treatment
Three different masses of mercury were considered for each of the treatment alternatives:
a. 5,000 metric tons,
b. 12,000 metric tons, and
c. 25,000 metric tons.
Thus, 36 treatment and disposal alternatives were considered. In addition, cost estimates have been
prepared for long-term storage of the three masses of elemental mercury in aboveground facilities without
any treatment or disposal efforts, making a total of 39 cost estimates in all. This chapter presents the
approach, the cost estimate results, and the assumptions used in producing the cost estimates.
Each of the thirty-six cost estimates for treatment and disposal includes the following elements:
• Capital costs for the treatment facility,
• Capital costs for the macroencapsulation facility (if part of the alternative)
• Operating and maintenance costs for the treatment process,
• Operating and maintenance costs for the macroencapsulation process (if part of the
alternative),
• Costs associated with the mobile treatment alternative,
• Transportation costs associated with each alternative,
• Costs of storing elemental mercury prior to treatment
• Decommissioning costs for the treatment facilities,
• Monofill engineering and construction costs,
• Monofill operating costs, and
• Costs of maintaining and monitoring the monofill for a thirty-year period following its
closure.
Each of the three storage alternatives contain the costs of maintaining the existing stockpile (assumed
to be 5,000 MT) in storage, adding to storage space as necessary, and transporting elemental mercury to
the storage facility(ies).
In this chapter, Sections 4.1, 4.2, 4.3, and 4.4 describe the assumptions and bases for the cost
estimates of the treatment and encapsulation processes, the monofill, storage, and transportation
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respectively. Section 4.5 discusses uncertainties, and Section 4.6 presents results and interpretation.
Various appendices contain detail on input to the cost estimates: Appendix C - Option A Treatment
Process; Appendix D - Option B Treatment Process; Appendix E Monofill Estimate for Option A
Treatment Process; Appendix F - Monofill Estimate for Option B Treatment Process; and Appendix G -
Monofill Estimate for Option C Treatment Process. Note that there is no Appendix for the Option C
Treatment Process. This is because the Option C vendors provided a great deal of proprietary material.
However, the Option C costs were calculated on the same basis as were the costs for the other options.
4.1 Assumptions and Bases for Cost Estimates
This section describes the assumptions and bases for the cost estimates: 4.1.1 General Assumptions;
4.1.2 Mercury Treatment Processes; 4.1.3 Macroencapsulation; 4.1.4 Mobile Treatment alternative;
4.1.5 Monofill; 4.1.6 Storage; and 4.1.7 Transportation.
4.1.1 Background and General Assumptions
• Possibly the most important general assumption is that mercury will be treated at a rate of 1,000
Metric Tons (MT) per year. This is a reasonable assumption in light of the rate at which surplus
elemental mercury is becoming available, as is described below.
• For treatment and disposal alternatives, it is assumed that the treatment facility will continue in
operation until all of the mercury has been treated and placed in a monofill. This will take 5 years
for 5,000 MT, 12 years for 12,000 MT and 25 years for 25,000 MT. Once all of the mercury has
been treated, the monofill will be finally closed and monitored for 30 further years.
• For continuing storage alternatives, it is assumed that costs will be calculated for the same length
of time as for the corresponding treatment alternative: 5 +30 years for 5,000 MT; 12 + 30 years
for 12, 000 MT; and 25 + 30 years for 25,000 MT.
• Costs for each scenario are presented as a Net Present Value (NPV) of a future stream of 2004
constant dollar costs using a 30-year real discount rate of 3.5% per year provided by the Office of
Management and Budget (OMB 2004a, 2004b).
According to the Mercury Management Environmental Impact Statement (MMEIS; DLA 2004), the
principal amounts of elemental mercury currently in storage at Federal sites in the US are kept in 76 Ib
(34 kg) flasks at four sites: (a) the New Haven Depot near New Haven, IN; (b) the Somerville Depot in
Hillsborough, NJ; (c) the Warren Depot near Warren, OH; and (d) in a building at the U.S. Department of
Energy's Y-12 National Security Complex in Oak Ridge, TN.
At New Haven, Somerville, and Warren, the flasks are stored in 30-gal (114-1) steel drums for extra
protection, called "overpacking." Each drum contains 6 flasks. The overpack drums meet the U.S.
Department of Transportation's (DOT's) packaging requirements for shipping hazardous materials by
highway or rail (Title 49 Code of Federal Regulations [CFR] 173.164(d)(2)). The drums are banded
together in groups of 5 and stored on metal catch trays. The catch trays are on 4-ft (1.2m) square wooden
pallets. Each drum contains 456 Ib (207 kg) of elemental mercury, and each pallet carries 2,280 Ib (2.28
tons or ~ 1 metric ton (MT)).
Many of the flasks at New Haven, Somerville, and Warren are of the older, welded variety made in
the 1940s and 1950s. At Y-12, however, the mercury was transferred to newer, seamless flasks in the
mid-1970s. These flasks are much less susceptible to leakage and have not been overpacked. They are
stored in groups of 45 on wooden pallets that measure 38 in by 38 in by 20 in (96 cm by 96 cm by 51
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Mercury Environmental and Economic Study
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cm). Thus, each pallet carries 3,420 Ib (1,554 kg
mercury at each site is summarized in Table 4-1.
1.5 MT) of elemental mercury . The amount of
Table 4-1. Current U.S. Government Mercury Stockpiles"
Location
New Haven Depot
Somerville Depot
Warren Depot
Y-12, Oak Ridge
Total
Owner
DNSC
DNSC
DNSC
DNSC
DOE
DNSC
DOE
All
Quantity in
Storage
tons/(MT)
614 (557)
2,885 (2,617)
621 (563)
770 (699)
1,130(1,026)
4,890 (4,436)
1,130(1,026)
6,020 (5,462)
Number of Flasks
16,151
75,880
16,355
20,276b
29,724b
128,662
29,724
158,386
Number of
Drums
2,692
12,647
2,726
3,379C
4,954 c
21,444
4,954 c
26,398
a. Source: DLA (2004).
b. These stockpiles are collocated in Y-12.
c. Number of drums required to overpack the flasks (currently not overpacked).
Alternative 1 - 5,000 MT
For the case of continued storage, Alternative 1 is quite close to the status quo at DNSC and DOE
locations. Therefore, Alternative 1 is costed as if storage will continue there and can be scaled directly
from Appendix D of the MMEIS. For example, the current DNSC stockpile of 4,436 metric tons requires
approximately 200,000 ft2 (18,581 m2) of forklift-accessible flat space inside a structure. 5,000 MT
would therefore require ~ 225,000 ft2 (~ 21,000 m2), an increase of a factor of 1.127, and items such as
rent can be scaled accordingly.
The need for storage will not vanish immediately even if the waste is treated. For the centralized
treatment alternative, it is assumed that elemental mercury will be transported from the current storage
locations to the treatment facility at a rate of 1,OOOMT per year for five years. Each 1,000 MT occupies
45,000 ft2 (~ 4,200 m2). The MMEIS gives information that can be translated into a cost per MT per year
for storing elemental mercury. As the stockpile is depleted, the analysis simplifies by assuming that the
storage costs throughout the year are those for the amount of mercury in storage at the mid-point of the
year, and that storage costs will decrease accordingly until all the mercury has been treated. The same
rate of depletion of the existing stockpile is assumed for both the centralized and mobile treatment
alternatives.
Alternative 2 - 12,000 MT
For this alternative, it is assumed, as for alternative 1, that there is 5,000 MT of elemental mercury
in existing storage. The remaining 7,000 MT becomes available at a uniform rate over a period of
12 years, i.e., at a rate of 583 MT/yr18. For the case of continued storage, therefore, the amount in the
stockpile will increase by this amount each year, and additional storage space needs to be made available.
As explained above, the amount of mercury in storage at the mid-point of each year is multiplied by the
unit yearly cost per MT to provide an estimate of total storage costs per year.
When the waste is treated at a centralized facility, it is assumed that the 583 MT/yr of "new"
elemental mercury is transported directly to the treatment facility, thus obviating the need for intermediate
17 In the cases where this mercury is transported to a central treatment facility, it is assumed that they will first be placed 6 at a
time in 30-gal steel drums in order to satisfy DOT requirements.
18 Note that the assumption that there is about 5,000 MT in existing storage and that additional elemental mercury becomes
available at a rate of a few hundred MT per year is consistent with data in Appendix D of the MMEIS.
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Mercury Environmental and Economic Study Final Report April 2005
storage. The remaining 417 MT/yr required to make up the assumed treatment rate of 1,000 MT/yr is
drawn down from storage. Every year, therefore, there is need for 18,800 ft2 (1,747 m2) less storage
space. The same rate of depletion of the existing stockpile is assumed for both the centralized and mobile
treatment alternatives.
Alternative 3 - 25,000 MT
For this alternative, it is assumed, as for Alternative 1, that there is 5,000 MT of elemental mercury
in existing storage. The remaining 20,000 MT becomes available at a uniform rate over a period of 25
years, i.e., at a rate of 800 MT/yr. For the case of continued storage, therefore, the amount in the
stockpile will increase by this amount each year, and additional storage space needs to be made available.
When the waste is treated at a centralized facility, it is assumed that the 800 MT/yr is transported
directly to the treatment facility, thus obviating the need for intermediate storage. The remaining 200
MT/yr required to make up the assumed treatment rate of 1,000 MT/yr is drawn down from storage. The
same rate of depletion of the existing stockpile is assumed for both the centralized and mobile treatment
alternatives.
Observation
Note that the authors of Appendix D of the MMEIS calculated that approximately 388 MT of
elemental mercury was added to inventory in 1997. As noted above, the 12,000 MT and 25,000 MT
alternatives assume that elemental mercury becomes available at the rate of 583 MT/yr and 800 MT per
year, respectively. These rates are within a factor of about two of the 1997 experience. The current work
did not include an analysis of whether there is enough mercury in consumer inventories in the US and a
sufficient rate of decommissioning to ensure that total amounts of 12,OOOMT or 25,000 MT will in fact be
made available for long-term disposal. However, the assumed rate of disposal of 1,000 MT per year is
not unreasonable.
4.1.2 Mercury Treatment Processes
This section provides assumptions and bases for the costs of each of the three treatment technologies.
4.1.2.1 Option A
Option A is a process developed to treat elemental mercury and mercury contaminated waste and
debris. Option A is a two stage, single vessel batch process that results in mercuric sulfide stabilized in a
sulfur polymer matrix. In the process' first step, mercury is reacted with powdered sulfur polymer cement
and additives to form a stable mercury sulfide compound. Next, the chemically stabilized mixture is
melted, mixed, and cooled to form a monolithic solid waste form in which the stabilized mercury particles
are microencapsulated within a sulfur polymer matrix.
A process diagram is shown in Figure 4-1. The process's two main steps, (1) reaction of mercury
with sulfur and (2) melting/mixing in a sulfur polymer matrix, occur in a vertical mixer/dryer. The
process requires some heating, so the mixer is jacketed for heat transfer. The process produces some
mercury vapor, so a ventilation system is required to filter out the vapor. Since the process is heated, heat
exchangers are included in the ventilation system.
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Mercury Environmental and Economic Study
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Figure 4-1. Option A Process
Sodium sulfide
Mercury
Sulfur
Polymer
Cement
(SPC)
Filtered
exhaust
gases
Off-gas piping
Fluid heat
transfer system
(water jacket)
Output Valve
Condensed
Hg
Recycle Hg
back to
process
55-gallon drum
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Appendix C includes further diagrams for the Option A process that show the equipment and
materials used for the cost estimates. Each of the diagrams shows the sizing for process capacity, reagent
consumption, and the major equipment. The assumptions shown on the process diagram are described
below.
The following is the key information for sizing the Option A process: one 35 ft3 mixer can process
525 kg per shift. This mixer size was based on published information in which the vendor states that a 35
ft3 mixer is under development. This represents a scaling up by a factor of 35 from the pilot mixer of 1
ft3. Five mixers in parallel operating two shifts per day can process the assumed mass of mercury per
year (1,000 metric tons). The major equipment necessary to operate these mixers is shown on the process
diagram, which lists the major equipment and its cost. These costs are summarized in Table 4-2. The
cost of the major equipment is used to estimate the overall capital costs for the Option A process.
Table 4-2. Major Equipment for the Option A Process
Component
Sulfur Polymer
Cement Feeders
Sulfur Polymer
Cement Hopper
Sodium Sulfide
Pump
Sodium Sulfide
Feed Valves
Sodium Sulfide
Tank
Mixer
Heater
Liquid Nitrogen
Tank
Off-gas Ducts
HEPA Filter
Carbon Filter
Vacuum Pump
Chiller
Condenser
Forklift
Price
$44,100
$10,650
$15,000
$330
$557
$180,000
$26,495
$627
$506.47 per 100 ft2
= $5,065
$306.50
$47.25
Pump
$4,800
Electric Motor
$1,187
Total: $5,987
$5,366
$4,186
$25,000
Reference
RES (2002) account
100-55, page 2
Perry and Green
(1997) Table 9-50
Bubb (2004a)
RES (2002) account
15-47, page 27
MSC (2004)
Bubb (2004b)
Bubb (2004b)
LACO (2004)
RES (2002) account
15-9, page 1
Grainger (2004) pg
3575
Grainger (2004) pg
3571
RES (2002) account
100-1 10, page 2
RES (2002) account
100-653, page 2
MSC (2004) page
4477
MSC (2004) page
4476
Solis (2004)
Comments
Conveyer
20-525 cf/hr
r4,2oof57
1, 1,000 )
= $10,650
Vertical Pump and electric motor. Designed
for concentrated acid.
Stainless Steel Gate Valves, 200#, Socket
Weld, 3/4 -inch Sch 40.
Polyethylene Double-Walled Tank
100 gal
Vertical Vacuum Blender
35 cubic feet
Jacketed
Motor, Valves, Controls, Thermocouples
72 kW
2L N2 reservoir (16 hour holding time)
24 GA ductwork (20" diameter), 1000 ft2
Air Handler HEPA Air Filter
1,100 CFM, 24"x24"xll.5", 99.97%
efficient
Activated Carbon Disposable Filters
250 FPM, 24"x24"x2"
Assumed similar cost to a fan:
Vaneaxial Fan
44-inch diameter 1 - 30 HP
15,000 -47,000 CFM
Electric Motor
7.5 HP AC Motor
LytronRC045
20,100 BTU/hr, 4.3 gpmPump
Liquid-to-air heat exchanger model 6640 x 2
+ $2,000 allotment for vessel and
manufacturing
4,000-6,000 Ib capacity Electric Drive
Notes: price gives the costs for one piece of equipment. Quantities of equipment required are given in Appendix C.
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The key information for the mass components in each treatment batch is as follows:
- 33% weight mercury,
- 65% weight sulfur polymer cement, and
- 2% weight sodium sulfide.
Thus, the mass of treated product is approximately 3 kg/kg mercury treated.
For 1,000 MT of mercury processed per year, this sets the amount of reagents required per year. This
also means that there are 3,000 MT of waste product for disposal each year. Table 4-3 lists the materials
used in the Option A process and their costs. This includes reagents and drums into which treated
mercury is placed.
Table 4-3. Material Costs for Option A Process
Component
Sulfur Polymer
Cement
Sodium Sulfide
55-gallon drums
Price
$0. 12 /lb delivered
($0.2647 kg)
$10.53 /kg delivered
$33 per barrel delivered
Reference
Chang (2001)
Lab Depot (2004)
Ten Siethoff
(2004c)
Comments
Martin Resources
(Odessa, TX)
Chement 2000
Na2S (36% water of
crystallization)
1.5 g/cm3
Staff salary costs and utility costs for the Option A treatment process are estimated on the process
diagram in Appendix C. These costs are included in the annual O&M costs for the treatment process.
Staff salary is based on the Website Salary.com (Salary.com 2004). For all three options, the calculated
O&M costs include the assumption that the facility is down 20% of the time for maintenance and repair.
4.1.2.2 Option B
The Option B process treats elemental mercury or mercury containing wastes. A process diagram is
shown in Figure 4-2. The process, performed in batches, consists of the following steps:
1. A sulfur-containing compound (otherwise known as the amalgamating agent), preferably
elemental sulfur in powdered form, is spread throughout a mixer.
2. The mercury-containing material is added to the mixer and mixed.
3. A polysulfide is added and mixed to activate the reaction between sulfur and mercury. Typically
this polysulfide is calcium polysulfide or sodium polysulfide.
4. The resulting granular waste is poured into drums.
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Mercury Environmental and Economic Study
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Figure 4-2. Option B Sulfide Process
mciouiy
OUlTUI
^
\
J
,
N
•^
*
•«•.
•**.
/
s7
H
\/
_ , ., . Ventilation System (draws Filtered
1 suction from the mixer) exndu&i
~L . ., , cr ^> _, gases
p Water sc^ ^^ ^ 1 a
^jacket - - ^^-......^ *<^ (^/
, , nbrA Niter uaroon riiter blower
9 Knockout drum
Treated Mercury
^^
— •
—•-
55-gallon drum
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Mercury Environmental and Economic Study Final Report April 2005
As with the Option A process, a ventilation system with filters is required. Appendix D includes
further diagrams for the mercury treatment processes that show the equipment and materials used for the
cost estimates. Each of the diagrams shows the sizing for process capacity, reagent consumption, and the
major equipment. The assumptions and sources of information shown on the process diagrams are
discussed below.
The following is the key information for sizing the Option B process:
- 375 kg of mercury per batch19,
- 3 batches per mixer-shift, and
- 80% utilization of the equipment.
Using this information, five mixers operating in parallel can process the required mass of mercury per
year (1,000 tons). The major equipment necessary to operate these mixers is shown on the process
diagram, and Table 4-4 lists the major equipment and its cost. The cost of the major equipment is used to
estimate the overall capital costs for the Option B process.
The following is the key information regarding the mass components in each treatment batch:
- 67% mercury,
3% polysulfide, and30% sulftir.Thus, the mass of treated product is approximately 1.5kg/kg mercury
treated.
For 1,000 tons of mercury processed per year, this sets the amount of reagents required per year. This
means that 1,500 MT of waste product needs to be disposed of each year from the Option B process.
Table 4-5 lists the materials used in the process and their costs. This includes reagents and drums into
which treated mercury is placed.
Staff salary costs and utility costs for the treatment process are estimated on the process diagram.
These costs are included in the annual O&M costs for the treatment process. Staff salary is based on
information from Salary.com.
4.1.2.3 Option C
The final product of Option C is a monolithic amalgamated material that is encapsulated in
polyethylene-lined steel drums. The process, which is performed in batches in drums, consists of steps to
create an amalgam and (if required) additional steps to create a stabilized form. A process diagram is
shown in Figure 4-3.
The process steps are as follows:
1. A proprietary powdered reagent is added to elemental mercury in a drum and mixed.
2. Another proprietary powdered reagent is added to the drum and mixed.
3. A proprietary liquid reagent is added to the drum and mixed.
4. The stabilized form is created by mixing in three more proprietary reagents (two powdered, one
liquid) and curing.
19 This batch size was confirmed in discussions with Vendor B and represents scaling up by a factor of five from the
existing mixer.
4-9
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Mercury Environmental and Economic Study
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Table 4-4. Major Equipment for the Option B Process
Component
Mixers
Polysulfide
Pumps
Polysulfide Feed
Valves
Sulfur Hoppers
Crane
Water Heater
Ventilation
System Ducts
HEPA Filter
Carbon Filter
Knockout Drum
Blower
Forklift
Price
$65,000
Pump
$2,400
Electric Motor
$1,187
Total= 3,587
$760
$26,400
$78,000
$2,769
$506.47 per 100 ft2 =
$5,065
$306.50
$47.25
$6,300
Fan
$4,800
Electric Motor
$1,187
Total: $5,987
$25,000
Reference
Bubb (2004d)
RES (2002) account
100-280, page 2
RES (2002) account
100-653, page 2
RES (2002) account
15-47, page 27
RES (2002) account
100-45, page 4
RES (2002) account
100-495, page 4
RES (2002) account
15-28, page 2
RES (2002) account
15-9, page 1
Grainger (2004)
Grainger (2004)
Perry and Green
(1997) page 9-69
Fan
RES (2002) account
100-1 10, page 2
RES (2002) account
100-653, page 2
Solis (2004)
Comments
60 cubic foot mixer
Pump
Vertical Split Case Centrifugal Pump
Max operating pressure 285 psi
50 gpm and 200 ft of head
7.5 HP
Electric Motor
7.5 HP AC Motor
Stainless Steel Gate Valves, Screwed
2-inch Sch 40
Gravimetric Feeder
720 - 24,000 Ib / hr
Overhead traveling bridge crane, Floor
operated
3 ton, 75 foot span
Commercial water heater, gas
50 gallons, 90,000 BTU/hr
24 GA ductwork (20" diameter), 1000 ft2
Air Handler HEPA Air Filter
1,100 CFM, 24"x24"xll.5", 99.97%
efficient
Activated Carbon Disposable Filters
250 FPM, 24"x24"x2"
Pressure Vessel Horizontal Drum 1,000 gal
Fan
Vaneaxial Fan
44-inch diameter 1 - 30 HP
15,000 -47,000 CFM
Electric Motor
7.5 HP AC Motor
4,000-6,000 Ib capacity
Electric Drive
Notes: price gives the costs for one piece of equipment. Quantities of equipment required are given in Appendix D.
4-10
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Mercury Environmental and Economic Study
Final Report April 2005
Figure 4-3. Option C Process
\
Filter
Activated
Carbon
zT)
Blower
Elemental
Mercury
vl'
Move drum to
next step
Reagent # 3
Storage Vessel
(liquid)
Proprietary mixing/
handling device
Move drum to
next step
30
gal
Move drum to
next step
Amalgam
Product
Reagent # 4
Storage Vessel
(liquid)
30
gal
Amalgam
Product
Move drum to
next step
Cure for 24
hours
Stabilized
Waste
Proprietary mixing/
handling device
30
gal
4-11
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Mercury Environmental and Economic Study
Final Report April 2005
As with the other processes, a ventilation system with filters is required.
No Appendix is shown for this process to protect proprietary details. The principal assumptions and
sources of information for costing the process are described below.
Two parallel amalgamation process lines and three parallel stabilization process lines can treat
1000 tons of mercury per year. The processes will operate two shifts per day. The major equipment
necessary to operate these process lines is shown on the process diagram in Attachment C, and Table 4-6
lists the major equipment and its cost. The cost of the major equipment is used to estimate the overall
capital costs for the Option C process.
Table 4-5. Material Costs for Option B Process
Component
Polysulfide
Sulfur
55-gallon drums
Price
$0.3 1/lb delivered
($0.682 /kg)
$0. 17 /lb delivered
($0.374 /kg)
$33 per barrel delivered
Reference
Gragg (2004)
Bubb (2004e)
Ten Siethoff (2004c)
Comments
LA Chemical
Georgia Gulf Sulfur
The costs and the chemical forms of the reagents in the Option C Process constitute proprietary
information. Table 4-7 lists the materials used in the process and their costs. Note that the drums in
which mercury is treated are 22 gallons for this cost estimate. The drum size was reduced so that the
treated mercury filled 90% of the container volume, meeting the monofill requirement. The mass of
waste product is 5.66 kg/kg of treated Hg.
Staff salary costs and utility costs for the treatment process are estimated on the process diagram.
These costs are included in the annual O&M costs for the treatment process. Staff salary is based on
information from Salary.com, and the number and type of staff required were provided by the vendor.
4.1.2.4 Cost Input Factors Common to All Treatment Technologies
Total capital costs are estimated as a percentage of the costs for the major equipment; that is,
elements of the total capital cost are calculated by multiplying factors that are applied total major
equipment costs. The factors used are shown in Table 4-8. The bases for the factors are given in the
notes under the table.
4.1.2.5 Operating and Maintenance Costs
Direct operating costs for treatment (and macroencapsulation) are estimated on the Process Diagram
sheets included in Attachments C and D (for Options A and B). The costs for Option C were calculated
in the same way. Flask disposal costs ($0.44 per kilogram of mercury processed) included in the
treatment O&M are based on Bethlehem (2001). Costs, overhead, fees, and contingency are based on
factors that are shown in Table 4-9. The bases for the factors are given in the notes under the table.
4-12
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Mercury Environmental and Economic Study
Final Report April 2005
Table 4-6. Major Equipment for the Option C Process
Component
Drum Mixer
Drum Truck
Mixing and
Handling Device
Lift/Hopper/Feeder
Reagent 3 and 4
Pumps
Reagent 3 and 4
Feed Valves
Crane
Ventilation System
Ducts
HEPA Filter
Carbon Filter
Blower
Forklift
Price
$1,404
$321
$3,725
$8,385
Pump
$2,400
Electric Motor
$1,187
Total: $3,587
$760
$78,000
$506.47 per 100 ft2.
Total= $5,065
$306.50
$47.25
Fan
$4,800
Electric Motor
$1,187
Total: $5,987
$25,000
Reference
MSC (2004)
pg. 4481
MSC (2004)
pg.3196
NA
Flexicon (2004)
RES (2002) account
100-280, page 2
RES (2002) account
100-653, page 2
RES (2002) account
15-47, page 27
RES (2002) account
100-495, page 4
RES (2002) account
15-9, page 1
Grainger (2004)
Grainger (2004)
Fan
RES (2002) account
100-1 10, page 2
RES (2002) account
100-653, page 2
Solis (2004)
Comments
TEXP Mixer
1.5 HP
Steel Deck Platform Truck
2,500 Ib
30"x60"x40"
Use the Mixer and Truck items above plus
a $2,000 allowance for customization of
the assembly (e.g. frame, brakes, track).
Flexicon
Stainless Steel, 50 cubic ft / hr
10 ft long, 4.5" OD
Pump
Vertical Split Case Centrifugal Pump
Max operating pressure 285 psi
50 gpm and 200 ft of head, 7.5 HP
Electric Motor
7.5 HP AC Motor
Stainless Steel Gate Valves, Screwed
2-inch Sch 40
Overhead traveling bridge crane, Floor
operated
3 ton, 75 foot span
24 GA ductwork (20" diameter), 1000 ft2
Air Handler HEPA Air Filter
1,100 CFM, 24"x24"xll.5", 99.97%
efficient
Activated Carbon Disposable Filters
250 FPM, 24"x24"x2"
Fan
Vaneaxial Fan
44-inch diameter 1 - 30 HP
15,000 -47,000 CFM
Electric Motor
7.5 HP AC Motor
4,000-6,000 Ib capacity
Electric Drive
Note: price gives the costs for one piece of equipment.
Table 4-7. Material Costs for the Option C Process
Component
Reagents
22 -gallon drums
Price
Proprietary
$33 per barrel delivered
Reference
Ten Siethoff
(2004c)
Comments
Assume, since not a
standard barrel size, that
the barrels will cost the
same as 5 5 -gallon
barrels.
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Mercury Environmental and Economic Study
Final Report April 2005
Table 4-8. Factors Used to Estimate Fixed Treatment Facility Capital Costs
Cost Element
Allowance for equipment not yet identified
Building site preparation
Building construction, services installation
Cost to install major equipment
Piping
Structural foundations (steel, concrete)
Electrical
Instruments
Auxiliaries
Other field expenses
Engineering
Initial start-up costs
Fees, overhead, and profit
Contingency
Factor Used in Cost Estimate
Minimum
0.10
0.08
0.26
0.39
0.30
0.28
0.08
0.13
0.48
0.35
0.35
0.02
0.09
0.39
Best
0.15
0.15
0.305
0.41
0.345
0.28
0.125
0.13
0.515
0.39
0.39
0.13
0.13
0.39
Maximum
0.20
0.22
0.35
0.43
0.39
0.28
0.17
0.13
0.55
0.43
0.43
0.24
0.17
0.39
Note
1
2
2
2
2
3
2
2
2
2
2
4
2
2
Notes:
Based on guidance in Perry and Green (1997). Minimum and Maximum reflect the range given in the reference,
Best is the average of those values. The costs for Major Equipment are multiplied by the factor to make an
allowance for equipment not yet identified.
From Table 9-51 of Perry and Green (1997) for solids-fluid processing. Minimum and Maximum reflect the range
given in the reference table, Best is the average of those values. Costs are estimated by multiplying the Major
Equipment + Allowance costs by this factor.
From Table 9-51 of Perry and Green (1997) for fluid processing. Minimum and Maximum reflect the range given in
the reference table, Best is the average of those values. Costs are estimated by multiplying the Major Equipment +
Allowance costs by this factor.
Initial start-up costs are taken from Equation 9-260 of Perry and Green (1997). The Direct Plant costs are multiplied
by this factor to estimate start-up costs. Minimum and Maximum values reflect possible ranges for the newness of
the process, newness of the equipment, the labor quality, and the interdependency of steps in the process. The Best
factor is an average of the Minimum and Maximum.
Table 4-9. Factors Used to Estimate Treatment and Macroencapsulation O&M Costs
Cost Element
Maintenance and Repair
Insurance
Property tax
Other overhead
Fee
Contingency
Factor Used in Cost Estimate
Minimum
0.02
0.01
0.02
0.055
0.20
0.39
Best
0.06
0.01
0.02
0.055
0.20
0.39
Maximum
0.10
0.01
0.02
0.055
0.20
0.39
Note
1
1
1
2
o
J
4
Notes:
1. Percentage of the major equipment costs (including the allowance for equipment not yet identified) for the treatment
or macroencapsulation facility based on guidance in Perry and Green (1997).
2. Percentage of the direct plus indirect costs based on guidance in Perry and Green (1997).
3. Percentage of the direct plus indirect costs based on vendor information for similar process.
4. Percentage of the direct plus indirect costs based on guidance in Perry and Green (1997) for capital costs.
4.1.3 Macroencapsulation
ARROW-PAK macroencapsulation is a process offered by Boh Environmental that places waste into
steel drums that are then sealed inside HOPE pipe (DOE 2002; USEPA 2002d). As part of the three
treatment processes considered here, the waste is placed in drums. The macroencapsulation process adds
the following steps:
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Mercury Environmental and Economic Study
Final Report April 2005
1. The drums are placed into ARROW-PAK tubes (HDPE pipe) using a forklift fitted with a plunger
and a purpose-built loading rack.
2. The ARROW-PAK tubes are sealed at both ends with HDPE endcaps that are fused to the pipe.
Attachments C and D (for Options A and B respectively) each include a diagram for the
macroencapsulation process that shows the equipment and materials used for the macroencapsulation cost
estimates . The macroencapsulation costs for Option C were calculated similarly. While the major
equipment used for the macroencapsulation process is the same for every mercury treatment process, the
material quantities vary with the amount of waste produced by each process. This section describes the
assumptions and sources of information shown on the macroencapsulation process diagram.
Table 4-10 lists the major equipment and costs for the macroencapsulation process. The cost of the
major equipment is used to estimate the overall capital costs for the macroencapsulation process. The
materials' costs for macroencapsulation are listed in Table 4-11.
Table 4-10. Major Equipment for Macroencapsulation
Component
Crane
Waste loading
rack
Fusion equipment
Chocks
Forklift
Price
$78,000
$2,400
$3,500
$43
$25,000
Reference
RES (2002) account
100-495, page 4
Global Industrial
(2004)
MSC (2004) pg 962
Grainger (2004) pg
2346
Solis (2004)
Comments
Overhead traveling bridge crane, Floor
operated
3 ton, 75 foot span
Increased costs of commercial pallet racks to
account for customization required for this
application.
Assume capital required is similar to arc
welding machine
4,000-6,000 Ib capacity
Electric Drive
Note: price gives the costs for one piece of equipment.
Table 4-11. Material Costs for Macroencapsulation Process
Component
Arrow-Pak tubes
Arrow-Pak endcaps
Price
$45/foot
$250 per endcap
Reference
Bubb (20041)
TenSiethoff(2004d)
Comments
Estimated as HDPE pipe
Estimated as HDPE endcaps
As with the treatment facility capital costs, total capital costs are estimated as a percentage of the
costs for the major equipment. The factors used for a macroencapsulation facility at a fixed site are
shown in Table 4-12. The bases for the factors are given in the notes under the table.
Staff salary costs and utility costs for the macroencapsulation process in Options A and B are
estimated on the process diagrams in Appendices C and D. These costs are included in the annual O&M
costs for macroencapsulation. The costs for Option C are calculated similarly. Staff salary is based on
information from Salary.com.
4.1.4 Mobile Treatment
The size of the treatment facilities for the centralized alternative is such that it is perfectly feasible to
skid mount them and transport them from site to site. The base case alternative is one in which there is a
single mobile facility capable of treating 1,000 MT per year that is moved from site to site as needed.
Potential alternatives are ones with somewhat smaller capability (say 500 MT/year or 330 MT/year) so
that mercury can be treated at more than one site at once.
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Mercury Environmental and Economic Study
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Facility relocation costs are estimated as the sum of the following: transportation of equipment,
assembling the treatment facility, start-up, and contingency. The sum is the cost for one move. Total
costs over the span of processing will depend on the number of facility relocations that occur.
Table 4-12. Factors Used to Estimate Fixed Macroencapsulation Facility Capital Costs
Cost Element
Allowance for equipment not yet identified
Building site preparation
Building construction, services installation
Cost to install major equipment
Other field expenses
Engineering
Initial start-up costs
Fees, overhead, and profit
Contingency
Factor Used in Cost Estimate
Minimum
0.10
0.08
0.26
0.19
0.10
0.35
0.02
0.30
0.26
Best
0.15
0.15
0.305
0.21
0.11
0.39
0.13
0.315
0.26
Maximum
0.20
0.22
0.35
0.23
0.12
0.43
0.24
0.33
0.26
Note
1
2
2
o
J
o
J
4
5
o
J
o
3
Notes:
1. Based on guidance in Perry and Green (1997). Minimum and Maximum reflect the range given in the
reference, Best is the average of those values. The costs for Major Equipment are multiplied by this
factor to make an allowance for equipment not yet identified.
2. Considered as additional space that would be added to the building used for treatment. Factor is from
Table 9-51 of Perry and Green (1997) for solids-fluid processing. Minimum and Maximum reflect the
range given in the reference table, Best is the average of those values. Costs are estimated by
multiplying the Major Equipment + Allowance costs by this factor.
3. Used factors from Table 9-51 of Perry and Green (1997) for solids processing. Minimum and Maximum
reflect the range given in the reference table, Best is the average of those values. Costs are estimated by
multiplying the Major Equipment + Allowance costs by this factor.
4. Used factors from Table 9-51 of Perry and Green (1997) for solids-fluid processing. Minimum and
Maximum reflect the range given in the reference table, Best is the average of those values. Costs are
estimated by multiplying the Major Equipment + Allowance costs by this factor.
5. Initial start-up costs are taken from Equation 9-260 of Perry and Green (1997). The Direct Plant costs
are multiplied by this factor to estimate start-up costs. Minimum and Maximum values reflect possible
ranges for the newness of the process, newness of the equipment, the labor quality, and the
interdependency of steps in the process. The Best factor is an average of the Minimum and Maximum.
As with the fixed facility capital costs, total capital costs for mobile treatment are estimated as a
percentage of the costs for the major equipment. The Factors used are shown in Table 4-13. The bases
for the Factors are given in the notes under the table. The category for Other Field Expenses, which was
included in capital costs for the fixed facility, has been deleted since those costs are associated with
construction of a fixed facility. Costs for transportation of equipment between locations for mercury
treatment have not been estimated. They are assumed to be contained within the uncertainty bands on the
O&M cost estimates (see Section 4.2).
Assembling the treatment process lines is estimated to cost 1/3 as much as installing equipment in a
fixed facility. The cost to install equipment in a fixed facility is based on a percentage of the major
equipment costs. Costs for macroencapsulation facility assembly following moves are assumed to be
negligible.
Start-up of the facility is estimated to cost 1/10 as much as the initial start-up costs for the mobile
facility, which are given as part of the capital costs.
Contingency is estimated as a percentage of the rest of the facility relocation costs (the factor is 0.39)
based on guidance in Perry and Green (1997) for capital costs.
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Mercury Environmental and Economic Study
Final Report April 2005
Table 4-13. Factors Used to Estimate Mobile Treatment Facility Capital Costs
Cost Element
Allowance for equipment not yet identified
Steel for skids
Cost to assemble major equipment skids
Piping
Electrical
Instruments
Auxiliaries
Engineering
Initial start-up costs
Fees, overhead, and profit
Contingency
Factor Used in Cost Estimate
Minimum
0.10
0.28
0.26
0.30
0.08
0.13
0.48
0.70
0.02
0.09
0.39
Best
0.15
0.28
0.273
0.345
0.125
0.13
0.515
0.78
0.13
0.13
0.39
Maximum
0.20
0.28
0.287
0.39
0.17
0.13
0.55
0.86
0.24
0.17
0.39
Note
1
2
3
4
4
4
4
5
6
4
4
Notes:
1. Based on guidance in Perry and Green (1997). Minimum and Maximum reflect the range given in the reference,
Best is the average of those values. The costs for Major Equipment are multiplied by the factor to make an
allowance for equipment not yet identified.
2. From Table 9-51 of Perry and Green (1997). Used the factor for structural steel foundations for fluid processing
plant. Minimum and Maximum reflect the range given in the reference table, Best is the average of those values.
Costs are estimated by multiplying the Major Equipment + Allowance costs by this factor.
3. 2/3 of the factor used for installation of equipment for a fixed solids-fluid facility. Assembly of plant following
relocations is accounted for in Facility Relocation table. Costs are estimated by multiplying the Major Equipment +
Allowance costs by this factor.
4. From Table 9-51 of Perry and Green (1997) for solids-fluid processing. Minimum and Maximum reflect the range
given in the reference table, Best is the average of those values.
5. Double the factor used for engineering for a fixed facility. Costs are estimated by multiplying the Major Equipment
+ Allowance costs by this factor.
6. Initial start-up costs are taken from Equation 9-260 of Perry and Green (1997). The Direct Plant costs are multiplied
by this factor to estimate start-up costs. Minimum and Maximum values reflect possible ranges for the newness of
the process, newness of the equipment, the labor quality, and the interdependency of steps in the process. The Best
factor is an average of the Minimum and Maximum.
For the mobile treatment alternative, the macroencapsulation module is also mobile. As with the
treatment facility capital costs, total capital costs are estimated as a percentage of the costs for the major
equipment. The factors used are shown in Table 4-14. The bases for the factors are given in the notes
under the table.
4.1.5 Content of Appendices C and D
Appendices C and D contain detailed input to the cost estimates for two of the three treatment
technologies: Option A and Option B. There is a similar Appendix for Option C but, since it contains
proprietary information, it is not included here. Each Appendix contains:
• Treatment Process Diagrams that also double as worksheets that estimate cost of equipment, costs
of reagents, waste volume, staff, etc.
• A table of treatment capital costs for fixed facilities
• A table of treatment capital costs for mobile facilities
• A table of treatment O&M costs
• A table of facility relocation costs
• Macroencapsulation diagrams that also double as worksheets
• A table of macroencapsulation capital costs for fixed facilities
• A table of macroencapsulation capital costs for mobile facilities
• A table of macroencapsulation O&M costs
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Mercury Environmental and Economic Study
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Table 4-14. Factors Used to Estimate Mobile Macroencapsulation Facility Capital Costs
Cost Element
Allowance for equipment not yet identified
Cost to assemble major equipment skids
Other field expenses
Engineering
Initial start-up costs
Fees, overhead, and profit
Contingency
Factor Used in Cost Estimate
Minimum
0.10
0.127
0.10
0.35
0.02
0.30
0.26
Best
0.15
0.14
0.11
0.39
0.13
0.315
0.26
Maximum
0.20
0.153
0.12
0.43
0.24
0.33
0.26
Note
1
2
3
4
5
3
3
Notes:
1. Based on guidance in Perry and Green (1997). Minimum and Maximum reflect the range given in the reference,
Best is the average of those values. The costs for Major Equipment are multiplied by this factor to make an
allowance for equipment not yet identified.
2. 2/3 of the factor used for installation of equipment for a fixed solids processing facility. Assembly of plant
following relocations is accounted for in Facility Relocation table. Costs are estimated by multiplying the Major
Equipment + Allowance costs by this factor.
3. Used Factors from Table 9-51 of Perry and Green for solids processing. Minimum and Maximum reflect the range
given in the reference table, Best is the average of those values. Costs are estimated by multiplying the Major
Equipment + Allowance costs by this factor.
4. Used factors from Table 9-51 of Perry and Green (1997) for solids-fluid processing. Minimum and Maximum
reflect the range given in the reference table, Best is the average of those values. Costs are estimated by multiplying
the Major Equipment + Allowance costs by this factor.
5. Initial start-up costs are taken from Equation 9-260 of Perry and Green. The Direct Plant costs are multiplied by this
factor to estimate start-up costs. Minimum and Maximum values reflect possible ranges for the newness of the
process, newness of the equipment, the labor quality, and the interdependency of steps in the process. The Best
factor is an average of the Minimum and Maximum.
4.2 Monofill
For all scenarios in this cost estimate except long-term storage, treated mercury will be disposed of in
a monofill. The monofill is a single purpose landfill: only treated mercury will be placed in it. Since it
will hold waste containing mercury, the monofill will be designed, constructed, and operated as a
hazardous waste disposal facility.
4.2.1 Monofill Requirements per Code of Federal Regulations
The bases for requirements that will affect the monofill are taken from 40 CFR Part 264 (CFR 2004).
These requirements are summarized below.
Design Features
The monofill will require a double liner on the bottom, a final cover that includes a top liner, a
leachate collection and removal system, and a leak detection system (§264.301). The secondary part of
the bottom liner must be composite (soil or clay plus a membrane), with a three foot thick soil/clay
component. The top liner is installed upon closure of each fill cell. The top liner must minimize liquids
that migrate into the landfill, promote drainage away from the sealed landfill, and include cover to protect
the liner (§264.310).
The monofill must have a run-on control system that prevents water from flowing onto the active
portion of the fill during a storm. The monofill also must have a run-off control system to collect water
that falls into the fill during storms. Both systems require facilities to empty water out following storms.
Construction Quality Assurance
A Construction Quality Assurance (CQA) program will be required (§264.19). This entails preparing
a written CQA plan developed and implemented by a registered Professional Engineer. Testing and
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Mercury Environmental and Economic Study Final Report April 2005
inspections are required to ensure that construction materials and installed unit components meet the
design specifications. Sufficient observations, testing, measurement, and inspections are required to
ensure:
• Structural integrity of foundations, dikes, soil liners, geomembranes, leachate collection and
removal systems, and leak detection systems;
• Proper construction according to design specifications and permits; and
• Conformity of materials with design and material specifications.
The CQA program will also require test fills for compacted soil liners to ensure the liners meet
requirements, or data showing the liner will work in the site conditions.
Special Requirements for Containers
Containers must be at least 90% full when placed in the landfill (§264.315).
Waste Analysis
If the landfill is located at a different site than is the waste treatment facility, the landfill operator
must inspect or analyze each shipment to ensure it matches the manifest (§264.13).
Security
The facility must be secured with 24-hour surveillance or a fence and gate attendant (§264.14).
Personnel Training
Personnel who work at the landfill must undergo hazardous waste handling training (§264.16).
Monitoring and Inspection
During construction, the liners must be inspected to ensure their integrity (§264.303). While in
operation (filling), the landfill must be inspected weekly and after storms to detect:
• Problems with the run-on and run-off control systems,
• Problems with the leachate collection and removal system, and
• Leaks as shown in the leak detection system.
If leakage rates increase above the "actionable level", then a response is required (§264.304).
Post-Closure Care
The final cover will have to be maintained to ensure its integrity and effectiveness. Repairs may be
necessary to correct the effects of settling, erosion, or other events (§264.310).
The leachate collection and removal system must be operated until leachate is no longer detected. Once
the final cover is installed, the leak detection system will have to be checked monthly to ensure that no
leaks are occurring. If leak rates are slow enough, the interval can eventually be increased to semi-annual
inspections. If leakage rates increase above the "actionable level", then response is required (§264.303).
A groundwater monitoring system must be maintained and monitored.
Post-closure care must continue for thirty years after the monofill is closed (§264.117).
4.2.2 Monofill Cost Bases
Monofill costs are estimated for the various treatment scenarios. Costs are estimated based on a
disposal cell that is sized to hold five years' worth of treated mercury. Since the processes assumed for
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these cost estimates treat 1,000 tons of mercury per year, each cell holds 5,000 tons. Consequently, the
cost estimates for 25,000 ton scenarios have five monofill cells.
For centralized treatment, it is assumed that the treatment facility and monofill are located at a
commercial site that already has landfills. Thus, the operator of the existing landfill can readily apply for
expansion to include the monofill. Similarly, for the mobile treatment case, the waste (in drums or tubes)
is transported to a centralized monofill at a site where the operator already has landfills. In both cases,
existing buildings are assumed to be available for administrative and other uses associated with the
disposal cells for treated mercury.
The monofill design, construction, operation, and post-closure care are based on the requirements of
40 CFR Part 264 which are listed in Section 4.2.1. How the requirements are incorporated in the landfill
design envisioned for the cost estimate is discussed below.
General Design Features
For the fixed treatment facility alternative, it is assumed that a monofill will be located at the
treatment site. For the mobile facility alternative, it is assumed that material will be transported to a
centralized monofill following treatment.
For the purposes of the estimate, it is assumed that the monofill will be divided into cells that are
large enough to hold five years' worth of treated waste. The size of the cells will vary depending on
whether the waste is placed in drums or macroencapsulated in Arrow-Pak tubes. The number of drums or
tubes per year (and thus the size of the cell) is calculated based on the assumptions for each scaled-up
treatment process. Figure 4-4 shows a plan and cross-section view for a monofill cell.
The exact design requirements will depend on Factors such as the weather, hydrology, soil conditions,
and topography of the landfill site. The design used for this cost estimate includes features identified for
a hazardous waste landfill by USEPA (2003), Geoengineers (2004), Jones (2003), Rocky Mountain
Arsenal (2004), and DPRA (1998). This design meets the CFR requirements discussed in Section 4.1.5.1.
As required by the CFR, each monofill cell will have the following features:
- Run-on controls in the form of a 6-foot high berm,
- Run-off controls in the form of a 6-foot deep drainage ditch,
- A two layer bottom liner,
- A top liner once the cell is closed, and
- Groundwater monitoring wells.
Disposal Volume Excavation
The landfill is constructed such that half the waste volume is below existing grade, and the remainder
is built-up in a mound above grade. The required volume of material to be excavated for each cell is
based on the assumed depth and required cell area.
Run-on and Run-off Controls
Each monofill cell will be surrounded by a run-on control berm and run-off control ditch. The
excavation volume is based on a 6-foot deep, trapezoidally shaped ditch with a 1-foot wide base. The
berm is assumed to be 6-feet high.
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Elevation
View
Waste
Existing grade level
Plan View
Run-off control ditch
Top and
Bottom Liner
Run-on control berm
(6 ft high)
Run-off control ditch
(6 ft deep)
•Waste fill
area
Run-on control berm
Figure 4-4. Landfill Cross-Section and Plan Design
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Top soil (1 ft thick) with
etative stabilization
Geotextile filter fabric
Synthetic membrane with
geotextile support fabric
on top and bottom to
protect the HOPE (60 mil)
Compacted fill soil (2 ft thick)
Gravel drainage layer
(1 ft thick) and leachate
collection and removal _
piping
Gravel drainage
(1 ft thick) and leak
detection piping
Compacted fill soil (3 ft thick)
Gravel drainage layer
' (6 in thick)
Compacted clay
(1.5 ft thick)
Top
Liner
6 ft thick
Waste with flowable fill
around drums/tubes
(15 ft thick)
> Waste
15 ft thick
Geotextile filter fabric
Synthetic membrane with geotextile
^^-^ support fabric on top and bottom to
^ protect the HOPE (60 mil)
Synthetic membrane with geotextile
support fabric on top to protect the
HOPE (60 mil)
Compacted clay
' (3 ft thick)
Bottom
Liner
7 ft thick
Figure 4-5. Landfill Liner Cross-Section
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Waste and Fill Layer
Two feet of compacted fill soil will protect the primary bottom liner from damage during placement
of the waste containers. As waste is placed in the monofill, a flowable fill will be placed around the
drums or tubes. The fill will be treated to the desired pH for the waste. The waste layer will be fifteen
feet thick.
It is assumed that 10% of the disposal volume will be filled with flowable fill. The flowable fill unit
cost is based on the value for compacted clay.
Top Liner
Once the waste layer is full, a cover will be placed to close the cell. This top cover will consist of a
composite liner with 1.5 feet of compacted clay and a HDPE membrane. Geotextile support fabric will
sandwich the HDPE to protect it. A gravel drainage layer will promote drainage of rain away from the
sealed fill cell. Geotextile filter fabric will prevent fill soil from clogging the drainage layer. Top soil
will be placed above compacted fill soil that will protect the top cover. Vegetation will be planted to
prevent erosion of the top soil and fill soil.
Groundwater Monitoring Wells
Each fill cell will have four groundwater monitoring clusters (one upgradient cluster and three
downgradient based on the design in DPRA (1998). Each cluster consists of three wells.
Construction Quality Assurance
For the cost estimate, the CQA Program will add to construction expenses. This additional cost is
meant to cover all observations, tests, measurements, and inspections required during construction to
assure quality.
Special Requirements for Containers
All three treatment processes considered in this estimate will fill containers at least 90% full, so the
CFR requirement will be met.
Waste Analysis
It is assumed that the operator of the landfill will be able to inspect markings on the outside of the
drums or tubes to verify the contents of the containers. Quantities of these barrels or tubes will easily be
checked by the logistics personnel when shipments of waste arrive. The chemical analysis of the waste
that occurs at the treatment facility will serve as the analysis for the landfill also.
Equipment
Since the monofill is located at an operating landfill site, all equipment necessary for handling waste
and fill is assumed to be available. This equipment may include cranes, front end loaders, and flowable
fill equipment. No costs are charged to the monofill to purchase, operate, or maintain this equipment.
Security and Personnel Training
It is assumed that the landfill will be constructed at a site that already has a security system, so this
cost will not be included in the estimate. It is also assumed that the personnel who work the new landfill
will already have hazardous waste training.
Staffing
Since the monofill will be located at a site that already has landfills, the staff available at the site will
be utilized for monofill operations (during filling). The charges for landfill site staff time will depend on
the volume of waste delivered from the treatment process and the frequency that waste is shipped to the
monofill. The staff that will be utilized is assumed to consist of:
- Four Operators,
- One Maintenance Technician,
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- One Logistics and Shipping Clerk,
- One Operations Supervisor,
- One Administrative Assistant,
- One Plant Manager,
- One QA/Health/Safety Coordinator.
Monitoring and Inspection
During construction, the liners will be inspected as part of the CQA Program. The run-off, run-on,
LCRS, and LDS will be inspected weekly during operations (filling). The cost of these inspections is
included in the charges for the QA, Health, and Safety Coordinator.
Leachate Treatment
While in operation (filling), the LCRS will collect rain water that falls in the open cell. It is assumed
that this leachate will not require treatment.
Utilities
Utilities are assumed to be an annual cost for each cell during filling operations. Once cells are
closed, the utilities are assumed to be negligible.
Post-Closure Care
The post-closure care period will be 30 years following closure of each landfill cell.
It is assumed that the LCRS will require monthly inspections for five years following closure. Five
years after cell closure, it is assumed that no more leachate will appear and that inspections are not
required. Each inspection is assumed to require a day of an operator's time.
The LDS is assumed to require monthly inspections until 5 years after closure, then semi-annual
inspections for the remainder of the 30-year post-closure care period. Each inspection is assumed to
require a day of an operator's time.
It is assumed that ground water samples will be required monthly from each well while cells are being
filled, and then semi-annually for the 30-year post-closure care period.
Permits and Bonding
Permits are assumed to be an annual cost for the entire operation and post-closure period for each
landfill cell.
Bonding is assumed to be an annual cost for the entire operation and post-closure period for each
landfill cell.
Assumptions on Failures, Leakage Rates, and Corrective Actions
Since the costs for catastrophic failures and corrective actions are difficult to estimate and could be
high, the following assumptions will be made:
- It is assumed that no problems will be found during operation (filling) that require repairs or
remediation.
- Leakage rates are assumed to remain below "actionable levels", so that repair and remediation
is not required during the life of the monofill.
- It is assumed that no ground water problems occur that require repair of the monofill.
- It is assumed that no catastrophic failure of the containment system occurs that requires
emergency repair.
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4.2.3 Monofill Costs
Tables showing the build up of the cost estimates are provided in Appendices E, F, and G for
monofills that take treated mercury from the Option A, Option B, and Option C processes, respectively.
Each of the Appendices contain the following:
• A table of monofill dimensions
• A table of labor and materials costs during construction
• A table of O&M costs during filling
• A table of post-closure O&M costs
Engineering
Engineering costs are estimated as being 10% of the Construction costs (DPRA 1998).
Construction
Construction costs are the sum of Labor and Materials, Inspection and Testing, Quality Assurance,
Other Field Expenses, Fee, and Contingency. Inspection and Testing, Quality Assurance, and Other Field
Expenses are estimated as percentages of the labor and material costs. The Fee and Contingency are
estimated as percentages of the sum of all other Construction costs. The factors, taken from DPRA
(1998), are shown in Table 4-15.
Table 4-15. Factors Used to Estimate Monofill Construction Costs
Cost Element
Inspection and Testing
Quality Assurance
Other Field Expenses
Fee
Contingency
Factor Used in Cost Estimate
0.05
0.15
0.05
0.15
0.10
Operating and Maintenance During Filling
Operations and Maintenance costs during filling are assumed to be made up of the following
categories: Permits, Bonding Insurance, Direct O&M Costs, and Contingency. Permits cost $10,000 per
year (DPRA 1998). Bonding Insurance is assumed to cost $10,000 per year. Direct O&M Costs are
calculated in a separate table; the subtotal is given in the Summary table. Per DPRA (1998) Contingency
is 10% of the other O&M costs.
An annual total is given for O&M during filling. The subtotal for O&M during filling sums the
annual total for the number of years treated mercury is sent to the monofill: 5 years for 5,000 tons,
12 years for 12,000 tons, and 25 years for 25,000 tons.
Operating and Maintenance Post-Closure
Operating and Maintenance costs for the 30 years after each monofill cell is closed are given in
Appendices E, F, and G. Details of the estimate are given in the O&M (post-closure) table. The O&M
(post-closure) table gives the costs for one cell. Consequently, the summary table results for scenarios
that require more than one cell are multiples of the O&M (post-closure) table total.
Miscellaneous
The size of the monofill cell is a key parameter for estimation of labor and materials costs. The
Dimension tables in Appendices E, F, and G give the size of a five year monofill cell for each treatment
process. The size of the cell is set by the number of barrels of treated mercury the five year cell must
accept. Dimensions are calculated for disposal of treated mercury in barrels and in Arrow-Pak tubes.
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The monofill is assumed to be shaped as shown in Figure 4-4, with a square or rectangular plan. The
cross-sections at the edges of the cells have 45-degree slopes. Volumes and areas for cost estimation are
approximated using these shapes and the lengths of the cell sides.
The cost estimates for labor and materials are based on the size of the five year cell and the unit costs
for the materials and construction activities. All unit costs are installed costs based on DPRA 1998.
Since this reference has 1998 prices, the costs have been escalated 12%20 to account for inflation between
1998 and 2004 (USDOL 2004).
Direct Operating and Maintenance costs during filling are calculated in the Direct O&M (filling)
tables in Appendices E,F, and G. The total from this table is used in the Summary table. The direct costs
are composed of the following: salary for staff, costs for groundwater monitoring tests, utilities, and the
fee. Salary for staff is based on an estimate of the time required to accept shipments of treated mercury.
The number of shipments is calculated based on the amount of waste produced per year, the weight each
truck can transport, and the amount of room available on each truck. The number of shipments is
calculated for treated mercury in barrels and for waste macroencapsulated in Arrow-Pak tubes. Annual
utilization of the staff is calculated as the ratio of shipments to shifts the staff works (based on a five-day
work week). The burdened salary for staff is taken from Salary.com.
The cost for groundwater monitoring tests is based on costs given in DPRA (1998). The costs have
been inflated 12% to account for inflation between 1998 and 2004 (USDOL 2004).
Utilities are assumed to cost $10,000 per year while the monofill is in operation (being filled).
The fee is 15% of the sum of the other operating and maintenance costs.
The O&M (post-closure) sheets in Appendices E, F, and G gives the total costs for operating and
maintenance for a 30-year post-closure period. These costs are made up of the following parts: LCRS
monitoring, LDS monitoring, ground water sample analysis, utilities, contingency, license and bonding
costs, and the fee.
LCRS and LDS monitoring costs are a function of the time spent monitoring the systems per year and
the costs for operators' time to perform the monitoring. Each inspection is assumed to take one day of an
operator's time. The cost for a day of an operator's time is estimated as a function of the burdened salary
for the operator.
The cost for groundwater monitoring tests is based on costs given by DPRA (1998). The costs have
been inflated 12% to account for inflation between 1998 and 2004 (USDOL 2004).
Utilities are assumed to cost $1,000 per year after the monofill cell is closed. License and bonding
fees are assumed to cost $10,000 per year after the monofill cell is closed.
The fee is 15% of the sum of the post-closure operating and maintenance costs. Contingency is
calculated as 10% of the post-closure operating and maintenance costs plus fee.
4.3 Storage
This section first lays out assumptions for calculating the costs of the long-term storage alternative,
and then describes assumptions for the costs associated with the treatment alternatives. The basic input
data are derived from Appendix D of the MMEIS (DLA 2004). For example, the MMEIS estimates the
annual cost of storing 2,617 MT of elemental mercury at the Somerville Depot to be $404,495. This is
made up of two parts, utility costs of $4,945 and rental of $400,000, based on 43,200 ft2 at an annual rent
of $1.76/ft2. Routine maintenance of the warehouse is assumed to be included in the rent. Other labor,
such as walking down the stockpile and taking occasional mercury vapor concentration measurements, is
assumed to be negligible. Thus, the cost of storage of 1 MT at Somerville for 1 year is $404,495/2617 =
$154. The average cost of storage at all DLA facilities (except the Y-12 facility) is $147/MT/yr. In the
calculations reported below, the cost of storage is simply calculated by multiplying the amount of
elemental mercury in storage in a particular year by $147, discounting to obtain NPV, and summing over
all years of storage.
' Using Producer Price Index average for 1998 versus the average through August 2004.
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4.3.1 Long-Term Storage
This subsection describes the bases and assumptions for long-term storage of elemental mercury for
the three mass alternatives.
Alternative 1 - 5,000 MT
Alternative 1 is quite close to the status quo at DNSC locations. Therefore, Alternative 1 is costed as
if storage will continue there for 35 years. On a non-discounted basis, 5,000 MT would therefore cost
5,000x147 = $735,000/year.
Alternative 2 - 12,000 MT
For this alternative, it is assumed, as for Alternative 1, that there is 5,000 MT of elemental mercury
in existing storage. The remaining 7,000 MT becomes available at a uniform rate over a period of
12 years, i.e., atarate of 583 MT/yr21. For the storage alternative, therefore, the amount in the stockpile
will increase by this amount each year, and additional (non-discounted costs) accrue at a rate of
583x 147 = $85,700/yr. This is in addition to the costs incurred for storing the original 5,000 MT.
Alternative 3 - 25,000 MT
For this alternative, it is assumed, as for Alternative 1, that there is 5,000 MT of elemental mercury
in existing storage. The remaining 20,000 MT becomes available at a uniform rate over a period of
25 years, i.e., at a rate of 800 MT/yr. For the storage alternative, therefore, the amount in the stockpile
will increase by this amount each year, and additional costs will accrue at a non-discounted rate of
800xl47 = $117,600/yr.
4.3.2 Storage Costs Associated with Treatment and Disposal Alternatives
The need for storage will not vanish immediately even if the waste is treated.
Alternative 1 - 5,000 MT
For the centralized treatment location, it is assumed that elemental mercury will be transported from
the current storage locations to the treatment facility at a rate of 1,000 MT per year for five years. Each
1,000 MT occupies 45,000 ft2 (~ 4,200 m2). It is assumed that storage space will be decommissioned at a
rate of 45,000 ft2 (4,200 m2) per year, and that storage costs will decrease by 1,000x147 = $147,000/yr
until all the mercury has been treated. The same rate of depletion of the existing stockpile is assumed for
the mobile treatment alternative.
Alternative 2 - 12,000 MT
When the mercury is treated at a centralized facility, it is assumed that the 583 MT/yr of "new"
elemental mercury is transported directly to the treatment facility, thus obviating the need for intermediate
storage. The remaining 417 MT/yr required to make up the assumed treatment rate of 1,000 MT/yr is
drawn down from storage. Each year, therefore, the non-discounted costs of storing elemental mercury
decrease by 417x147 = $61,300/yr for 12 years. The same rate of depletion of the existing stockpile is
assumed for the mobile treatment alternative.
Alternative 3 - 25,000 MT
When the mercury is treated at a centralized facility, it is assumed that the 800 MT/yr is transported
directly to the treatment facility, thus obviating the need for intermediate storage. The remaining
21 Note that the assumption that there is about 5,000 MT in existing storage and that additional elemental mercury becomes
available at a rate of a few hundred MT per year is consistent with data in Appendix D of the MMEIS.
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200 MT/yr required to make up the assumed treatment rate of 1,000 MT/yr is drawn down from storage.
Each year, therefore, the non-discounted costs of storing elemental mercury decrease by 200x147 =
$29,400 for 25 years. The same rate of depletion of the existing stockpile is assumed for the mobile
treatment alternative.
4.4 Transportation
This section describes the assumptions and bases for transportation costs associated with the various
treatment and storage alternatives.
4.4.1 Centralized Treatment
In the case of centralized treatment, in all scenarios elemental mercury needs to be transported to the
centralized facility at a rate of 1,000 MT per year. As noted above, it is assumed that elemental mercury
will be transported in drums (six 76 Ib (34 kg) flasks to a drum) with five drums to a pallet. Each pallet
carries almost exactly 1 MT of elemental Hg: therefore 1,000 pallets will be transported each year. If the
material is transported by road, each truck can carry up to 14 pallets or 14 MT (DLA 2004), so that there
will be 71.4 truckloads per year. If the material is transported by rail, each railcar can carry up to 28
pallets or 28 MT (DLA 2004), so there will be ~ 36 railcar shipments per year. For the purposes of the
current analysis, only full trucks or railcars will be considered. In practice, the exact number of pallets
per truck or railcar is not critical because the authors used the MMEIS (DLA 2004) to calculate a cost per
ton-mile of elemental mercury transport. These costs lie in the range $0.025-$0.038/MT-mile for rail and
$0.039- 0.064/MT-mile for road. In addition to the cost per ton-mile, there is a preparation cost per ton
that covers such items as overpacking, amounting to ~ $96/MT for truck transportation and ~ $111/MT
for rail transportation.
The required transportation distances are not known because the location of the treatment facility has
not yet been identified. To gain insight into the magnitude of mercury transport costs, three "proxy" and
three existing storage depot locations were incorporated as candidate treatment facility locations. Transit
distances were then calculated to the candidate treatment sites and unit transport costs derived from the
MMEIS (DLA 2004) were applied to arrive at total transport costs. The six candidate site locations were
chosen to provide a range of potential transport distances of 150 to 2,800 miles for "legacy" mercury
stocks. Another basic assumption is be that the average transportation distance for "new" mercury is
1,000 miles and uncertainty will be accommodated by assuming that the range is 500 to 1,500 miles.
Examples of how transportation costs are calculated for the centralized treatment alternatives follow:
5,000 MT
For the 5,000 MT case the elemental mercury is all "legacy" mercury and therefore travels 150 to
2800 miles. The minimum non-discounted cost per year is to move 1,000 MT 150 miles by rail at a cost
of $0.025 per MT-mile plus $111/MT preparation costs = 1,000x150x0.025+1,000x111 = $114,750/yr.
The maximum cost is to move 1,000 MT 2,800 miles by truck at a cost of $0.064 per MT-mile and an
initial preparation cost of $96/MT = 1,000x2,800x0.064 + 1,000x96 = $275,200/yr.
12,000 MT
For the 12,000 MT alternative, there is a need to transport 417 MT of "legacy" mercury and 583 MT
of "new" mercury/year. The non-discounted annual costs for the legacy mercury are obtained by scaling
the results from the previous paragraph by 0.417 to give a range from $47,900 to $114,800/yr. The
minimum cost of transporting the "new" mercury is to move it 500 miles by rail at $0.025/MT-mile with
$111/MT preparation costs = 500x0.025x583 + 111x583 = $72,700/yr. The maximum cost is to move the
"new" mercury 1,500 miles by truck at a cost of 0.064/MT-mile and a preparation cost of $96/MT =
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1,500x0.064x583 + 96x583 = $111,900/yr. Combining the estimates for "legacy" and "new" mercury
gives a range of $120,600 to $226,700/yr.
For the centralized treatment alternatives, it is assumed that the monofill is collocated with the
treatment facility and that transportation costs for the final waste form are negligible.
4.4.2 Mobile Treatment
In the case of mobile treatment, the treatment facility travels to the mercury, so no elemental mercury
is transported. Instead, the treated waste (macro-encapsulated or not) is transported to a centralized
monofill. If it is not macro-encapsulated, it is assumed that the waste is in 55-gallon drums for the Option
A and Option B processes and 22 gallon drums for the Option C process. If it is macro-encapsulated,
55-gallon or 22-gallon drums are placed in sealed polyethylene tubes. The location of the monofill is not
specifically known, so as in the centralized treatment scenarios, three "proxy" and three existing storage
depot locations were incorporated as candidate monofill locations. Transit distances were then calculated
to the candidate monofill sites and unit transport costs derived from the MMEIS (DLA 2004) were
applied to arrive at total transport costs. The six candidate site locations were chosen to provide a range
of potential transport distances of 150 to 2,800 miles for "legacy" mercury stocks. Again, it is assumed
that the average distance to the monofill for waste forms generated from "new" mercury is 1,000 miles,
with a range extending from 500 to 1,500 miles. The costs per MT-mile for treated waste are assumed to
be the same as those for elemental mercury, so that transportation costs for mobile treatment can be
simply scaled from those for centralized treatment. Thus, for example, for Option A, 3 MT of waste are
generated for every MT of elemental mercury so, taking the 5,000 MT results from Section 4.4.1 and
multiplying by 3 gives a non-discounted cost range from $344,000 to $825,600/yr
4.4.3 Long-Term Storage - Transportation of Elemental Mercury
For the 5,000 MT alternative, it is assumed that there is already 5,000 MT of elemental mercury in
storage, so that no further transportation costs are incurred. For the 12,000 MT alternative, 583 MT of
"new" elemental mercury is transported to a centralized storage facility each year for 12 years. For the
25,000 MT alternative, 800 MT of "new" elemental mercury is transported to a centralized storage
facility each year. As above, the total transportation distance varies from 500 to 1,500 miles. For
example, the range of costs for the 12,000 MT alternative (583 MT of "new" mercury per year) has
already been calculated in Section 4.4.1 and is from $72,700 /yr to $111,900/yr.
4.4.4 Miscellaneous
There are a number of items that need to be delivered to the various sites and in principle their
transportation costs should be calculated:
• Mercury flasks and 30-gallon drums for overpacks
• 22-gallon and 55-gallon drums to contain waste
• Reagents
In practice, the costs of these items are quoted as delivered to the site, so there is no need for explicit
calculation of transportation costs.
4.5 Uncertainties
This section contains a simplified assessment of uncertainties in the costs associated with each of the
39 alternatives. The overall costs are broken down into the following categories:
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As noted at the beginning of Chapter 4, each of the thirty-six cost estimates for treatment and disposal
includes the following elements:
• Capital costs for the treatment facility,
• Capital costs for the macroencapsulation facility (if part of the alternative)
• Operating and maintenance costs for the treatment process,
• Operating and maintenance costs for the macroencapsulation process (if part of the
alternative),
• Costs associated with the mobile treatment alternative,
• Transportation costs associated with each alternative,
• Costs of storing elemental mercury prior to treatment
• Decommissioning costs for the treatment facilities,
• Monofill engineering and construction costs,
• Monofill operating costs, and
• Costs of maintaining and monitoring the monofill for a thirty-year period following its
closure.
Each of the three storage alternatives contains the costs of maintaining the existing stockpile
(assumed to be 5,000 MT) in storage, adding to storage space for the 12,000 MT and 25,000 MT cases,
and transporting elemental mercury to the storage facility(ies).
Initially, it was hoped that the uncertainties in each of these elements could be built up from
uncertainties in the costs of individual components or activities. This did prove possible for the capital
costs for fixed treatment and fixed macroencapsulation facilities. However, with the information that the
team was able to collect within the budget available for this project, this did not prove possible for the
remaining elements. Therefore, the authors adopted some simplifications, as will become clear after first
considering some relevant background information.
4.5.1 Background Information on Uncertainties in Capital Costs and Life Cycle Cost Estimates
This section provides information on construction cost uncertainties from a commercial source and
on life cycle cost estimate uncertainties from EPA.
4.5.1.1 Construction Projects/Capital Costs
Broadly speaking, there are five types of cost estimate for construction projects (Industrial Cost
Engineering 2003)
• Conceptual or order of magnitude
• Factored
• Study or preliminary
• Basis of budget
• Detailed or Firm Price Construction
Conceptual: A minimum of information is used to develop this type of "Ball Park Estimate." The
estimate is prepared from in house data available from past jobs on similar plants. A cost estimate
determined this way is only valid for a similar plant. This estimate has a probable accuracy of-50% to
+50% or worse.
A factored estimate requires that all process equipment must be priced. A factored estimate is
produced by taking the cost of individual types of process equipment, and multiplying it by an
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"installation factor" to arrive at the Total Direct Process Cost. The accuracy of this type of estimate
depends upon the definition of scope, equipment costs, and known process factors. This type of estimate
has a probable accuracy of-25% to +30%.
A study or preliminary estimate is prepared after the process engineers have completed the
conceptual design, made the equipment list by size and category, made preliminary process flow
diagrams, and when engineering is from 1% to 10% complete. The following documents serve as the
basis for this type of estimate:
• Reasonably defined equipment list by size and category, including onsite and offsite
equipment.
• Preliminary overall plot-plans.
• Know general site conditions such as location, utility requirements, site survey, utility
distribution (sewers, power feeders, etc.) labor productivity availability of skilled
workmen, and availability of construction materials.
• Overall process flow diagrams.
The probable accuracy of this type of estimate is -15% to +20%.
A basis of budget estimate is prepared after the process engineers have completed the conceptual
design, made an equipment list by size and category, made process flow diagrams, and the detail
engineering is from 25% to 50% complete. The probable accuracy of this type of estimate is -10% to
+15%.
In a detailed estimate each item is costed in a thorough manner without "eyeballing", "percentaging",
or other forms of educated guesses. This estimate is prepared after the process design has been completed
and when the detail design is 70% - 90% complete. The probable accuracy of this type of estimate is -5%
to +10%.
4.5.1.2 EPA Guidance on Uncertainty in Life Cycle Cost Estimates
EPA has produced some guidance for Life Cycle Cost Estimates for Superfund remediation activities
(USEPA 2000) - see Figure 4-6. This displays a similar pattern of declining uncertainty as the design
becomes more complete and the project moves into construction and then O&M.
4.5.2 Uncertainties in Costs of Elements of the Long-Term Disposal of Elemental Mercury
Various parts of the cost estimate for the 39 alternatives for long-term disposal of mercury are at
different stages with respect to the level of cost uncertainty.
Capital Costs for the Fixed Treatment Facilities: per the information above from the Industrial
Cost Engineering Web site, it would appear that a study or preliminary estimate is feasible because
overall process flow diagrams are available as is a reasonably defined equipment list. General site
conditions may not be known, but it is assumed that the facility will be constructed at an existing site and
that adequate utilities, labor and materials will be available. In addition, these facilities are quite simple
and it is not expected that there will be very large cost over or underestimates. Therefore, a probable
accuracy in the range -15% to + 20% is expected.
Capital Costs for Fixed Macroencapsulation Facilities: It is also expected that a study or
preliminary estimate is possible for these facilities so that a predicted range of-15% to +20% is
reasonably in accord with expectations.
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Exhibit 2-3
Expected Cost Estimate Accuracy Along the Supertund Pipeline
0 Remedial Investigation/ Remedy I
Feasibility Study & Selection I Remedial Design
Remedial Action
+100%
Screening of
Alternatives
Low
Detailed Analysis
of Alternatives /
Conceptual Design
• Level of Project Definition.
liort ^ Maintenance
•H
High
Figure 4-6. Expected Cost Accuracy Along the Superfund Pipeline: Exhibit 2-3 from EPA (2000)
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Mercury Environmental and Economic Study Final Report April 2005
Capital Costs for Mobile Treatment Facilities: this is an area of greater uncertainty. The cost of a
single mobile unit can be confidently estimated to within -15 to +20%, as for the fixed case, but what is
unknown is whether there would be a single large unit, two half-size units, or several smaller ones. The
actual cost estimates in Appendices C and D are for one large facility. One could easily envisage the
construction costs doubling or tripling if several smaller units were constructed. Therefore, the cost range
is taken to be -15% to +200%.
Capital Costs for Mobile Encapsulation Facilities: these suffer from the same uncertainties as do
the costs for the mobile treatment facilities and a similar range is assumed, -15% to +200%.
O&M Costs for Fixed Treatment and Macroencapsulation Facilities: referring to
Figure 4-2 above, the fixed treatment and macroencapsulation facilities are beyond the conceptual design
phase but clearly not at the final design phase. Interpolating between these two points on Figure 4-2
suggests that a range in these cost between - 15% and + 20% is reasonable.
O&M Costs for Mobile Treatment and Macroencapsulation Facilities: this alternative is really
still at the pre-conceptual phase and per Figure 4-2. the range of uncertainty in costs is -50% to + 100%.
Decontamination Costs for the Treatment and Macroencapsulation Facilities: 50% of capital
costs with same percentage uncertainty range.
Construction and O&M Costs for the Monofill: monofills are relatively well understood.
Referring again to Figure 4-2, the monofill is between conceptual and final design so here again a range
of cost uncertainty between -15% and + 20% is reasonable for the total Life Cycle Cost Estimate for the
monofill.
Transportation Costs: the largest uncertainty in transportation costs is not knowing how far the
mercury or the waste product will be transported. Other transportation costs are well documented in the
Mercury Management Environmental Impact Statement (DLA 2004). Transportation cost estimates and
uncertainty ranges are discussed in Section 4.4
Storage Costs: storage of elemental mercury has been studied in considerable detail in the MMEIS
and is well known. Uncertainties should be small. The authors assigned a small range from
-10% to+10%.
4.5.3 Calculation of Uncertainties
In summary, the input cost ranges for the uncertainty analysis are as follows:
• Capital costs for the fixed treatment facility and the fixed macroencapsulation facility:
bottom-up calculation (see Appendices C, D, and E) - approximately -15% to + 20%
• Capital costs for the mobile treatment facility and the mobile macroencapsulation treatment
facility:-15% to+ 200%
• Operating and maintenance costs for the fixed treatment process and the fixed
macroencapsulation process: -15% to + 20%
• Operating and maintenance costs for the mobile treatment facility and the mobile
macroencapsulation facility: -50% to + 100%
• Transportation costs associated with each alternative: see Section 4.4
• Costs of storing elemental mercury prior to treatment (or for the storage alternative): -10%
to + 10%
• Decommissioning costs for the treatment and macroencapsulation facilities: 50% of capital
costs with same percentage uncertainty range
• Monofill Life Cycle Cost Estimate: -15 % to + 20%.
These costs were assigned triangular probability distributions and were input into the Crystal Ball®
computer model for Monte Carlo simulation (Decisioneering 2004), leading to estimates of uncertainty on
the total costs of each alternative.
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4.6 Results and Interpretation
The results of the economic analysis are summarized in Tables 4-16 and 4-17. Note that the "best"
estimates are the means that result from the Monte Carlo analysis and are not necessarily exactly the same
as would result from a sum of point estimates without uncertainty distributions. Tables 4-16 and 4-17
prompt a number of observations and conclusions.
Importance of Costs of Reagents
The most striking result is that the Option C alternatives cost far more than do the others. Analysis of
the calculations reveals that there is one parameter that drives almost the whole of this difference - the
cost of reagents. For Option C, the NPV of reagent costs alone over five years is approximately $123M.
By contrast, the five-year NPV of reagents for the Option A process are approximately $8M over 5 years.
For the Option B process, NPV of reagent costs over 5 years is approximately $1.4 M. Therefore, for the
alternatives that treat 5,OOOMT, the reagent costs alone account for more than $100M difference between
the costs of Option C process and those of the Option A or Option B processes, with correspondingly
larger differences for the 12,000 MT and 25,000 MT alternatives.
The composition of the Option C reagents is proprietary. In any future decisionmaking process, the
cost per kg of treated Hg will need to be examined in more detail.
Option B - Lowest Cost
The Option B process consistently exhibits the lowest costs. As noted above, it has the lowest
reagent cost. In addition, it has the least mass increase of the three technologies - the mass multipliers for
waste form production are 1.63 (Option B), 3.26 (Option A), and 5.66 (Option C). This affects other
items such as transportation costs.
Mobile Treatment More Costly and More Uncertain
The best estimates for the NPV of alternatives that include mobile treatment are somewhat higher
than those for alternatives that include treatment at fixed facilities. In addition, the uncertainty ranges
are much wider. Both of these principally result from the wide uncertainty bands on mobile treatment
alternatives: -15% to +200% for capital costs and -50% to + 100% for O&M costs. There are also extra
costs associated with assembling and disassembling the equipment and moving it from site to site.
Narrow Range of Uncertainties for Fixed Facility Alternatives
In Table 4-16, the range of NPV numbers for fixed-facility alternatives appears to be quite
narrow, -10% to +10% or even less. The reader may fairly ask whether these ranges are too small.
To a certain extent, these narrow ranges are an artifact of the Monte Carlo analysis. The input
ranges of uncertainties are discussed in Section 4.5 and summarized in Section 4.5.3. There, the ranges
chosen for most of the inputs to the Crystal Ball® uncertainty analysis of fixed facility alternatives are in
the range -15% to +20%. It is a feature of Monte Carlo analyses that, at a given percentile level (e,g.,
95th), the 95th percentile of a sum is less than the sum of the 95th percentiles of the inputs. The more a sum
is broken down into its components, the more its 5th to 95th range of confidence is narrowed. Hence we
see in Table 4-16 (again excluding the mobile treatment cases) the predicted percentage range has been
narrowed to less than the input ranges of from -15% to + 20%.
One possible way of dealing with this would be to default to Figure 4-6. The project as a whole
lies somewhere between the "Detailed Analysis of Alternatives/ Conceptual Design" and the "Final
Design" which means that the uncertainty range could be as much as -30% to +50%, or as little as -10%
to + 15%. The reader can then make a subjective choice as to exactly where in this range of ranges the
project actually lies. Similarly, the reader might conclude that the authors have overestimated the
maturity of the input items summarized in Section 4.5.3 and that the input ranges of uncertainties should
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Mercury Environmental and Economic Study Final Report April 2005
be larger. In summary, there is a great deal of subjectivity in the uncertainty analysis and the reader is
entitled to use his or her own judgment to conclude that the ranges might well be larger.
Modest Long-Term Storage Costs
The cost of storage is relatively modest. Note that these storage costs were derived from data in the
MMEIS. For example, for continued storage of 5,000 MT for up to 35 years, the NPV is $ 11.6M.
Continuing to store elemental mercury for years or even decades is a reasonable course of action.
It is pertinent to reiterate that, as far as possible, the long-term storage and disposal alternatives are
treated on a comparable basis. All of the alternatives have storage requirements and these have been
consistently costed by taking data on storage from the MMEIS. Transportation costs have also been
treated consistently with data taken from the MMEIS. The periods of time considered are also consistent.
For example, the treatment and disposal alternatives include the time taken to fill the monofill and thirty
subsequent years of monitoring. Thus, for the 5,000 MT alternatives, costs for treatment and disposal are
taken out to 35 years (5 years to fill the monofill and 30 years of monitoring). The costs for long-term
storage of 5,000 MT of elemental mercury are also taken out to 35 years. For all alternatives, the NPV is
calculated using the same discount rate, as provided by OMB.
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Table 4-16. Net Present Value Estimates
Treatment Scenario
Treatment
Process
Option A
Option A
Option A
Option A
Option B
Option B
Option B
Option B
Option C
Option C
Option C
Option C
Macro-
Encapsulation
With
With
Without
Without
With
With
Without
Without
With
With
Without
Without
Fixed or
Mobile
Facility
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Long-Term Storage d'e
Net Present Value Estimates in Millions of Dollars
5,000 Metric Tons
Min.a
77.1
75.8
60.2
57.7
32.3
32.4
22.7
22.3
162
138
146
119
10.4
Bestb
82.7
99.2
65.4
79.8
34.3
40.9
24.3
29.3
178
203
163
184
11.6
Max.c
89.0
128
71.3
107
36.4
50.7
26.2
38.0
197
292
181
270
12.8
12,000 Metric Tons
Min.a
149
143
117
105
62.2
60.5
42.8
40.9
342
290
306
247
26.1
Bestb
161
191
128
150
66.2
78.3
46.1
54.2
378
429
341
386
29.0
Max.c
174
251
141
207
70.6
97.5
49.9
71.7
418
617
381
573
31.9
25,000 Metric Tons
Min.a
245
232
184
169
102
98.4
69.6
65.1
579
490
517
421
51.3
Bestb
265
315
203
242
109
127
75.2
87.5
639
732
578
656
57.0
Max.c
287
415
224
341
116
160
81.8
118
707
1,040
647
967
62.7
a. Fifth percentile of the distribution derived from the Crystal Ball®) analysis
b. Mean of the distribution derived from the Crystal Ball® analysis
c. Ninety fifth percentile of the distribution derived from the Crystal Ball® analysis
d. Not derived from Crystal Ball® analysis - best estimate based on MMEIS data (DLA 2004) with ±10% uncertainties
e. Cost of shipping elemental mercury to the storage location not included. Upper bound transportation costs derived from MMEIS data are $0 (5,000 MT), $1 .OM (12,000 MT),
and S2.3M (25,000 MT). These are at most small percentages of the total cost of long-term storage.
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Table 4-17. Net Present Value Estimates Expressed as Cost per Metric Ton of Treated Mercury
Treatment Scenario
Treatment
Process
Option A
Option A
Option A
Option A
Option B
Option B
Option B
Option B
Option C
Option C
Option C
Option C
Macro-
Encapsulation
With
With
Without
Without
With
With
Without
Without
With
With
Without
Without
Fixed or
Mobile
Facility
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Fixed
Mobile
Long-Term Storage
Net Present Value Estimates in Dollars
5,000 Metric Tons
Min.
15,400
15,200
12,000
11,600
6,500
6,500
4,500
4,500
32,400
27,600
29,200
23,800
2,100
Best
16,600
19,800
13,100
16,000
6,900
8,200
4,900
5,900
35,600
40,600
32,600
36,800
2,300
Max.
17,800
25,600
14,300
21,400
7,200
10,100
5,200
7,600
39,400
58,400
36,200
54,000
2,600
12,000 Metric Tons
Min.
12,400
11,900
9,800
8,800
5,000
5,100
3,600
3,400
28,500
24,200
25,500
20,600
2,200
Best
13,400
15,900
10,700
12,500
5,500
6,500
3,800
4,500
31,500
35,800
28,400
32,200
2,400
Max.
14,500
20,900
11,800
17,300
5,900
8,100
4,200
6,000
34,800
51,400
31,800
47,800
2,700
25,000 Metric Tons
Min.
9,800
9,300
7,400
6,800
4,100
3,900
2,800
2,600
23,000
19,600
20,700
16,800
2,100
Best
10,600
12,600
8,100
9,700
4,400
5,100
3,000
3,500
25,600
29,300
23,100
26,200
2,300
Max.
11,500
16,600
9,000
13,600
4,600
6,400
3,300
4,700
28,300
41,600
25,900
38,900
2,500
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Mercury Environmental and Economic Study Final Report April 2005
One difference between the treatment and disposal alternatives and the long-term storage alternatives
is that permitting costs were only considered for the former. This is because the current stockpile of
elemental mercury is not regarded as hazardous waste, and therefore hazardous waste permits are not
required. For the treatment and disposal alternatives, costs accounted for non-discounted contributions of
$10,000 per year for permitting (based on DPRA 1998) and an assumed $10,000 per year for Bonding
Insurance. If it should become the case that storage of elemental mercury requires hazardous waste
permitting and Bonding Insurance, a non-discounted amount of $20,000 per year should be added to the
long-term storage costs. The additional 5-year NPV would be approximately $90,000, a small fraction of
the $11.6M presented in Table 4-17.
In conclusion, all steps have been taken to develop costs for the alternatives on the same basis and for
this reason it is a valid observation that long-term storage costs are modest relative to the costs of
treatment and disposal.
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5.0 REFERENCES
This chapter is divided into two parts. Section 5.1 provides a complete list of references. Section 5.2 lists
those that were used in comparative analyses of Option Technologies A-F.
5.1 Complete List of References
AST 1998. Macroencapsulation of Mixed Waste Debris at the Hanford Nuclear Reservation - Final
Project Report by AST Environmental Services^ HNF-1846, Fluor Daniel Hanford, Richland, WA.
Bethlehem 2000. Bethlehem Apparatus Company Inc. The Mercury Marketplace: Sources, Demand,
Price and the Impacts of Environmental Regulations. Presented at the Workshop on Mercury in Products,
Processes. Waste and the Environment: Eliminating. Reducing and Managing Risks from Non-
Combustion Sources. Baltimore, Maryland. Sponsored by U.S. EPA. March 22-23, 2000.
Bethlehem 2001. Bethlehem Apparatus Company, Inc., Expression of Interest (for mercury processing),
Hellertown, PA. July 6, 2001.
Bjasta Atervinning 2001. Response to Defense Logistics Agency Request for Expression of Interest.
Business sensitive information removed.
Bjasta Atervinning 2002. Bjasta Atervinning Company Information, http://www.guru.se/bjasta/main.htm
BNL 2001. Brookhaven National Laboratory. Response to Defense Logistics Agency Request for
Expression of Interest.
Bowerman, B. et al. 2003. Using the Sulfur Polymer Stabilization/Solidification Process to Treat
Residual Mercury Wastes from Gold Mining Operations. (BNL-71499-2003-CP). In Society of Mining
Engineers Conference, Cincinatti, OH, February 2003.
Bubb, J., MPR Associates 2004a. Memorandum of September 16, 2004 Telecon Conversation with J.
Flatzinger, Weir Clear Liquid. Vertical Acid Pump.
Bubb, J., MPR Associates 2004b. E-mail to E. ten Siethoff, MPR Associates, September, 20, 2004.
Updated info BNL Mixer.
Bubb, J., MPR Associates 2004c. Memorandum of September 16, 2004 Telecon with N. Perillo, Mokon.
Temperature Control Systems.
Bubb, J., MPR Associates 2004d. Memorandum of September 8, 2004 Telecon with J. Meeker, Marion
Mixers. Mixer Price Quote.
Bubb, J., MPR Associates 2004e. Memorandum of September 7, 2004 Telecon with J. Maranaville,
Georgia Gulf Sulfur. Industrial Sulfur Costs.
Bubb, J., MPR Associates 2004f. Memorandum of September 10, 2004 Telecon with ERS Incorporated.
HDP E Pipe.
Butz, J. 2004. E-mail and subsequent teleconference correspondence from Jim Butz (ADA) to Geoff
Kaiser (SAIC) (and other EPA/ SAIC/ MPR staff), August 19, 2004.
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CFR2004. Standards for Owners and Operators of Hazardous Waste Treatment, Storage, and Disposal
Facilities. Title 40 Code of Federal Regulations, Part 264.
Chang, O. 2001. Hazardous and Radioactive Waste Treatment Technologies^ CRC Press.
Davis, J.D. and C.R. Osucha (Nuclear Fuel Services) 1998. Mercury Mixed Waste Treatment. In 19th
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Decisioneering 2004. www.crystalball.com.
DLA 2004. Defense Logistics Agency. Final Mercury Management Environmental Impact Statement,
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DOE 1994. U.S. Department of Energy. Gorin, A.H., J.H. Leckey, and L.E. Nulf Final Disposal
Options for Mercury/ UraniumMixed Wastes from the Oak Ridge Reservation. Y/DZ-1106.
DOE 1998a. U.S. Department of Energy. Polyethylene Macroencapsulation. Mixed Waste Focus Area.
Innovative Technology Summary Report, OST Reference No. 30. Prepared for Office of Environmental
Management, Office of Science and Technology.
DOE 1998b. U.S. Department of Energy. Macroencapsulation of Mixed Waste Debris at the Hanford
Nuclear Reservation. Final Project Report by AST Environmental Services, LLC. FINF-1846.
DOE 1999a. U.S. Department of Energy. Mercury Contamination - Amalgamate (contract with NFS and
ADA) Demonstration of DeHgSM Process. Mixed Waste Focus Area, Innovative Technology Summary
Report, DOE/EM-0471, prepared for Office of Environmental Management, Office of Science and
Technology, September 1999. http://apps.em.doe.gov/ost/itsrtmwfa.html.
DOE 1999b. U.S. Department of Energy. Mercury Contamination - Amalgamate (contract with NFS
and ADA) Stabilize Elemental Mercury Wastes. Mixed Waste Focus Area, Innovative Technology
Summary Report, DOE/EM-0472, prepared for Office of Environmental Management, Office of Science
and Technology, September 1999. http://apps.em.doe.gov/ost/itsrtmwfa.html.
DOE 1999c. U.S. Department of Energy. Demonstration ofATG Process for Stabilizing Mercury (<260
ppm) Contaminated Mixed Waste. Mixed Waste Focus Area, Innovative Technology Summary Report,
DOE/EM-0479, prepared for Office of Environmental Management, Office of Science and Technology,
September 1999. http://apps.em.doe.gov/ost/itsrtmwfa.html.
DOE 1999d. U.S. Department of Energy. Demonstration of GTS Duratek Process for Stabilizing
Mercury (< 260 ppm) Contaminated Mixed Waste. Mixed Waste Focus Area, Innovative Technology
Summary Report, DOE/EM-0487, prepared for Office of Environmental Management, Office of Science
and Technology, September 1999. http://apps.em.doe.gov/ost/itsrtmwfa.html.
DOE 1999e. U.S. Department of Energy. Demonstration of NFS DeHg Process for Stabilizing Mercury
(<260 ppm) Contaminated Mixed Waste. Mixed Waste Focus Area, Innovative Technology Summary
Report, DOE/EM-0468, prepared for Office of Environmental Management, Office of Science and
Technology, September 1999. http://apps.em.doe.gov/ost/itsrtmwfa.html.
DOE 1999f. U.S. Department of Energy. C.H. Mattus. Measurements of Mercury Released from
Amalgams and Sulfide Compounds. ORNL/TM-13728.
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DOE 2001a. U.S. Department of Energy. Guidebook to Decision-Making Methods.
DOE2001b. U.S. Department of Energy. C.H. Mattus. Measurements of Mercury Released from
Solidified/ Stabilized Waste Forms. ORNL/TM-2001-17.
DOE 2002. U.S. Department of Energy. Arrow-PakMacroencapsulation. Mixed Waste Focus Area.
Innovative Technology Summary Report, OST/TMS ID 2159. Prepared for Office of Environmental
Management, Office of Science and Technology.
DPRA Incorporated 1998. Compliance Cost Estimates for the Proposed Land Management Regulation of
Cement Kiln Dust. St. Paul, MN.
ETC 2001. Environmental Technology Council. Incinerator and Landfill Cost Data. May 2001.
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Federal Register 1999. Potential Revisions to the Land Disposal Restrictions Mercury Treatment
Standards (Advanced Notice of Proposed Rulemaking). Volume 64, page 28956. May 28, 1999.
Flexicon 2004. Fax to J. Bubb, MPR Associates, September 14, 2004. FLEXICON Conveyor System for
Granulated Metal Powder.
Fuhrmann, M., D. Melamed, P. Kalb, J. Adams, and L. Milian 2002. Sulfur Polymer Solidification/
Stabilization of Elemental Mercury Waste. Waste Management Journal 22 327-333.
GeoEngineers 2004. Landfill Design and Permitting in Alaska. Available from:
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Global Industrial 2004. Online Catalog. Available at: www.globalindustrial .com.
Gragg, W, LA Chemical 2004. Email to J. Bubb, MPR Associates, September 7, 2004. Cascade.
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Defense National Stockpile Center, Knoxville, TN. September 13, 2001.
Jacobs, N. 2004. Personal communication between Norm Jacobs (NFS) and Geoff Kaiser (SAIC) (and
other EPA/ SAIC/ MPR staff), September 7, 2004.
Jones, N.L, 2003. Notes on Landfill Design. Department of Civil Engineering, Brigham Young
University, CE En 540. Available at: http://class.et.byu.edu/ce540/notes/landfill.pdf
Kalb, P.O. 2001, Brookhaven National Laboratory. Letter to D. Lynch, Defense Logistics Agency, June
28, 2001. Sulfur Polymer Stabilization/Solidification (SPSS) Process for Treatment of Elemental
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Mercury Environmental and Economic Study Final Report April 2005
Mercury, Mercury Contaminated Soils and Debris - Technology Summary: Response to Defense
Logistics Agency Request for Expressions of Interest.
Kalb ,P.D., J.W. Adams, and L.W. Milian 2001. Sulfur Polymer Stabilization/ Solidification (SPSS) of
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Lynch 2002. Letter from D. Lynch, Defense Logistics Agency (Department of Defense), to P. Randall,
U.S. Environmental Protection Agency. June 10, 2002.
Morris, M. and G. Hulet 2003. Development and Selection of Technologies for Mercury Management on
U.S. Department of Energy Sites: The MER01-MER04 and Mercury Speciation Demonstrations. In
WM'03 Conference. February 2003, Tucson, AZ.
Morris, M. et al. 2002. Demonstration of New Technologies Required for Treatment of Mixed Waste
Contaminated with > 260 ppm Mercury.. ORNL/TM-2000/147, Oak Ridge National Laboratory, Oak
Ridge, TN.
MSC Industrial Supply Company 2004. Online Catalog. Available at: www.mscdirect.com.
NEMA2000. Environmental Impact Analysis: Spent Mercury-Containing Lamps. January 2000.
www.nema.org
OMB 2004a. Office of Management and Budget. Discount Rates for Cost-Effectiveness Analysis of
Federal Programs. Federal Register Vol. 69 No. 38 February 26, 2004, pp 8991-8992.
OMB 2004b. Office of Management and Budget. Guidelines and Discount Rates for Benefit-Cost Analysis
of Federal Programs. Circular A-94.
Perma-Fix 2001. Proposal by Perma-Fix for Provision of Elemental Mercury Processing Services. July
6, 2001. Business sensitive information removed.
Perry, R. and D. Green 1997. Perry's Chemical Engineers'Handbook. Seventh Edition.. McGraw-Hill,
New York, NY.
Randall, P., L. Brown , L. Deschaine , J. Dimarzio , G. Kaiser, and J. Vierow, 2004. Application of the
Analytic Hierarchy Process to Compare Alternatives for the Long-Term Management of Surplus
Mercury. Journal of Environmental Management 7j_ (May 2004), 35-43.
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Randall P. 2005. U.S. Environmental Protection Agency. Review of Draft Report Titled "Economic and
Environmental Analysis of Technologies to Treat Mercury and Dispose in a Waste Containment Facility.
Memorandum to Geoffrey D. Kaiser, SAIC, dated January 31, 2005.
Reddy, D.V. and B. Butul 1999. A Comprehensive Literature Review of Liner Failures and Longevity.
Florida Center for Solid and Hazardous Waste Management.
RES (Richardson Engineering Services) 2002. Process Plant Construction Estimating Standards. 2002
Edition^
Safety-Kleen (Lone and Grassy Mountain), Inc. 2001. Module VI, Hazardous Waste Landfills. Grassy
Mountain Facility, State-Issued Part B Permit. April 9, 2001. UTD991301748.
Rocky Mountain Arsenal 2004. On-Post Double-Lined Hazardous Waste Landfills. Available from:
http://www.pmrma.armv.mil/.
SAIC 2002. Science Applications International Corporation. Preliminary Cost Estimate for Long Term
Mercury Storage. Prepared for U.S. EPA Office of Solid Waste through a subcontract with IEC. March
8, 2002.
Salary.com 2004. Salary Wizard. Available at: www.salary.com.
Sanchez, F., D.F. Kosson, C.H. Mattus, and M.I. Morris 2001. Use of a New Leaching Test Framework
for Evaluating Alternative Treatment Processes for Mercury Contaminated Mixed Waste (Hazardous and
Radioactive). Vanderbilt University, Department of Civil and Environmental Engineering. December 14,
2001. Available at http://www.cee.vanderbilt.edu/cee/researchjrojects.html.
SENES 2001. SENES Consultants Ltd. The Development of Retirement and Long Term Storage Options
of Mercury. Prepared for National Office of Pollution Prevention, Environment Canada.
Solis, A., Yale North America 2004. E-mail to J. Bubb, MPR Associates, September 9, 2004. Yale North
America - Lift trucks, fork lifts and hand trucks.
Svensson, Margareta, Bert Allard, and Anders Diiker 2004. On the Choice of Conditions for Geologic
Disposal ofHg-Waste: Formation ofHgS by Mixing HgO or Elemental Hg with S, FeS, or FeS2
(extended abstract). Presented at the 7th International Conference on Mercury as a Global Pollutant,
Ljubljana, Slovenia, June 27-July 2, 2004.
Sweden 2003. Swedish Environmental Protection Agency. A Safe Mercury Repository. A translation of
the official report SOU 2001:58. January 2003.
Ten Siethoff, E., MPR Associates 2004a. Memorandum of August 19, 2004 conference call with EPA,
SAIC, and ADA. ADA/Perma-Fix Sulftde Process.
Ten Siethoff, E., MPR Associates 2004b. Memorandum of September 7, 2004 conference call with EPA,
SAIC, and NFS. Conversation with NFS on the DeHg Process.
Ten Siethoff, E., MPR Associates 2004c. Memorandum of September 8, 2004 Telecon with Youngstown
Barrel & Drum Company Sales Representative. Polyethylene-Lined Steel 55-Gallon Drums.
5-5
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Mercury Environmental and Economic Study Final Report April 2005
Ten Siethoff, E., MPR Associates 2004d. Memorandum of September 30, 2004 Telecon with ERS
Incorporated. HDPE Endcaps.
USAGE 1997. U.S. Army Corps of Engineers. Guidance for Low-Level Radioactive Waste (LLRW) and
Mixed Waste (MW) Treatment and Handling. EM 1110-1-4002.
USDOL 2004. U.S. Department of Labor, Bureau of Labor Statistics. Bureau of Labor Statistics Data.
Available at: www.bls.gov.
USEPA 1998. U.S. Environmental Protection Agency. Municipal Solid Waste Landfills. Compilation of
Air Pollutant Emission Factors AP-42, Section 2.4. November 1998.
USEPA 2000. U.S. Environmental Protection Agency. A Guide to Developing and Documenting Cost
Estimates During the Feasibility Study. EPA 540-R-00-002.
USEPA 2001. U.S. Environmental Protection Agency. Proceedings and Summary Report. Workshop on
Mercury in Products, Processes, Waste and the Environment: Eliminating, Reducing and Managing Risks
from Non-Combustion Sources. March 22-23, 2000. Baltimore. EPA/625/R-00/014. June 2001.
USEPA 2002a. U.S. Environmental Protection Agency. Technical Background Document: Mercury
Wastes. Evaluation of Treatment of Mercury Surrogate Waste. Final Report. February 8, 2002.
USEPA 2002b. U.S. Environmental Protection Agency. Technical Background Document: Mercury
Wastes. Evaluation of Treatment of Bulk Elemental Mercury. Final Report. February 8, 2002.
USEPA 2002c. U.S. Environmental Protection Agency. Preliminary Analysis of Alternatives for the
Long Term Management of Excess Mercury. EPA/600/R-03/048, August 2002. A summary of this
report has been published in the Journal of Environmental Management (Randall et al. 2004).
USEPA 2002d. U.S. Environmental Protection Agency. Advances in Encapsulation Technologies for
the Management of Mercury-Contaminated Waste. Prepared by Chattopadhyay, S. and W. Condit,
Battelle, Columbus, OH.
USEPA 2003. U.S. Environmental Protection Agency. RCRA, Superfund & EPCRA Call Center
Training Module Introduction to Land Disposal Units (40 CFR Parts 264/265, Subparts K,L,M,N).
EPA530-R-04-014.
Utah, 2001. Managing SoilpH in Utah. Utah State University Extension. AG-SO-07.
Utah 2002. Utah Department of Environmental Quality, Division of Solid and Hazardous Wastes.
Information on Commercial and Federal Facilities. http://www.deq.state.ut.us/EQSHW/cffs-l.htm
Wagh, A.S.,D. Singh, and S.Y. Jeong 2000. Mercury Stabilization in Chemically Bonded Phosphate
Ceramics, (author affiliation: Argonne National Laboratory). Presented at the Workshop on Mercury in
Products, Processes, Waste and the Environment: Eliminating, Reducing and Managing Risks from Non-
Combustion Sources. Baltimore, Maryland. Sponsored by U.S. EPA. March 22-23, 2000.
Wong, K.V, G. He, and H. Solo-Gabriele 1997. Infiltration Rates through Synthetic Caps and Side
Slopes at Landfills. January 1997. University of Miami (Florida). Report No. 97-12.
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Zhang, Jian and P.I. Bishop 2003. Stabilization/Solidification of High Mercury Wastes with Reactivated
Carbon. Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management, pp 31-36.
5.2 References Used for Comparative Analyses of Options A-F
Bjasta Atervinning 2001
BNL2001
Bowerman et al. 2003
Bubb 2004b
Butz 2004
Davis and Osucha 1998
DOE 1994, 1999a, 1999f
Fuhrmann et al. 2002
IT/NFS 2001
Jacobs 2004
Kalb2001
Kalbetal. 2001
Lindgren et al. 1996
Morris and Hulet 2003
Perma-Fix2001
Sanchez etal. 2001
Svensson 2004
SENES2001
Ten Siethoff 2004a, 2004b
USEPA 2002a, 2002b, 2002c, 2002d
Zhang and Bishop 2003
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APPENDIX A
DESCRIPTION OF THE
ANALYTIC HIERARCHY PROCESS
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Mercury Environmental and Economic Study Final Report April 2005
Table of Contents
A.I. Analytic Hierarchy Process (AHP) and Expert Choice® A-l
A.2. Expert Choice® in the Environmental Analysis of Technologies to Treat Mercury
and Dispose in a Waste Containment Facility A-2
List of Figures
Figure A-l. Decision Hierarchy A-2
Figure A-2. Full Hierarchical Model A-5
Figure A-3. AHP Goal and Criteria for AHP Analysis A-5
Figure A-4. AHP Alternatives for AHP Analysis A-6
Figure A-5. Results of Pair-wise Comparison of First-Level Criteria A-8
Figure A-6. Priorities of First-Level Criteria Resulting from Pair-wise Comparisons A-8
Figure A-7. Pair-wise Comparison of Second-Level Criteria: During Routine Operations
at Stabilization Facility A-9
Figure A-8. Priorities of Second-Level Criteria Resulting from Pair-wise
Comparisons: During Routine Operations at Stabilization Facility A-9
Figure A-9. Pair-wise Comparison of Second-Level Criteria: During Abnormal or
Accidental Operations A-10
Figure A-10. Priorities of Second-Level Criteria Resulting from Pair-wise
Comparisons:During Abnormal or Accidental Operations A-10
Figure A-ll. Pair-wise Comparison of Second-Level Criteria: During Transportation A-11
Figure A-12. Priorities of Second-Level Criteria Resulting from Pair-wise
Comparisons: During Transportation A-ll
Figure A-13. Pair-wise Comparison of Second-Level Criteria: During Storage in
theMonofill A-12
Figure A-14. Priorities of Second-Level Criteria Resulting from Pair-wise
Comparisons: During Storage in the Monofill A-12
Figure A-15. Assessing Intensities for Low-Moderate-High Scale for Criterion to Minimize
Environmental Impacts from Other Solid Waste Streams A-13
Figure A-16. Priorities for Low-Moderate-High Scale of Criterion to Minimize
Environmental Impacts from Other Solid Waste Streams A-13
Figure A-17. Assessing Intensities for Low-Moderate-High Scale for Criteria to Minimize
Environmental Impacts from Atmospheric Discharges, Elemental Mercury Spills, Other
Spills, and During Decommissioning of the Treatment Unit A-14
Figure A-18. Priorities for Low-Moderate-High Scale of Criteria to Minimize
Environmental Impacts from Atmospheric Discharges, Elemental Mercury Spills, Other
Spills, and During Decommissioning of the Treatment Unit A-14
Figure A-19. Assessing Intensities for Yes-No Scale for Criterion to Minimize Environmental
Impacts During Transportation of Mercury to Stabilization Facility A-15
Figure A-20. Priorities for Yes-No Scale of Criterion to Minimize Environmental
Impacts During Transportation of Mercury to Stabilization Facility A-15
Figure A-21. Assessing Intensities for the Rating Scale for Criterion to Minimize
Environmental Impacts During Transportation of Waste to Monofill A-16
Figure A-22. Priorities for Scale of Criterion to Minimize Environmental Impacts During
Transportation of Waste to Monofill A-16
Figure A-23. Assessing Intensities for the Rating Scale for Criterion to Minimize Environmental
Impacts During Transportation of Reagents A-17
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Mercury Environmental and Economic Study Final Report April 2005
Figure A-24. Priorities for Scale of Criterion to Minimize Environmental Impacts During
Transportation of Reagents A-17
Figure A-25. Assessing Intensities for the Rating Scale for Criterion to Minimize Environmental
Impacts During Storage in Monofill (Expected Ease Maintaining for 40 Years and
Expected Long-Term Susceptibility after 40 Years) A-18
Figure A-26. Priorities for Scale of Criterion to Minimize Environmental Impacts During
Storage in Monofill (Expected Ease Maintaining for 40 Years and Expected Long-Term
Susceptibility after 40 Years) A-18
Figure A-27. Intensity Scoring of Technology Alternatives A-20
Figure A-28. Synthesis of AHP Analysis of Mercury Treatment Technologies Using Expert
Choice® 11 A-21
Figure A-29. Performance Sensitivity Chart for Baseline Conditions A-23
Figure A-30. Dynamic Sensitivity Chart for Baseline Conditions A-24
Figure A-31. Gradient Sensitivity Chart for Baseline Conditions A-24
Figure A-32. Head-to-Head Sensitivity Chart for Baseline Conditions A-25
Figure A-33. Two-Dimensional Sensitivity Chart for Baseline Conditions A-25
Figure A-34. Sensitivity of Changing Final Disposal Criterion from Baseline to 100% A-27
Figure A-35. Sensitivity of Changing Final Disposal Criterion from Baseline to 0% A-27
Figure A-36. Sensitivity of Changing Transportation Criterion from Baseline to 40% A-28
Figure A-37. Sensitivity of Changing Transportation Criterion from Baseline to 10% A-28
Figure A-38. Sensitivity of Changing Abnormal/Accidental Operations Criterion from Baseline
to 40% A-29
Figure A-39. Sensitivity of Changing Abnormal/Accidental Operations Criterion from Baseline
to 10% A-29
Figure A-40. Sensitivity of Changing Routine Operations Criterion from Baseline to 13 % A-3 0
Figure A-41. Sensitivity of Changing Routine Operations Criterion from Baseline to 3.2% A-30
Figure A-42. Sensitivity of Changing Decommissioning Criterion from Baseline to 7.6% A-31
Figure A-43. Sensitivity of Changing Decommissioning Criterion from Baseline to 1.8% A-31
Figure A-44. Uncertainty Analyses A-32
Figure A-45. Synthesized Results from UA 1 A-33
Figure A-46. Synthesized Results from UA 2 A-33
Figure A-47. Synthesized Results from UA 3 A-34
Figure A-48. Synthesized Results from UA 4 A-34
Figure A-49. Synthesized Results from UA 5 A-35
Figure A-50. Synthesized Results from UA 6 A-35
Figure A-51. Synthesized Results from UA 7 A-36
Figure A-52. Synthesized Results from UA 8 A-36
Figure A-53. Synthesized Results from UA 9 A-37
Figure A-54. Synthesized Results from UA 10 A-37
Figure A-55. Synthesized Results from UA 11 A-38
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APPENDIX A
DESCRIPTION OF THE ANALYTIC HIERARCHY PROCESS
A.I. Analytic Hierarchy Process (AHP) and Expert Choice®
The Analytic Hierarchy Process (AHP), developed at the Wharton School of Business by Thomas
Saaty, allows decision makers to model complex problems in hierarchical structures showing the
relationships between the goals, criteria (first- and second-level), and alternatives as shown in Figure A-l.
Uncertainties and other influencing factors can also be included in AHP to model complex problems.
AHP is a mathematically rigorous and proven process that supports informed and independent
decisions involving multiple criteria. AHP provides a formal structure that decomposes complex
problems into sets of smaller, simpler ones. As the smaller problem sets are solved, the reasons for each
choice are weighted and documented to determine the solution of the overall problem.
AHP reduces complex decisions to a series of pair-wise comparisons and then synthesizes the results
to arrive at the best decision based on a structured decision-making process. The implementation of AHP
requires decision makers to choose between first-level criteria, second-level criteria, and alternatives
sequentially at each split in the hierarchy. For example in Figure A-l, which includes 3 first-level
criteria, the first criterion is compared to the second, the second is compared to the third, and the third is
compared to the first. Using this example, assume that decision makers determine that the first criterion
is twice as important as the second (Crit i = 2 * Crit 2), the second is three times as important as the third
(Crit 2 = 3* Crit 3), and the first is six times as important as the third (Crit 1 = 6* Crit 3). In evaluating
the comparison of the first criterion to the third, AHP can be used to confirm the final pair-wise
comparison by using the transitive property of algebra (if Crit i > Crit 2 and Crit 2 > Crit 3, then Crit i >
Crit 3). In this case, the pair-wise comparison and confirmation agree, which would result in a low
"inconsistency index." This index is a measure of the difference between expected and scored
relationships resulting from the pair-wise comparisons. It is a signal to decision makers to reflect on
particular choices that appear to contradict.
Using AHP, the numbers of pair-wise comparisons can become quite large. However, the Expert
Choice® software tool includes a "data grid" or "intensity scale" mode to evaluate alternatives. Pair-wise
comparisons are conducted for the first- and second-level criteria, but intensity scales (e.g., "low,"
"medium," and "high") are used to evaluate each technology alternative individually. Pair-wise
comparisons are conducted for each scale to develop weightings of each scale unit. Intensities then are
derived from (1) ratings, (2), increasing utility curves, (3), decreasing utility curves, (4) step functions, or
(5) direct entries of priorities. Only the "ratings" approach, which uses criterion-specific scales such as
low-medium-high, was used to evaluate intensities for this AHP analysis. The ratings for each criterion
are discussed later in this appendix and in Appendix B.
Additional information about AHP, including an example that illustrates the mathematical foundation
of AHP, is provided in EPA/600/R-03/048, Preliminary Analysis of Alternatives for the Long-Term
Management of Excess Mercury (USEPA 2002c). This appendix focuses on the process for using Expert
Choice® to conduct the environmental analysis of technologies to treat mercury and dispose in a waste
containment facility and the related sensitivity and uncertainty analyses.
A-l
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A.2.
Goal
First-Level Criteria
Second-Level Criteria
rt>
Alternatives •< CK
I
Figure A-l. Decision Hierarchy
Expert Choice® in the Environmental Analysis of Technologies to Treat Mercury and
Dispose in a Waste Containment Facility
To facilitate the pair-wise comparisons and effectively implement the underlying mathematical
framework, Thomas Saaty developed the Expert Choice® software tool. Expert Choice® version 11 was
used to support the environmental analysis of technologies to treat mercury and dispose of the waste in a
containment facility. It was also used to conduct the sensitivity and uncertainty analyses.
The analysis using Expert Choice® includes a seven-step process.
• Step 1: Problem identification and research
• Step 2: Eliminate the infeasible alternatives
• Step 3: Structure a decision model
• Step 4: Evaluate the factors in the model by making pair-wise relative comparisons
• Step 5: Synthesize to identify the "best" alternative.
• Step 6: Examine and verify the decision, iterate as required
• Step 7: Document the decision for justification and control
The first four steps were initiated prior to and completed during a meeting between several experts in
elemental mercury treatment and disposal technologies from the U.S. Environmental Protection Agency
(EPA) and Science Applications International Corporation (SAIC) on 17 and 18 June 2004. The
information gathered during the first four steps was used to complete the fifth and sixth steps. This report
represents completion of the seventh step, which is to document the decision for justification and control.
The following sections describe the steps used to apply AHP and Expert Choice®.
Step 1: Problem Identification and Research
This step includes the following three sub-steps:
• Sub-step la: Identify the problem
• Sub-step Ib: Identify objectives and alternatives
• Sub-step Ic: Research the alternatives.
Sub-Step la: The problem identified for AHP analysis using Expert Choice® was determined at the
conclusion of the Preliminary Analysis of Alternatives for the Long-Term Management of Excess Mercury
(USEPA 2002c) and in EPA's statement of work (SOW) to SAIC. Specifically, it was to conduct the
environmental analysis of technologies to treat mercury and dispose of the waste in a containment facility.
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Mercury Environmental and Economic Study Final Report April 2005
Sub-Step Ib: During the 17 and 18 June 2004 meeting between EPA and SAIC, the choices of the
alternatives listed below were finalized and the following goal was established to focus the AHP analysis:
"Minimize environmental impacts during life cycle." In addition, the following criteria were established
to conduct the AHP analysis using Expert Choice®:
• First-Level Criterion 1: Minimize environmental impacts during routine operation of
stabilization facility
o Second-Level Criterion la: Minimize environmental impacts from solid waste streams
(none of the treatment technologies has liquid waste streams)
o Second-Level Criterion Ib: Minimize environmental impacts from atmospheric
discharges
• First-Level Criterion 2: Minimize environmental impacts during abnormal or accidental
operations
o Second-Level Criterion 2a: Minimize environmental impacts from elemental mercury
spills
o Second-Level Criterion 2b: Minimize environmental impacts from other spills
• First-Level Criterion 3: Minimize environmental impacts during transportation
o Second-Level Criterion 3a: Minimize environmental impacts during transportation of
mercury to stabilization facility
o Second-Level Criterion 3b: Minimize environmental impacts during transportation of
stabilized waste to monofill
o Second-Level Criterion 3c: Minimize environmental impacts during transportation of
reagents
• First-Level Criterion 4: Minimize environmental impacts during decommissioning of the
treatment unit
• First-Level Criterion 5: Minimize environmental impacts during storage in the monofill
o Second-Level Criterion 5a: Expected ease of maintaining environmental conditions (40
years)
o Second-Level Criterion 5b: Expected long-term susceptibility (after 40 years).
The AHP analysis evaluated the following treatment options, macroencapsulation alternatives, and
subsequent alternatives:
• Treatment options:
o Option A process
o Option B process
o Option C process
• Macroencapsulation alternatives:
o Dispose of the treated mercury with macroencapsulation
o Dispose of the treated mercury without macroencapsulation
• Subsequent alternatives:
o Build a fixed treatment facility at one site to which all of the bulk elemental mercury is
transported and dispose of in a collocated monofill (centralized treatment alternative)
o Build one or more portable waste treatment facilities and take them to the sites at which
the bulk elemental mercury is stored and dispose of the treated waste in a centralized
monofill (mobile treatment alternative).
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Mercury Environmental and Economic Study Final Report April 2005
Since the goal of the AHP analysis was to evaluate mercury across the entire treatment and disposal
life-cycle, the alternatives listed above were combined to become the 12 Technology Alternatives
evaluated using Expert Choice® as follows:
1. Option A+no macroencapsulation+centralized treatment
2. Option A+no macroencapsulation+mobile treatment
3. Option A+macroencapsulation+centralized treatment
4. Option A+macroencapsulation+mobile treatment
5. Option B+no macroencapsulation+centralized treatment
6. Option B+no macroencapsulation+mobile treatment
7. Option B+macroencapsulation+centralized treatment
8. Option B+macroencapsulation+mobile treatment
9. Option C+no macroencapsulation+centralized treatment
10. Option C+no macroencapsulation+mobile treatment
11. Option C+macroencapsulation+centralized treatment
12. Option C+macroencapsulation+mobile treatment.
Sub-Step Ic: Research was initiated using the SOW and conclusions from the Preliminary Analysis of
Alternatives for the Long-Term Management of Excess Mercury (USEPA 2002c). Additional research
also was conducted to complete the evaluation of alternatives. Earlier sections of this report discuss the
results of the research.
Step 2: Eliminate the Infeasible Alternatives
This step includes the following two sub-steps:
• Sub-Step 2a: Determine the "musts"
• Sub-Step 2b: Eliminate the alternatives that do not meet the "musts."
Sub-Step 2a: Step 2 was initiated=at the conclusion of the Preliminary Analysis of Alternatives for the
Long-Term Management of Excess Mercury (USEPA 2002c) and in EPA's SOW to SAIC. During the 12
June 2004 meeting between EPA and SAIC, the following "musts" were finalized:
• The alternatives were limited to those specified above (Sub-Step Ib).
• The intent of the AHP was to address environmental effects, not costs. An economic analysis of
the twelve alternatives was performed after completing the AHP analysis.
• Since there are twelve alternatives, the effort required to pair-wise compare these against each
criterion would be excessive (i.e., 12x10 = 120 pair-wise comparisons per objective).
Therefore, the team instead defined a range of "intensities" for each criterion and brainstormed
where each alternative lies within the range.
• The environmental ranking arising from the AHP exercise was not expected to be sensitive to the
total mass of mercury (5,000, 12,000, or 25,000 tons). Therefore, there was no need to specify a
mass for the AHP analysis. [There was some discussion about whether the mass of mercury
might affect some of the criteria (e.g., higher transportation risks for higher quantities), but this
would not influence the rankings because all alternatives would be affected the same way.]
• "No macroencapsulation" meant that the stabilized waste will be placed in the monofill exactly as
it is generated by the stabilization process. If the process ends with the waste solidifying in some
form of container, this container was be given no credit for reducing the rate of leaching.
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Goal
First-Level Criteria
Second-Level Criteria
Alternatives
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Q«
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Figure A-2. Full Hierarchical Model
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Figure A-3. AHP Goal and Criteria for AHP Analysis
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Mercury Environmental and Economic Study
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Goal
First-Level Criteria
Second-Level Criteria
Alternatives ^
Option A, No-MacroEnc
Option A, No-MacroEnc
and Central Treat 4-
and Mobile Treat <-
Option A, MacroEnc, and Central Treat 4-
Option A, MacroEnc, £
Option B, No-MacroEnc
Option B, No-MacroEnc
nd Mobile Treat <-
and Central Treat <-
and Mobile Treat <-
Option B, MacroEnc, and Central Treat <-
Option B, MacroEnc, £
Option C, No-MacroEnc
Option C, No-MacroEnc
Option C, MacroEnc, a
Option C, MacroEnc, £
nd Mobile Treat 4-
and Central Treat <-
and Mobile Treat 4-
nd Central Treat 4-
nd Mobile Treat <-
Figure A-4. AHP Alternatives for AHP Analysis
• "Macroencapsulation in the best available medium" means macroencapsulation in a separate step
after stabilization. It was agreed that, for the purposes of both the AHP and the cost analyses, the
macroencapsulation technology will be the Envirocare ARROW-PAK system, in which waste is
sealed in polyethylene containers prior to disposition in a monofill. The already-formed
polyethylene containers will be purchased from the manufacturers and filled and sealed at the
stabilization site. The ARROW-PAK system is expected to be available in a variety of sizes; the
cost and the environmental analyses incorporated appropriate assumptions for container size.
• Initially, SAIC suggested that the design and construction of the monofill will be independent of
the stabilization technology. However, after some discussion, it was agreed that, while many
elements of the construction will be independent of the disposal alternatives, there might be some
features that are technology dependent, such as the composition of the liner and adjustments to
the fill material.
Sub-Step 2b: After developing the "musts," none of the alternatives were eliminated.
Step 3: Structure a Decision Model
Step 3 includes developing a structured model in the form of a hierarchy to include the goal, criteria
(first- and second-level), and alternatives. This step was completed during the 17 and 18 June 2004
meeting between EPA and SAIC.
Because of the size of the model, it is not practical to enter the information for all of the cells in one
figure. Therefore, Figure A-2 illustrates the structure of the full hierarchical model and Figures A-3 and
A-4 illustrate components of full model in pieces that are more readable.
Step 4: Evaluate the Factors in the Model by Making Pair-wise Relative Comparisons
This step includes the following two sub-steps:
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Mercury Environmental and Economic Study Final Report April 2005
• Sub-Step 4a: Use as much factual data as is available, but interpret the data as it relates to
satisfying the objectives
• Sub-Step 4b: Use knowledge, experience, and intuition for these qualitative aspects of the
problem or when no hard data are available.
Step 4 commenced during the 17 and 18 June 2004 meeting between EPA and SAIC, but because of
the detailed information and the copious time needed to evaluate each alternative relative to each
criterion, Step 4 was completed subsequent to the meeting through a series of electronic mail messages
and telephone conversations. The pair-wise comparisons of the criteria (first- and second-level) were
conducted and finalized during the meeting. Rating scales for the evaluation of intensities for the analysis
of alternatives were discussed conceptually during the meeting, but the actual analysis was conducted
after the meeting.
Sub-Step 4a: During the 17 and 18 June 2004 meeting, pair-wise comparisons were conducted for each
pair of first-level criteria, then for each pair of second-level criteria. SAIC staff facilitated the pair-wise
comparisons by asking questions for each pair such as, "To minimize environmental impacts during the
life cycle of operations, are routine operations of the stabilization facility (First-Level Criterion 1) more or
less important than abnormal or accidental operations (First-Level Criterion 2)?" Similar questions were
asked for each of the remaining pairs of first- and second-level criteria.
In addition, a verbal scale ranging from "equal" to "moderate" to "strong" to "very strong" to
"extreme" was used to evaluate the magnitude of the difference in importance between each pair and
equate to scores of 1, 3, 5, 7, and 9, respectively. Values for 2, 4, 6, and 8 represented scores between the
verbal scale descriptors and non-integer values also could be used, if necessary. The values resulting
from the pair-wise comparisons were positive when the first criterion was deemed more important than
the second and negative when the first criterion was deemed less important than the second. The
following figures illustrate the results of the pair-wise comparisons; values shown in black are positive
and values shown in red are negative. The columns on the left side of each matrix identify the first
criterion and the row-headings across the tops of each matrix identify the second criterion. For example,
Figure A-5 indicates a red "3.0" in the upper left corner of the matrix, which leads to the conclusion that
operations during routine operations at the stabilization facility (criterion to left of matrix) are moderately
less important than operations during abnormal or accidental operations (criterion listed across top of
matrix).
Expert Choice® provides a graphical summary of the priorities of the first-level criteria with respect to
the goal and of the second-level criteria with respect to each first-level criterion. For example, Figure A-5
shows that, during the pair-wise comparisons of the criteria, minimizing environmental impacts during
storage in the monofill is "very strong [ly]" more important than the is minimizing environmental impacts
during routine operations of the stabilization facility. Figures A-5 through A-14 illustrate the results of
the pair-wise comparisons and the priorities interpreted from the comparisons.
Sub-Step 4b: As stated previously, pair-wise comparisons were not performed for the technology
alternatives because of the large number of comparisons that would have been required to evaluate 12
alternatives against 10 criteria. Instead, a set of rating scales or intensities were developed to evaluate
each alternative relative to each criterion.
Qualitative scales were developed for each criterion to measure environmental performance of each
alternative. Pair-wise comparisons like the ones described above were conducted for each scale to
determine the relative priority of each unit of the scale. The following figures illustrate the results and
priorities of pair-wise comparisons of intensity scales for the evaluation of the 12 technology alternatives.
A-7
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File Edit Ass
I tit bi I
'% -t
During routine operation of stabilization facility
Compare the relative importance with respect to: Goal: Minimize environmental impacts during life cycle
During storage in the monofill
if:
- Extreme
- Very Strong
- Strong
- Moderate
- Equal
- Moderate
- Strong
Very Strong
Extreme
Figure A-5. Results of Pair-wise Comparison of First-Level Criteria
C:\ProjectstEPAMER-1UIERCUR~3.AHP
File Edit Assessment View Go lools Help
•e )*. ,... , - , =• | ? ,
Sort bj Name ! Soitbypiioiiij
[ _ Prioni-i'.-; -h'-.b , f^^sect to: !
Goal: Minimize environmental impacts during life cycle
During routine operation of stabilization facility .065
During abnormal or accidental operations .188
During transportation .216
During decommissioning of the treatment unit .038
During storage in the nionofiEl .493
Inconsistency = 0.02
with 0 missing judgments.
Figure A-6. Priorities of First-Level Criteria Resulting from Pair-wise Comparisons
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Mercury Environmental and Economic Study
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C:\Projects\EPAMER~1 \MERCUR- 3.AHP
File Edit Assessment Inconsistency Go Tools Help
Other solid waste streams
Compare the relative importance with respect to: During routine operation of stabilization facility
- Extreme
- Very Strong
- Strong
|- Moderate
- Equal
- Moderate
- Strong
- Very Strong
~ Extreme
Figure A-7. Pair-wise Comparison of Second-Level Criteria:
During Routine Operations at Stabilization Facility
C:\Projects\EPAMER-1WERCUR" 3. AHP
File Edit Assessment View Go lools Help
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Mercury Environmental and Economic Study
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C:lProjecls\EP»MER-1 \MERCUR- 3.AHP
File Edit Assessment Inconsistency Go Tools Help
Elemental mercury spills
Compare the relative importance with respect to: During abnormal or accidental operations
- Extreme
- VerjJ Strong
J- Strong
- Moderate
- Equal
- Moderate
- Strong
- Ver^ Strong
~ Extreme
Figure A-9. Pair-wise Comparison of Second-Level Criteria:
During Abnormal or Accidental Operations
C:\ProjectsVEPAMER-1 \MERCUR- 3.AHP
File Edit Assessment View Go J_ools Help
Sort by Name | Soil by Priorily
LJnsorl V Hcitmajize
ljrinrities with respect to:
Goal: Minimize environmental impacts during life cycle
>During abnormal or accidental operations
Elemental mercury spills .833
Other spills .167
Inconsistency — 0.
with D missing judgments.
Figure A-10. Priorities of Second-Level Criteria Resulting from Pair-wise
Comparisons:During Abnormal or Accidental Operations
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C:\Proiects\EPAMER-1 \MERCLJR- 3.AHP
File Edit Assessment Inconsistency Go Tools Help
- Extreme
Very Strong
Compare the relative importance with respect to: During transportation
Mercury to stabilization facility
Stabilized waste to monofill
Transportation of reagents
Mercury to stabilization Stabilized waste 1 Trans
Figure A-ll. Pair-wise Comparison of Second-Level Criteria:
During Transportation
Si Expert Choice C:\Projects\EPAMER-1\MERCUR-3.AHP
File Edit Assessment View Go J_pols Help
] ^ J j a ".-• A A"
Sort by Name
Sort by Priority |
Unsort
P Normalize
[ Priorities with respect to:
Goal: Minimize environmental impacts during HFe cycle
>During transportation
Mercury to stabilization facility .747
Stabilized waste to monofill .119
Transportation of reagents .134
Inconsistency -0.01
with 0 missing judgments.
Figure A-12. Priorities of Second-Level Criteria Resulting from Pair-wise Comparisons:
During Transportation
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C:\Projecls\EPAMtR-1 UIERCUR- 3.AHP
File Edit Assessment Inconsistency Go Tools Help
l-t- i
Expected ease of maintaining environmental conditions (40 years)
Compare the relative importance with respect to: During storage in the monofill
Expected long-term susceptibility (after 40 years)
Expected ease of mainta Expected Inng-ter
Incon: 0.00
Expected ease of maintaining environmental conditions (40 years]
Expected long-term susceptibility (after 40 years]
Figure A-13. Pair-wise Comparison of Second-Level Criteria:
During Storage in the Monofill
C:\Projects\EPAMER-1\MERCUR-3.AHP
File Edit Assessment View Go lools Help
] 3:1 , w , I- | F | *-f |
Soil by Priority
i LJ |
jJnsorl r Normalize
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C:\Projects\EPAMER-1 \MERCUR- 3.AHP
File Edit Assessment Inconsistency Go Ipols Help
3:1 I UK I —
III, |
Low
7654321234567
Moderate
Compare the relative preterence with respect to: During routine operation of st \ Other solid waste streams
Figure A-15. Assessing Intensities for Low-Moderate-High Scale for Criterion to Minimize
Environmental Impacts from Other Solid Waste Streams
C:\Projects\E PAMER-1 \MERCUR- 3.AHP
File View lools Help
IK,
boal Mii-nrniie enviionrne-ifcl imp ad: d.inng lile ..ML e\Junng ru
r j\ :fa_nli.jd'iun taulitj \_fhe- :olid wa-;te itrearnt.
Sort Assess Clos
Intensity Name
Low
Moderate
High
.265
Figure A-16. Priorities for Low-Moderate-High Scale of Criterion to Minimize Environmental
Impacts from Other Solid Waste Streams
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Si Expert Choice C:\ProjectsVEPAMER-1\MERCUR-3.AHP
File Edit Assessment Inconsistency Go Tools Help
gay al
"• 1 "" 1 -
in, i
Low
98765432123456789
Medium
Compare the relative preference with respect to: During rnutine nperation ot st \ Atmnspheric discharges
Figure A-17. Assessing Intensities for Low-Moderate-High Scale for Criteria to Minimize
Environmental Impacts from Atmospheric Discharges, Elemental Mercury Spills, Other Spills, and
During Decommissioning of the Treatment Unit
C:\Projects\EPAMER-1 \MERCUR- 3.AHP
File Vie» Tools Help
Goal1 Minimize e.nvinjnmerlal impact: duimg lite c',":b\['mng louhne ij|jer.2lio"i nl ilabilcahcn taciliKi ''AhTioi.pheiic discharges
Sort Assess Close
Intensity Name
Low
Priority
1.000
Medium
.550
High
.303
Figure A-18. Priorities for Low-Moderate-High Scale of Criteria to Minimize Environmental
Impacts from Atmospheric Discharges, Elemental Mercury Spills, Other Spills, and During
Decommissioning of the Treatment Unit
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35 Expert Choice C:\ProjectsVEPAMER-1\MERCUR-3.AHP
Hie Edit Assessment Inconsistency Go Tools Help
«• 1"« i -
No
III, |
98765432I234567B9
j
Yes
Compare the relative preference with respect to: Coring transportation \ Mercory to stabilization facility
Figure A-19. Assessing Intensities for Yes-No Scale for Criterion to Minimize Environmental
Impacts During Transportation of Mercury to Stabilization Facility
C:\Projects\EPAMER-1 UIERCUR- 3. AHP
Hie »e« I°°ls Help
in,
Goal: Minimize envnonrnenf.al impact: during lie d'c p'l.'unng tran:pnilahnn \Meiri.in' In itabilization facility
Sort Assess
Figure A-20. Priorities for Yes-No Scale of Criterion to Minimize Environmental
Impacts During Transportation of Mercury to Stabilization Facility
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C:\Proiects\EPAMER-1WERCUR.3.AHP
File Edit Assessment Inconsistency Go Tools Help
311 | » ] =-
III, I
No transport
98765432I23456783
Encapsulated
Compare the relative preference with respect to: During transportation \ Stabilized waste to muiiulill
Figure A-21. Assessing Intensities for the Rating Scale for Criterion to Minimize Environmental
Impacts During Transportation of Waste to Monofill
in,
Goal. Minirnire envinjnrnenfal irnpacl: di.iung lite cv'tleMiuung f[an:purtaliu''i ''..'jtabilized waste to monofill
Sott Assess
Intensity Name
No transport
Encapsulated
Non-encapsulated
Priority
1.000
.225
.127
Figure A-22. Priorities for Scale of Criterion to Minimize Environmental Impacts During
Transportation of Waste to Monofill
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C:\Projects\EPAMER~1 \MERCUR- 3.AHP
File Edit Assessment Inconsistency Go Tools Help
l e
3!l 1 «" 1 -
in, i
Low
Compare the relative preference with respect to: During transportation \Transportation of reagents
- Extreme
- Very Strong
- Strong
J- Moderate
- Equal
- Moderate
- Strong
- Very Strong
- Extreme
Figure A-23. Assessing Intensities for the Rating Scale for Criterion to Minimize Environmental
Impacts During Transportation of Reagents
C:\Projects\EPAMER-1 UIERCUR- 3. AHP
File View lools Help
J iJ A i
.". :l Minnrn:1'' i:"r"1iri:rirrien'al impact: curnc lite :',":le'''Durric I'anip'jrlahjn '< I ra"i:pij[tahijn nf reagents
Sort Assess Close
Intensity Name
Low
Medium
High
Priority
1.000
.405
.164
Figure A-24. Priorities for Scale of Criterion to Minimize Environmental Impacts During
Transportation of Reagents
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C:\Proiects\EPAMER~1WERCUR.3.AHP
File Edit Assessment Inconsistency Go Tools Help
3,1 ,« |=- I
Low
Compare the relative preference with respect to: During storage in the monofill \ Expected ease of maintaining environmental conditions
[40 years)
Moderate
- Extreme
- Very Strong
J- Strong
- Moderate
- Equal
- Moderate
• Strong
- Very Strong
- Extreme
Figure A-25. Assessing Intensities for the Rating Scale for Criterion to Minimize Environmental
Impacts During Storage in Monofill (Expected Ease Maintaining for 40 Years and Expected Long-
Term Susceptibility after 40 Years)
i Expert Choice C:\Projects\EPAMER~1\MERCUR 3.AH1
jle Vie» lools Help_
I DISH
IN,
Goal: Minimize environmental impacts during life cycle\During storage in Ihe nonolill ''.Expected ee:e ut ndintaininq en^'ircnrnenlal cunditujni (40 years)
Sort Assess
Intensity Name
Low
Moderate
High
Figure A-26. Priorities for Scale of Criterion to Minimize Environmental Impacts During Storage
in Monofill (Expected Ease Maintaining for 40 Years and Expected Long-Term Susceptibility after
40 Years)
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Mercury Environmental and Economic Study Final Report April 2005
Although several of the rating scales appear to be the same for different criteria (e.g., 8 of 10 criteria
use a low-medium-high scale), factors and phenomena were applied uniquely for each criterion so the
specific definitions of low, medium, and high were criterion-specific. For example, a low-medium-high
scale was used to evaluate the 12 alternatives with regard to the objective of minimizing environmental
impacts from other solid waste streams. To determine the scores (i.e., low, medium, or high), the wastes
generated during routine operations were evaluated for the following characteristics:
• Non-mercury hazardous waste (assigned 2 points) versus non-hazardous waste (0 points)
• Volumes of waste (mobile alternatives assigned 2 points and stationary assigned 0 points)
• Non-plastic organic wastes (1 point)
• Mercury contents in waste (determine if any technologies deserve an additional point for
generating more mercury-containing waste)
• Powdered (1 point if alternatives include powdered reagents and 0 points if not).
Appendix B describes the "Factors and Phenomena That Need To Be Evaluated When Assigning
Intensities to Alternatives." Following the assessment of intensities and prioritizations of scale units, the
12 technology alternatives were evaluated against the scales. Figure A-27 illustrates the scoring of
intensities for the 12 Technology Alternatives with respect to the lowest-level criteria (1 first-level
criterion and 9 second-level criteria).
Step 5: Synthesize to Identify the "Best" Alternative.
Once judgments are entered for each part of the model, the information was synthesized to achieve an
overall preference. The synthesis ranks the technology alternatives in relation to the goal. Following the
pair-wise comparisons and evaluations of intensities, the actual synthesis of results is executed virtually
instantaneously by Expert Choice®. Figure A-28 illustrates the synthesized results sorted by priority.
In evaluating the synthesis from the perspective of the AHP fundamental principles, the final
inconsistency index shown on Figure A-28 shows that the pair-wise comparisons and confirmations
agree. Generally, when inconsistency indices exceed 0.1, decision makers should consider re-examining
the pair-wise comparisons and intensity assessments because of possible contradictions. However, since
the inconsistency index was well below the recommended value, the pair-wise comparisons and intensity
assessments were not re-examined for this AHP analysis.
Step 6: Examine and Verify the Decision, Iterate As Required
Step 6 includes the following two sub-steps:
• Sub-Step 6a: Examine the solution and perform sensitivity analyses.
• Sub-Step 6b: Check the decision against intuition.
Sub-Step 6a: This step is used to determine if the solution recommended from the AHP analysis is
sensitive to factors in the model for which accurate data are not available, and, if so, considering spending
the resources necessary to collect the necessary data and iterate back to Step 4. Consequently, a "what-if'
sensitivity analysis was conducted following the synthesis of the pair-wise comparisons and intensity
assessments. This analysis did not alter the overall structure of the model, nor did it change any of the
pair-wise comparisons. Instead, several minor changes were made to the assessments of intensities of the
final disposal, transportation, and abnormal/accidental operations criteria.
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K Expert Choice C:\Projects\EPA MercuryUanuary 2005 Fixed DraftUHP AnalysisWercury Model.AHP
File Edit Assessment View Go Plot Tools Formula Type Mapping Totals Help
l=ftls&|
uary 2005 Fixed DraftUHP AnalysisWercury Model.AHP
pe Napping Total? Help
I
Distributive mode
Alternative
^ Option A No-McooEnc, and Central Treat
V' Option A, No-MacroEnc, and Mobile Treat
y Option A MacroEnc, and Central Treat
/ Option A MacroEnc, and Mobile Treat
••Option B, No-MacroEnc, and Central Treat
V. Option B, No-MacroEnc, and Mobile Treat
v. Option B, MacroEnc, and Central Treat
• Option B.. MacroEnc, and Mobile Treat
• Option C, No-MacroEnc, and Central Treat
• Option C Nu-Mac.njEnu and Mobile Trea*
;• Option C, MacroEnc, and Central Treat
V Option C, MacroEnc, and Mobile Treat
<
RATINGS
During routine
operation of st
Other solid
waste streams
(L: .750)
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Low
Moderate
Low
Moderate
RATINGS
During routine
operation of st
Atmospheric
discharges
(L: .250)
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
RATINGS
During
abnormal or
accidental
Elemental
mercury spills
(L: .833)
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
i
RATINGS
During
abnormal or
accidental
Other spills
(L:.1G7)
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
RATINGS
During
transportation
Mercury to
stabilization
facility
(L: .747)
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
RATINGS
During
transportation
Stabilized
waste to
monofill
(L.119)
No transport
Non-encapsulated
No transport
Encapsulated
No transport
Non-encapsulated
No transport
Encapsulated
No transport
Non-encapsulated
No transport
Encapsulated
RATINGS
During
transportation
Tran s p o rtati o n
of reagents
(L.134)
Low
Low
Low
Low
Low
Low
Low
Low
Medium
Medium
Medium
Medium
RATINGS
During
decommission!
ng of the
treatment unit
(L: .038)
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
RATINGS
During storage
in the monofill
Expected ease
of maintaining
environmental
conditions (40
years)
(L: .200)
Moderate
Moderate
Low
Low
Moderate
Moderate
Low
Low
Low
Low
Low
Low
RATINGS
During storage in the monofill
Expected long-term
susceptibility (after 40 years)
(L; 800)
Moderate
Moderate
Low
Low
Low
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
*
-
V,
Figure A-27. Intensity Scoring of Technology Alternatives
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Final Report April 2005
ExpertChoice C:\Projects\EPAMercu ryUan ua r y 200 5 Fixe d D raft\AHP A na lysis\Me r c u ry Mo de I. AHP
File Edit
f*~ Distributive mode
(' Ideal mode
Summary | Details |
Sortby rja
Option A, MacroEnc, and Mobile Treat
Option B, MacroEnc, and Mobile Treat
Option B, No-MacroEnc, and Mobile Treat
Option A, MacroEnc, and Central Treat
Option B, MacroEnc, and Central Treat
Option B, No-MacroEnc, and Central Treat
Option C, No-MacroEnc, and Mobile Treat
Option C, MacroEnc, and Mobile Treat
Option A, No-MacroEnc, and Mobile Treat
Option C, No-MacroEnc, and Central Treat
Option C, MacroEnc, and Central Treat
Option A, No-MacroEnc, and Central Treat
.117
.117
.108
.098
.098
.089
.073
.073
.066
.057
.057
.048
Synthesis with respect to: Goal: Minimize environmental impacts during life cycle
Overall Inconsistency = .02
Figure A-28. Synthesis of AHP Analysis of Mercury Treatment Technologies Using Expert Choice® 11
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Mercury Environmental and Economic Study Final Report April 2005
Expert Choice® 11 includes the following five powerful set of tools for conducting graphically
oriented, interactive sensitivity analyses that enable different views of sensitivity:
• Performance Sensitivity: This chart type displays how each alternative performs with respect to
the goal and each criterion. Additional charts are required to evaluate sensitivities of each
second-level criterion. In Figure A-29, the horizontal colored lines illustrate the relative rankings
or performances of each technology relative to each criterion or the goal (overall). The y-axis
provides the relative priorities and the criteria are listed across the bottom (x-axis). For example,
Figure A-28 shows no difference in performance between technologies when evaluated with
respect to the criteria of minimizing environmental impacts during abnormal conditions and
during decommissioning, which is depicted by the intersection of colored lines. The vertical line
over the work "Overall" indicates the ranking of technology alternatives relative to the goal.
Figure A-29 illustrates the Performance Sensitivity graph for the baseline conditions of the goal.
• Dynamic Sensitivity: As implied by the name, this tool allows users to change the priorities of
the criteria interactively on the chart to determine how the changes affect the priorities of the
technology alternatives. This was the preferred tool for conducting the sensitivity analysis in this
report. Figure A-30 illustrates the Dynamic Sensitivity chart for the baseline conditions. It
shows the relative rankings of the criteria on the left side and the technologies on the right; both
rankings are provided as bar-charts and percentages. As changes are made to the criteria
weightings by sliding the bars right or left reflecting greater or lesser relative importance,
respectively, the impact to the relative ranking of the other criteria on the left side and technology
rankings on the right side change accordingly.
• Gradient Sensitivity: Gradient sensitivity charts illustrate the composite priority of the
technology alternatives with respect to the priority of a single criterion and show "key tradeoffs"
when two or more alternatives intersect each other. Figure A-31 illustrates the priorities of the
technology alternatives (y-axis) with respect to the priorities of the criterion of minimizing
environmental impacts during routine operations of the stabilization facility (x-axis). The vertical
red line represents the default priority of this criterion, which equals 0.065 in this case.
• Head-to-Head Sensitivity: This chart type displays how any two alternatives compare with
respect to the goal and each criterion. Therefore, in addition to the chart for the goal, there could
be as many head-to-head sensitivity charts as there are pairs of criteria. Figure A-32 illustrates
the head-to-head sensitivity between technology alternative 1 (Option A process+no
macroencapsulation+centralized treatment) versus 2 (Option A process+no
macroencapsulation+mobile treatment). Alternative 1 is shown on the left half of the figure and
alternative 2 is shown on the right half. The criteria are listed down the middle of the chart. The
directions of the bars that originate from the middle indicate the technology preferences relative
to the particular criterion. For example in Figure A-32, Alternative 2 is preferred over
Alternative 1 during transportation (red bar) and overall (grey bar) since the bars are pointing
towards Alternative 2. The sizes of the bars represent the relative magnitudes of the preferences.
• Two-Dimensional Sensitivity: These charts are also known as Bubble Plots and display how
alternatives (represented by circles) perform with respect to any of two different criteria. Figure
A-3 3 illustrates how the criterion of minimizing environmental impacts during storage in the
monofill (x-axis) performs relative to the criterion of minimizing environmental impacts during
transportation (y-axis). Two-dimensional plots are divided into four quadrants. Favorable
alternatives appear higher and to the right (i.e., the upper-right quadrant includes most favorable
technology) while less favorable alternatives appear lower and to the left (i.e., the lower-left
quadrant includes the least favorable technologies). Although the technology alternative names
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are truncated on Figure A-33, the most preferred technology (furthest up and to the right) is
Technology Alternative 4 (Option A process+macroencapsulation+mobile treatment) and the
least preferred technologies are either Technology Alternatives 1 (Option A process+no
macroencapsulation+centralized treatment) or 9 (Option C process+no
macroencapsulation+centralized treatment). It is important to note that this type of sensitivity
chart illustrates performance with respect to two particular criteria of concern, so there could be
as many charts as there are head-to-head comparisons.
File Options Window
smwaammfmmaiiSIiiSaailSSiaaasSm
During rnuli During trans
Sensitivity w.r.t.: Goal: Minimize envii on mental impacts during life cycle
Distributive Mode
Figure A-29. Performance Sensitivity Chart for Baseline Conditions
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File Options Window
^N*:| FlE.1 Jlxl
E.5% During muline operation of stabilization facility
uring abnormal or accidental operations
21. G% During transportation
3.8% During decommissioning ol the treatment unit
49.3% During storage in the monotill
0% Option A. No-MacroEnc. and Cential Treat
.6% Option A, No-MacroEnc, and Mobile Treat
M^^^^H
9.8% Option A, MacioEnc, and Central Treat
11.7% Option A. MacroEnc. and Mobile Treat
itial Treat
10.8% Option B. No MacroEnc. and Mobile Treat
|11.7% Option B. MacroEnc. and Mobile Treat
:. and Cential Treat
iption C. No MacroEnc. and Mobile Treat
5.7% Option C. MacioEnc. and Central Treat
7.3% Option C. MacioEnc. and Mobile Tieat
0 1 2 3 4 5 G 7 8 9 ID
Sensitivity w.r.t.: Goal: Minimize envii on mental impacts duiing life cycle
Distributive Mode
Figure A-30. Dynamic Sensitivity Chart for Baseline Conditions
" Facilitator: Gradient Sensitivity for nodes below -- Goal: Minimize environmental impacts during life cycle
File Options XAxis Window
"*N&| ElalJilxl
.4 .5 .6
During ninline opeialion of stabilization facility
Sensitivity wit: Goal: Minimize enviionmental impacts duiing lile cycle
Distiibutive Mode
Figure A-31. Gradient Sensitivity Chart for Baseline Conditions
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Mercury Environmental and Economic Study
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File Options Head_to_head_From Window
QpIionA, No MacroEnc, and Mobile Treat | Option A, MacmEnc. and Central Treat | Dplion A. MacroEnc, and Mobile Treat | Option B. No MacroEnc. and Cential Treat | Opt.L
Option A, No-MacroEnc, and Central Treat -O Option A, No-MacroEnc, and Mobile Treat
During routi
B.83% 5.16£ 3.44% 1.72% 0% 1.72% 3.44% 5.1 B% 6.89£
Weighted head to head between Option A, No-MacroEnc. and Central Treat and Option A. No-MacroEnc, and Mobile Treat
Sensitivity w.r.t.: Goal: Minimize envii on mental impacts during life cycle
[Appendix A.doc - Microsoft Word \
Distributive Mode
Figure A-32. Head-to-Head Sensitivity Chart for Baseline Conditions
File Options XAxis Y Axis Window
During storage in the monolill
O
o
(D
Sensitivity nil: Goal: Minimize environmental impacts duiing life cycl.
During transportation
Distributive Mode
Figure A-33. Two-Dimensional Sensitivity Chart for Baseline Conditions
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Mercury Environmental and Economic Study Final Report April 2005
In conducting the sensitivity analyses, Expert Choice® includes an option to open the Performance,
Dynamic, Gradient, and Head-to-Head charts simultaneously. Changes made to the Performance charts
are reflected in the other charts. This feature was used when conducting the sensitivity analyses for this
project. Figure A-30 above illustrated the Dynamic Sensitivity chart under baseline conditions and can be
used as a point of reference in assessing the differences resulting from the following changes made as a
function of the sensitivity analyses:
• Changing the weight of the final disposal criterion from baseline (49.3%) to 100% (i.e., more
important, Figure A-34)
• Changing the weight of the final disposal criterion from baseline (49.3%)to 0% (i.e., less
important, Figure A-35)
• Changing the weight of the transportation criterion from baseline (21.6%) to 40% (i.e., more
important, Figure A-36)
• Changing the weight of the transportation criterion from baseline (21.6%)to 10% (i.e., less
important, Figure A-37)
• Changing the weight of the abnormal/ accidental operations criterion from baseline (18.8%) to
40% (i.e., more important, Figure A-38)
• Changing the weight of the abnormal/ accidental operations criterion from baseline (18.8%) to
10% (i.e., less important, Figure A-39)
• Changing the weight of the routine operations criterion from 6.5% to 13% (i.e., more important,
Figure A-40)
• Changing the weight of the routine operations criterion from 6.5% to 3.2% (i.e., less important,
Figure A-41)
• Changing the weight of the decommissioning criterion from 3.8% to 7.6% (i.e., more important,
Figure A-42)
• Changing the weight of the decommissioning criterion from 3.8% to 1.8% (i.e., less important,
Figure A-43).
In addition to the sensitivity analyses, eleven sets of uncertainty analyses (UAs) were conducted
to assess the confidence in the results. UAs identify the extent to which variation in the information
and data influences appropriate conclusions. Uncertainty is incorporated into the analysis by using
(1) ranges of available information and data and (2) 'what-if analyses for cases in which the true
range is unknown or not well defined. For example, a different calculation, or assessment, is
generated for values associated with the extreme of a range. Figure A-44 summarizes the 11 UAs by
illustrating the changes that were made to the intensity evaluations. Figures A-45 through A-55
illustrate the synthesized results resulting from the eleven UAs
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Mercury Environmental and Economic Study
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e Options Window
r H=te| FlEl-flxl
0.0% During routine operation of stabilization facility
0_0% During abnormal or accidental operations
n.GZ During transportation
0.0% During decommissioning of the treatment unit
100.0% During storage in the monofill
, 1 , 1 , 1 . 1 . 1 , 1 , 1 . 1 . 1 .
13.1% Option A. MacroEnc. and Mobile Treat
13.1% Option B. MacroEnc. and Mobile Treat
11.4% Option B. No MacroEnc. and Mobile Treat
13.1% Option A, MacroEnc. and Central Treat
13.1% Option B. MacroEnc. and Central Treat
11.4% Option B, No-MacroEnc, and Central Treat
4^%OrJtiori^^acroEnc. and Mobile Treat
4.7% Option C. No-MacroEnc. and Mobile Treat
3J)2M)plion A, No-MacroEnc. and Mobile Treat
4.7% Option C. No-MacroEnc. and Central Treat
4.7% Option C. MacroEnc, and Central Treat
3.0% Option A. No-MacroEnc. and Central Treat
1
) .1
w.i.I.: Goat: Minimize environmental impacts during life c
Figure A-34. Sensitivity of Changing Final Disposal Criterion from Baseline to 100%
12.8% During routine operation of stabilization facility
37.1% During abnormal or accidental operatic
42 B% During transportation
7.5% During decommissioning of the treatment unit
0.0% During storage in the monofill
10.2% Option B, No MacroEnc. and Mobile Treat
oEnc^nd Central Treat
6% Option B. MacioEnc, and Central Treat
6.6% Option B, No-MacroEnc, and Central Treat
39% Option C. MacroEnc. and Mobile Treat
9.8% Option C. No MacroEnc. and Mobile Treat
10.2% Option A. Ho-MacroEnc, and Mobile Treat
G% Option C, No-MacroEnc, and Central Treat
5.6% Option C. MacroEnc. and Central Treat
6.6% Option A. No-MacroEnc. and Central Treat
Figure A-35. Sensitivity of Changing Final Disposal Criterion from Baseline to 0%
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File Options Window
.3% During routine opeiation of stabilization facility
4.4% During abnoimal 01 accidental operations
2_9% During decommissioning ol the lieatmenl unit
37.7% During storage in the monolill
Sensitivity w.r.t.: Goal: Minimize environmental impacts during life cycle
I^XDptionA^acroEnc^ndMobileneat
12.0% Option B, MacroEnc, and Mobile Treat
11.33 Option B. No MacroEnc, and Mobile Treat
8.52 Option B. MacroEnc. and Central Tieal
7.92 Option B. No MacroEnc, and Central Treat
8.5% Option C, MacroEnc. and Mobile Treat
3.42 Option C. No MacroEnc, and Mobile Treat
3.1% Option A. Ho MacroEnc. and Mobile Treat
5.2% Option C. No-MacroEnc. and Central Treat
5.2% Option C. MacioEnc. and Central Tieal
4.72 Option A. No-MacroEnc. and Central Treat
Distributive Mode
Figure A-36. Sensitivity of Changing Transportation Criterion from Baseline to 40%
File Options Window
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File Options Window
jta__x
4.8% During loutine operation of stabilization facility
4IL 12 During abnormal 01 accidental operations
1(U)3U)ptionA^acioEnc^jridMobil^^eat
111 Hx; Option B. MacroEnc. and Mobile Treat
1012 Option B. No MacroEnc. and Mobile Treat
7.6% Option C. No MacroEnc. and Mobile Treat
ri^JloJjacroEnrx and Mobile Treat
6.4% Option C, No MacroEnc, and Central Treat
G.4% Option C, MacroEnc, and Central Treat
5.7% Option A. No-MacroEnc. and Central Treat
.4% Option B. MacioEnc, and Central Treat
8% Option B. Ho-MacroEnc. and Central Treat
Sensitivity w.r.t.: Goal: Minimize environmental impacts during life cycle
Distributive Mode
Figure A-38. Sensitivity of Changing Abnormal/Accidental Operations Criterion from
Baseline to 40%
File Options Window
FIEJ JIxT
r".2% During routine operation ot stabilization Facility
10.1% During abnormal or accidental operations
23.9% During transportation
4.2% During decommissioning ol the treatment unit
54.6% During storage in the monolill
T^^ptionA^acroEnc^n^obM^Treat
12.0% Dplion B. MacroEnc. and Mobile Treat
11.0% Option B, No MacroEnc. and Mobile Treat
72% Option C. No MacroEnc, and Mobile Treat
, and Mobile Treat
5 42 Option C. No-MacroEnc. and Central Treat
4% Option C. MacroEnc. and Central Treat
44% Option A. No-MacroEnc. and Central Treat
Sensitivity w.r.t.: Goal: Minimize environmental impacts during life cycle
Distributive Mode
Figure A-39. Sensitivity of Changing Abnormal/Accidental Operations Criterion from
Baseline to 10%
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File Options Window
13.0% During routine operation of stabilization facility
17.5% During abnormal or accidental operations
20.1% During transportation
3.6% During decommissioning of the treatment unit
45.9% During stoiage in the monofill
^^%OptionA^acroEnc^ndMobileneat
11.4% Option B. MacroEnc. and Mobile Treat
10.6% Option B, No-MacioEnc. and Mobile Treat
9.7% Option A, HacioEnc, and Central Treat
7% Option B. MacroEnc, and Central Treat
9% Option B. No-MacroEnc. and Cential Tieat
T^XOpliori^^acioEnc^nd Mobile Tieat
7.3% Option C, No MacroEnc, and Mobile Treat
No^acroEnc. and Mobile Treat
E.1% Option C. No-MacroEnc. and Cential Treat
B.1% Option C. MacioEnc, and Central Treat
5.0% Option A. No MacroEnc. and Cential Treat
Sensitivity w.r.t.: Goal: Minimize enviionmental impacts duiing life cycle Distributive Mode
Figure A-40. Sensitivity of Changing Routine Operations Criterion from Baseline to 13%
File Options Window
:\<\
I3_2% During mutme opeialmn ol stabilization facility
|19.4% During abnormal or accidental operations
'.2.3% During transportation
^^^^m
4.0% During decommissioning ol the treatment unit
51.OX During storage in the monolill
11.8% Option A. MacroEnc. and Mobile Treat
^^%Optior^^acroEnc^ndMobile^ea^^
10.9% Option B, No MacroEnc, and Mobile Treat
9.9% Option A. HacmEnc. and CenlralTreal
entral Treat
md Cential Treat
iptioriCJ|lacioEnc^and Mobile Tieat
7.3% Option C, No-MacroEnc. and Mobile Treat
[Uj%OptioriA^Jo^acroEnc, and Mobile Treat
5.5% Option C. No MacroEnc. and Cential Treat
5.5% Option C. MacioEnc. and Central Treat
4.7% Option A, No-MacroEnc. and Cential Treat
Distributive Mode
Sensitivity w.r.t.: Goal: Minimize enviionmental impacts duiing life cycle
Figure A-41. Sensitivity of Changing Routine Operations Criterion from Baseline to 3.2%
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• II" ,|>M HLJj^lXI
6.2% During loutine opeiation of stabilization facility
18.1% During abnormal or accidental operations
20.7% During transportation
7.6% During decommissioning of the treatment unit
^^%OptionA^acioEnc^ndMobileneat
11.5% Option B. MacroEnc. and Mobile Treat
10.7% Option B, No-MacioEnc. and Mobile Treat
3.7% Option A, HacioEnc, and Central Treat
7% Option B, MacioEnc, and Central Treat
9% Option B. No-MacroEnc. and Central Treat
7^%Opliori^^acioEnc^nd Mobile Tieal
7.3% Option C, No MacroEnc, and Mobile Treat
7%OptionAJIo^acroEnc, and Mobile Treat
5.8% Option C, No-MacroEnc. and Cential Treat
5.8% Option C, MacioEnc, and Central Treat
4.9% Option A. No MacroEnc. and Central Treat
Sensitivity w.r.t.: Goal: Minimize enviionmental impacts during life cycle Distributive Mode
Figure A-42. Sensitivity of Changing Decommissioning Criterion from Baseline to 7.6%
File Options Window
*\H<\ Fl
^6% During loutine opeiation of stabilization facility
| ID.2% During abnormal 01 accidental operations
g transporlalion
ing decommissioning of Ihe treatment unit
n the monofill
11.7% Option A, HacioEnc, and Mobile Treat
11.7% Option B, MacroEnc, and Mobile Treat
10.8% Option B. No MacroEnc, and Mobile Tieal
9.8% Dplion A. MacroEnc. and Cential Tieat
MacroEnc and Cential Tieat
^^^^^M
ition B, No-MacioEnc, and Central Treat
i ptionCJJacroEnc^nd Mobile Treat
7.3% Option C, No MacroEnc, and Mobile Treat
, and Mobile Treat
5.6% Dplion C, No MacioEnc, and Central Treat
5.6% Option C, MacroEnc, and Cential Tieat
4.7% Option A, No MacioEnc, and Central Treat
Distributive Mode
Sensitivity H.I.I.: Goal: Minimize enviionmental impacts during life cycle
Figure A-43. Sensitivity of Changing Decommissioning Criterion from Baseline to 1.8%
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UA 9: Change from moderate to high
UA 8: Change from moderate to low
UA 3: Change from moderate to low
UA 2: Change from moderate to low
RATINGS
During routine
operation of s
Other solid
waste streams
(L: .750)
RATINGS
During
abnormal or
accidental
Other spills
(L:.1G7)
RATINGS
During
transportation
Mercury to
stabilization
facility
(L: .747}
RATINGS
During
transportation
Stabilized
waste to
monofill
(L.119)
RATINGS 1 RATINGS
ing storage Difing storage in the monofill
te monofill Exnected long-term
ected ease susleptibility (after -10 years)
naintaining (L: (pfi)
iron mental
ditions (10
*rs)
During routine
operation of s
Atmospheric
discharges
(L: 250)
of reagents
(L:.134)
Change both from moderate to low
Change both from low to moderate
No transport Low
to moderate
Chanije from low to moderate
UA 10: Change from moderate to low
UA 11: Change from moderate to high
UA 1: Change all from moderate to low
Figure A-44. Uncertainty Analyses
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V Expert Choice C:\Proiects\EPAMER-1\JANLJAR-1\AHPANA-1\MERCUR-1.AHP
Synthesis with respect to: Goal: Minimize environmental impacts during life cycle
Option A. MacroEnc, and Mobile Treat .101
Option B. MacroEnc, and Mobile Treat .101
Option C. No-MacroEnc. and Mobile Treat 033
Option C. MacroEnc. and Mobile Treat .033
Option B. No-MaoroEnc. and Mobile Treat .092
Option A. MacroEnc. and Central Treat .082 I
Option B. MacroEnc. and Central Treat .032 I
Option C. No-MacroEnc. and Central Treat .082 |
Option C. MacroEnc, and Central Treat .032 I
Option B, No-MacroEnc. and Central Treat .073
Option A, No-MacroEnc, and Mobile Treat .063 |
OptionA.No-MacroEnc.andCentralTreal .044 |
Figure A-45. Synthesized Results from UA 1
C:\Proiects\EPAMER-1UANUAR-1\AHPANA-1\MERCUR-1.AHP
Synlhp:i:
[e:pect to Goal Mir
irnental impacts during life cycle
Overall Inconsistency = .02
Option A, MacroEnc, and Mobile Treat .116
Option B, MacroEnc, and Mobile Treat .116
Option B, No-MacroEnc, and Mobile Treat .108
Option A, MacroEnc, and Central Treat .097
Option B. MacrcEnc, and Central Treat .097
Option B. No-MacroEnc. and Central Treat .039
Option C, No-MacroEnc, and Mobile Treat .072
Option C, MacroEnc, and Mobile Treat .072 |
Option A, No-MacroEnc, and Mobile Treat .066
Option C. No-MacroEnc. and Central Treat .056 |
Option C. MacroEnc, and Central Treat .056
Option A, No-MacroEnc, and Central Treat .055 |
Figure A-46. Synthesized Results from UA 2
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C:\Proiects\EPAMER-1VJANUAR-1\AHPANA-1WERCUR-1 .AHP
File Edit
Al*'l r' E'!l"°utive mode
Ideal mode
Summary | Details |
Synthesis with respect to: Goal: Minimize environmental impacts during life cycle
Overall Inconsistency = 02
Option A. MacraEnc, and Mobile Treat .112
Option B. MacraEnc:, and Mobile Treat .112
Option B. No-MacroEnc. and Mobile Treat .103
Option A. MacroEnc, and Central Treat .093
Option B. MacroEnc, and Central Treat .093
Option A. No-MacroEnc. and Central Treat .084
Option B, No-MacroEnc. and Central Treat .084
Option C, No-MacroEnc, and Mobile Treat .072 |
Option C, MacroEnc, and Mobile Treat .072 |
Option A, No-MacroEnc, and Mobile Treat .065
Option C, No-MacroEnc, and Central Treat .056 |
Option C, MacroEnc, and Central Treat .056 |
Figure A-47. Synthesized Results from UA 3
Expert Choice C:\Project5\EPAMER-1UANUAR-1\AHPANA-1\MERCUR-1.AHP
y^| A" | ff Distributive mode
Summary | Details |
Sort by Mar
Unsort
Synthesis with [expect to" Goal Minimize environmental impact; during life cycle
Overall Inconsistency = .02
Option A. MacroEnc, and Mobile Treat
Option E. MacroEnc, and Mobile Tieat
Option B, No-MacroEnc. and Mobile Treat
Option A, No-MacroEnc, and Central Treat
Option A, MacroEnc, and Central Treat
Option B, MacroEnc, and Central Treat
Option B. No-MacroEnc. and Central Treat
Option C. No-MacroEnc. and Mobile Treat
Option C, MacroEnc, and Mobile Treat
Option A, No-MacroEnc, and Mobile Treat
Option C, No-MacroEnc, and Central Treat
Option C, MacroEnc, and Central Treat
.111
.111
.102
.1392
.092 I
.092 I
.084
.071 |
.071 |
.065 |
.055 |
.055
Figure A-48. Synthesized Results from UA 4
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File Edit
Al*'l r' Distributive mode
Ideal mode
Summary | Details |
Synthesis with respect to: Goal: Minimize environmental impacts during life cycle
Overall Inconsistency = 02
.1 1 8
.099
.099
Option A. MacraEnc, and Mobile Treat
Option B. No-MacroEnc. and Mobile Treat
Option B. MacroEnc, and Mobile Treat
Option A. MacroEnc, and Central Treat
Option B. MacroEnc, and Central Treat
Option B. No-MacroEnc. and Central Treat .090 |
Option C. No-MacroEnc. and Mobile Treat .074
Option C, MacroEnc, and Mobile Treat .074
Option A, No-MacroEnc, and Mobile Treat .066
Option C, No-MacroEnc, and Central Treat .058 |
Option C, MacroEnc, and Central Treat
Option A, No-MacroEnc, and Central Treat
.058 |
.048 |
Figure A-49. Synthesized Results from UA 5
V Expert Choice C:\Proiects\EPAMER-1\JANLJAR-1\AHPANA-1\MERCUR-1.AHP
A[ »' '"' Distributive made <~ Ideal mode I
Summary | Details |
Son by Name | OgEgngritQl _ Unsoit
Synthesis with respect to: Goal: Minimize
jntal impacts during life cycle
Overall Inconsistency = 02
Option A. MacroEnc, and Mobile Treat .123
Option B. No-MacroEnc. and Mobile Treat .114
Option A. MacroEnc. and Central Treat 104
Option B. MacroEnc. and Central Treat .104
Option B. No-MacroEnc. and Central Treat .096
Option 6. MacroEnc. and Mobile Treat .076
Option C. MacroEnc, and Mobile Treat .075
Option C. No-MacroEnc. and Mobile Treat .074
Option A. No-MacroEnc. and Mobile Treat .068
Option C. No-MacroEnc. and Central Treat .058 |
Option C. MacroEnc, and Central Treat .058
OptionA.No-MacroEnc.andCentralTreat .049 |
Figure A-50. Synthesized Results from UA 6
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File Edit
Al*'l r' DislnbuSve mode
Ideal mode
Summary | Details |
Synthesis with respect to: Goal: Minimize environmental impacts during life cycle
Overall Inconsistency = 02
.124
.105
.105
Option A. MacroEnc, and Mobile Treat
Option B. No-MacroEnc. and Mobile Treat
Option A. MacroEnc, and Central Treat
Option B. MacroEnc, and Central Treat
Option B. No-MacroEnc. and Central Treat .096
Option C. MacroEnc, and Mobile Treat .076
Option C. No-MacroEnc. and Mobile Treat .075
Option A, No-MacroEnc, and Mobile Treat .063
Option B, MacroEnc, and Mobile Treat .068
Option C, No-MacroEnc, and Central Treat .059 |
Option C, MacroEnc, and Central Treat .059 |
Option A, No-MacroEnc, and Central Treat .049 |
Figure A-51. Synthesized Results from UA 7
V Expert Choice C:\Projects\EPAMER-1UANUAR-1lAHPANA-1\MERCUR~1 .AHP
-Hl'xl
File Edit
AU'I ? Disliibutiv
Summary | Details
Sort by Name
5 mode (~ Ideal mode
SorlDYPriorlt '|
|
Unsort
j'r'nthe:i:
J
'•lith respect to: Goal: Minimize environmental impacts during lite cycle
Overall Inconsistency = .02
Option B, No-MacroEnc, and Mobile Treat .117
Option A, MacroEnc, and Mobile Treat .116
Option B, MacroEnc, and Mobile Treat .116 |
OptionA, MacroEnc, and Central Treat .097
Option B, MacroEnc, and Central Treat .097
Option B, No-MacroEnc, and Central Treat .089 |
Option C, No-MacroEnc, and Mobile Treat 072
Option C, MacroEnc, and Mobile Treat .072 |
OptionA, No-MacroEnc. and Mobile Treat .065
Option C. No-MacroEnc. and Central Treat .056 |
Option C. MacroEnc, and Central Treat .056 |
Option A, No-MacroEnc, and Central Treat .047
Figure A-52. Synthesized Results from UA 8
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C:\Proiects\EPAMER-1VJANUAR-1\AHPANA-1WERCUR-1 .AHP
File Edit
Al*'l r' E'!l"°utive mode
Ideal mode
Summary | Details |
Synthesis with respect to: Goal: Minimize environmental impacts during life cycle
Overall Inconsistency = 02
Option A. MacraEnc, and Mobile Treat .117
Option B. MacraEnc:, and Mobile Treat .117
Option B. No-MacroEnc. and Mobile Treat .102
Option A. MacroEnc, and Central Treat .093
Option B. MacroEnc, and Central Treat .093
Option B. No-MacroEnc. and Central Treat .090 |
Option C. MacroEnc, and Mobile Treat .074
Option C, No-MacroEnc, and Mobile Treat .073 |
Option A, No-MacroEnc, and Mobile Treat .067 |
Option C, No-MacroEnc, and Central Treat .057 |
Option C, MacroEnc, and Central Treat .057 |
Option A, No-MacroEnc, and Central Treat .048 |
Figure A-53. Synthesized Results from UA 9
Expert Choice C:\Projects\EPAMER-1UANUAR~1XAHPANA-1\MERCUR-1.AHP
j^| fT\
iummary | Derails |
Sort by Name |
Distributive mode
C Ideal mode
':ynH"ip;i: wiHn ie:pecr re _i:d M nrnie envircnTienla impact: during lite cycle
sislency = .02
Option A, MacmEnc, and Mobile Treat .11S
Option B, MacroEnc, and Mobile Treat .11S
Option B, No-MacroEric, and Mobile Treat .107
DptionA, MacroEnc, and Central Treat .037
Option B, MacroEnc, and Central Treat .037
Option B, No-MacroEric, and Central Treat .033
Option C, No-MacroEnc, and Mobile Treat .072
Option C, MacroEnc, and Mobile Treat .072
Option C, MacroEnc, and Central Treat .066
OptionA, No-MacroEric. and Mobile Treat .065
Option C, No-MacroEnc, and Central Treat .056
OptionA, No-MacroEnc, and Central Treat .047
Figure A-54. Synthesized Results from UA 10
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File Edit
Al*'l r' Distributive mode
Ideal mode
Summary | Details |
Synthesis with respect to: Goal: Minimize environmental impacts during life cycle
Overall Inconsistency = 02
Option A. MacroEnc, and Mobile Treat .117
Option B. MacroEnc, and Mobile Treat .117
Option B. No-MacroEnc. and Mobile Treat 10S
Option A. MacroEnc. and Central Treat .093
Option B. MacroEnc. and Central Treat .093
Option B. No-MacroEnc. and Central Treat .090 I
Option C. MacroEnc. and Mobile Treat .074
Option C. No-MacroEnc. and Mobile Treat .073 I
Option A. No-MacroEnc. and Mobile Treat .067 I
Option C. No-MacroEnc. and Central Treat .057 |
Option C. MacroEnc, and Central Treat .051
OptionA.No-MacroEnc.andCentralTreat .048 |
Figure A-55. Synthesized Results from UA 11
Sub-Step 6b: If the results of the synthesis, sensitivity analysis, or uncertainty analysis had not agreed
with intuition, then the AHP process would have been reviewed and, if necessary, modified from any
point between structuring the model through the completion of the uncertainty analysis. However, the
results of the AHP appear to coincide with intuition.
Step 7: Document the Decision for Justification and Control
The conclusion of the AHP analysis suggests that alternatives 4 (Option A
process+macroencapsulation+mobile treatment), 8 (Option B process+macroencapsulation +mobile
treatment), and potentially 6 (Option B process+no macroencapsulation+mobile treatment) are the
technology alternatives most favored by the AHP analysis. These recommendations are based not only on
the AHP analysis, but also interpretation of the information factoring into the AHP analysis.
Consequently, any changes to either the interpretation of the information or the AHP analysis could alter
the recommendations of technology alternatives resulting from the AHP analysis.
Most importantly, the AHP analysis conducted in this appendix was to support informed management
decisions. Consequently, administrative judgment, socio-political factors, or cost not specifically
included in the AHP analysis may factor into the final selection of the preferred technology alternative(s)
and could cause a difference in the recommendation resulting from the AHP analysis.
A-38
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APPENDIX B
FACTORS AND PHENOMENA THAT
NEED TO BE EVALAUTED WHEN
ASSIGNING INTENSITIES TO
ALTERNATIVES
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Mercury Environmental and Economic Study
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Table of Contents
B.I Factors Influencing the Assignment of Intensities to Alternative B-l
B.2 Assignment of Intensities to Alternatives B-3
B.2.1 Recap of Treatment Technologies B-3
B.2.2 Encapsulation B-4
B.2.3 Treatment Location B-4
B.2.4 Disposal B-4
B.2.5 Assignment of Intensities B-4
B.2.5.1 Routine Operation of Stabilization Facility: Solid Waste Discharges B-5
B .2.5.2 Routine Operation of Stabilization Facility: Atmospheric Discharges B-6
B.2.5.3 Abnormal or Accidental Operation of Stabilization Facility: Spills of Elemental
Mercury B-6
B.2.5.4 Abnormal or Accidental Operation of Stabilization Facility: Other Spills B-7
B.2.5.5 Transportation of Mercury to Stabilization Facility B-8
B.2.5.6 Transportation of Stabilized Waste to Monofill B-8
B.2.5.7 Transportation of Reagents B-8
B.2.5.8 Decommissioning of the Stabilization Unit B-ll
B.2.5.9 Monofill Disposal: Expected Ease of Maintaining Environmental
Conditions (within 40 years and following 40 years) B-ll
List of Tables
Table B-l. Reagents Used in Mercury Treatment Technologies B-10
Table B-2. Vapor Pressure Data for Treated Elemental Mercury and Mercury Waste B-12
Table B-3. Assignment of Intensities to Treatment and Disposal Alternatives B-17
List of Figures
Figure B-l. Leaching of Treated Elemental Mercury B-13
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Mercury Environmental and Economic Study Final Report April 2005
APPENDIX B
FACTORS AND PHENOMENA THAT NEED TO BE EVALUATED WHEN
ASSIGNING INTENSITIES TO ALTERNATIVES
B.I Factors Influencing the Assignment of Intensities to Alternative
The following lists contain factors or phenomena that influenced the assigning of intensities to each
elemental mercury treatment and disposal alternative. This list was developed during the EPA/SAIC
AHP brainstorming session on June 17/18, 2004. The team developed a rudimentary scoring system. A
low point score is desirable and corresponds to a low intensity.
The scoring system outlined here was not formally used in the assignment of intensities. However,
the factors discussed for each criterion were an important starting point for research for each alternative.
Goal: Minimize Environmental Impacts During Life cycle
a) During routine operation of stabilization facility (0.065)
• Other solid waste streams (0.750) (everything but atmospheric releases; more concerned with
total waste as opposed to daily totals) - assigned intensity scale: low, medium, high
(pairwise: +2, +3, +3 - see Table 3-1).
a. Non-mercury hazardous waste (2 points) vs. non-hazardous waste (0 points)
b. Volume (Mobile - 2 points; Stationary - 0 points); need to look at each technology
independently to see if they deserve a extra points if they generate considerably more
waste; need to look at larger volumes during scale-up.
c. Includes non-plastic organics (add 1 point).
d. Mercury content in waste (look at each technology comparatively to see if one
technology deserves an additional point for generating more mercury-containing
waste).
e. Powdered (Yes - 1 point; No - 0 points).
• Atmospheric discharges (0.250) - assigned intensity scale low, medium, high (pairwise: +2,
+3, +2)
a. Mercury (not scored because it does not discriminate because each technology would
emit some mercury, but it would be required to meet a regulatory limit, i.e., each
technology would be required to meet the same limit).
b. Ability to control fugitive emissions (process-by-process evaluation).
c. Hydrogen sulfide emissions (1 point if a technology emits H2S; 0 if it does not).
d. Volatile reagents (1 point if a technology emits VOCs; 0 if it does not).
b) During abnormal or accidental operations (0.188)
• Elemental mercury spills (0.833) - assigned intensity scale low, medium, high (pairwise: +2,
+3, +2).
a. Handling of mercury - refers to probability of spill (process-by-process evaluation;
mobile versus fixed; 1 point for a technology if it has additional handling procedures
- this may drop out as a discriminator).
b. Unconventional containers (1 point for mobile treatment because they are more likely
to encounter unconventional containers; 0 points for stationary).
c. Familiarity with procedures (1 point for mobile because they are more likely to have
personnel who are less familiar with process; 0 points for stationary).
1 Values in parentheses are the weights assigned to criteria or subcriteria as a result of the EPA/SAIC team's brainstorming
efforts. See Table 3-1.
B-l
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Mercury Environmental and Economic Study Final Report April 2005
d. Review DLA's Mercury Management Environmental Impact Statement for possible
relevant information.
• Other spills (0.167) - low, medium, high (pairwise: +2, +3, +2).
a. Final waste form (a spill is not going to be a problem due to the stabilized nature of
the final waste form; score = 0 for all technologies).
b. Toxicity of reagents (1 if on a hazardous material list; 0 if it is not).
c. Solid, liquid, or gas? (not likely to have gaseous materials; change to question about
volatility - 1 if volatile, 0 if not).
d. Potential volume (related to inventory, need to make a judgment about what
constitutes a large/small quantity).
c) During transportation (0.216)
• Mercury to stabilization facility (0.747) - assigned intensity scale no, yes (pairwise: +9).
Assignment of intensities by inspection.
• Stabilized waste to monofill (0.119)- assigned intensity scale none, encapsulated, non-
encapsulated (pairwise: +5, +7, +2). Assignment of intensities by inspection.
• Transportation of reagents (0.134) - assigned intensity scale low, medium, high (pairwise:
+3, +5, +3).
a. Volume (process-by-process comparison - which one uses more).
b. Hazards of reagents (1 point for any hazard; 0 for no hazard).
c. Frequency of shipment (redundant - will not be scored, covered by volume).
d. Powdered (Yes - 1 point; No - 0 points).
d) During decommissioning of the treatment unit (0.038) - No subcriteria, assigned intensity scale
low, medium, high (pairwise: +2, +3, +2).
a. Complexity (mobile = 0; fixed = 1).
b. Size (process-by-process comparison).
e) During storage in the monofill (0.493)
• Expected ease of maintaining environmental conditions (40 years) (0.200) - assigned
intensity scale low, medium, high (pairwise: +5, +7, +2).
a. Difficulty in maintaining pH (process-by-process evaluation - need to look at
technologies).
b. Redox potential (process-by-process evaluation - need to look at technologies).
c. Infiltration (not applicable to selecting technologies, but it is location-specific).
d. Liner material durability (0 = available, 1 = unavailable; check to see if liner is
available for technology-dependent conditions).
e. Encapsulated/not-encapsulated (0 = encapsulated; 1 = non-encapsulated).
f Mercury vapor.
• Expected long-term susceptibility to degradation (after 40 years) (0.800) - assigned intensity
scale low, medium, high (pairwise: +5, +7, +2).
a. Leachate rates (favor technologies that are less sensitive to required pH and redox
conditions).
b. Difficulty in maintaining pH (process-by-process evaluation - need to look at
technologies).
c. Redox potential (process-by-process evaluation - need to look at technologies).
d. Infiltration (not applicable to selecting technologies, but it is location-specific).
e. Liner material durability (0 = available, 1 = unavailable; check to see if liner is
available for technology-dependent conditions).
f. Encapsulated/not-encapsulated (0 = encapsulated; 1 = non-encapsulated)
g. Mercury vapor.
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B.2 Assignment of Intensities to Alternatives
This section describes how intensities were assigned to alternatives
B.2.1 Recap of Treatment Technologies
Three technologies (Options A, B, and C) were selected for evaluation. These technologies were
selected for evaluation following a review of potentially applicable treatment methods, see Chapter 2. All
three technologies have been used for the treatment of elemental mercury. Variations of these processes
have also been used for the treatment of mercury-containing wastes such as soils. The references used for
the evaluation of Options A, B, and C are listed in Section 5.2 of the main body of the report.
(a) Option A
Option A is a batch process. In this process, elemental mercury is combined with an excess of
powdered sulfur polymer cement and sulfide additives and heated to 40°C to 70°C for several hours. This
converts mercury to the mercuric sulfide form. Additional sulfur polymer cement is added and heated to
135°C. The molten mixture is poured into a mold to cool and solidify. Pilot scale processing has been
conducted using a one cubic foot vertical cone blender/ dryer with internal mixing and external heating.
Mercury is removed from off-gas using a cyrogenic trap and solid filters. The process has been
demonstrated for both elemental mercury and for mercury-containing soil.
Additives used include the sulfur polymer cement and sulfide additives. Sulfur polymer cement
consists of 95 weight percent elemental sulfur and 5 percent organic binders. Sulfide additives that have
been examined include sodium sulfide monohydrate and triisobutyl phosphine sulfide.
(b; Option B
The Option B technology converts mercury to mercuric sulfide, and is capable of treating elemental
mercury or mercury in waste material. Raw materials for the Option B process include a sulfur-based
reagent. The treated material can be a granular material or a monolithic material. The Option B
amalgamation process, a batch process, consists of combining liquid mercury with a proprietary sulfur
mixture in a pug mill; in one application a 60-liter capacity pug mill was used for treatment of an
elemental mercury waste. Treatment of the liquid mercury was conducted by adding powdered sulfur to
the pug mill, while a preweighed amount of mercury was poured into the mill. As the mill continued to
mix and the reaction took place, additional chemicals were added. While the processing of mercury in the
pug mill was performed without the addition of heat, the reaction of mercury with sulfur is exothermic at
room temperature, and the mixture increases in temperature during processing. Reaction products include
water vapor. Off-gas is passed through a HEPA filter and then passed through a sulfur-impregnated
carbon filter. An EPA elemental mercury study included an additional, laboratory scale
microencapsulation step beyond the pug mill treatment.
(c) Option C
This is a batch mercury amalgamation process conducted at ambient temperature. For elemental
mercury treatment using small quantities of mercury (about 10 kg of treated material per batch), the
treated product is reported to consist of moist amalgam in polyethylene bottles with no free liquid. The
Option C vendor has treated elemental mercury batchwise in the following manner:
1. Elemental mercury is placed in a polyethylene bottle that serves as a reaction vessel. The batch
size is one to two kilograms mercury.
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2. Amalgamation reagents are added and the bottle contents are mixed.
3. Additional chemical stabilization reagents are added, if necessary, if ionic forms of mercury are
suspected of being present.
4. After 24 to 48 hours, the reaction is complete and the final form of the amalgam is a solid mass
within the polyethylene bottle.
B.2.2 Encapsulation
As described above, each of the technologies includes a combination of chemical reaction and
encapsulation to reduce environmental mobility of mercury. For example, the reagents typically provide
both a reaction mechanism and an encapsulation mechanism, not unlike cement-based hazardous waste
stabilization. In addition, containers such as cans or bottles (with drums likely applicable for larger
quantities) are used to hold the treated waste, providing an additional degree of macroencapsulation.
For this evaluation, macroencapsulation consists of a separate step to be conducted following the
treatment step, which is independent of the mercury treatment technology. The evaluation considers a
technology similar to the ARROW-PAK system (DOE 2002). The encapsulation method selected is not
intended to represent the 'best' method, but is expected to display some of the environmental advantages
and cost disadvantages inherent with any macroencapsulation system. For example, molten polyethylene
is alternatively used for macroencapsulation of wastes (DOE 1998a).
In the ARROW-PAK system, polyethylene (HOPE) sleeves are used in conjunction with HDPE
endcaps, which are fused together following insertion of the waste. The ARROW-PAK system is
described as super-compacting waste in 55-gallon drums, placing the compacted drums into 85-gallon
overpacks, and placing the overpacks into the tube (DOE 2002). In its application to treated mercury
waste, the super compaction step may not necessarily be practical given the existing high density of the
treated mercury and the encapsulation already provided by the treatment process. In addition, the
ARROW-PAK system is expected to be available in a variety of sizes; the cost and environmental
analyses will incorporate appropriate assumptions for container size.
B.2.3 Treatment Location
Elemental mercury is first assumed to be stored at a number of existing facilities providing storage or
recovery. Hypothetical examples of such facilities include recovery facilities for fluorescent bulbs or
other mercury-containing equipment; chlor-alkali facilities where mercury is no longer needed due to
process change or closure; and U.S. government storage. Such facilities can be located throughout the
U.S.
For alternatives involving centralized treatment, elemental mercury is transported from these locations
to a single facility where the elemental mercury is treated and disposed. For alternatives involving
mobile treatment, the mercury is treated at these recovery or storage facilities, macro-encapsulated (if
applicable) and then transported to a single disposal site.
B.2.4 Disposal
All alternatives include disposal at a single monofill. The monofill is designed and used solely for the
management of the treated mercury. While the monofill may be constructed at a facility with several
other land disposal units, the intent is that the monofill is located separately from these other units to
allow for better control of the disposal conditions.
B.2.5 Assignment of Intensities
This section describes how intensities were assigned to each alternative for each criterion or
subcriterion.
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B.2.5.1 Routine Operation of Stabilization Facility: Solid Waste Discharges
The mercury treatment operation will typically generate several types of wastes that will require
disposal, discharge, or further offsite treatment. Airborne discharges are discussed in Section B.2.5.2; this
section addresses all other types. Generated wastes include the following:
• Personal protective equipment
• Clean-out wastes
• Empty raw material containers (both elemental mercury and other inputs)
• Air pollution control wastes such as filters
• Waste encapsulant material (for treatment methods employing encapsulation)
The quantities, toxicity, and hazard of these waste materials will affect the overall environmental
impacts. Based on the available information, none of the processes or operations is expected to generate
large quantities of wastes. Following are some aspects to waste generation:
• Non-mercury hazardous waste generation: while all processes generate mercury-containing
hazardous wastes, none of the processes are expected to generate non-mercury hazardous wastes.
All processes will generate empty containers for other reagents; these are not expected to be
hazardous wastes.
• Organic content: none of the processes are expected to generate organic-containing wastes, other
than plastic. The encapsulation step is not expected to significantly affect environmental impacts.
The encapsulating materials are primarily inert plastics and any waste materials are expected to
be easily managed as solids.
• Waste volume: many of the processes generate similar quantities of wastes, such as the following:
o Similar personal protective equipment (e.g., protective clothing and respiratory
equipment) will be required for all management alternatives.
o All processes will generate the same quantities of empty elemental mercury containers
(i.e., flasks).
o Similar air pollution control wastes are expected (e.g., cartridge filters used to remove
mercury) for each of the technology options.
There are some differences between the alternatives, based on the following:
o Mobile equipment will be expected to generate a greater quantity of clean-out wastes in
preparation for movement from site to site.
o Little to no clean-up wastes were identified for the Option C process. Both the Option A
and the Option B processes use mixers/ reactors that will require periodic cleaning.
No specific estimates can be made regarding waste volume beyond these qualitative judgments.
• Wastes in powdered form: each of the technologies use raw material reagents in powdered form
that will generate some waste. Powdered waste forms are expected to be slightly more difficult to
control than other forms.
Based on the above, the centralized Option C process (i.e., Alternatives 9 and 11 - see Section 3.1) is
expected to have low environmental impacts with regard to solid waste discharges due to the low
quantities of clean-up waste expected to be generated. Based on the Option C process description, very
little auxiliary waste is expected to be generated. As with any process, mercury will be present in
personal protective equipment and ambient air filtration/ air treatment devices, while small amounts of
other raw materials may be present in empty reagent bags or drums.
All other alternatives (i.e., Alternatives 1 through 8, 10, and 12) are expected to have moderate
environmental impacts with regard to solid waste discharges, due to the increased quantities of clean-up
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waste expected to be generated. Encapsulation is not expected to significantly affect these environmental
impacts.
B.2.5.2 Routine Operation of Stabilization Facility: Atmospheric Discharges
Mercury treatment will generate atmospheric releases of mercury as well as other pollutants. These
discharges can include the following:
• Mercury: it is assumed that each technology would emit similar (i.e., low) levels of mercury.
USEPA identified that as a result of operating procedures and/or regulatory permits, mercury
emissions at recycling facilities are low (64 Federal Register 28956; May 28, 1999). These
control mechanisms include monitoring and carbon adsorption. For mercury treatment facilities,
whether mobile or centralized, similar precautions are expected to be required with respect to
mercury.
• Fugitive emissions of mercury, there is a potential for fugitive emissions of mercury, such as
during reactor vessel loading/ unloading. In these and other operations, mercury may be more
difficult to control. Based on review of the technologies, none is expected to be more likely to
generate uncontrolled fugitive air emissions than the others.
• Other hazardous pollutants (e.g., hydrogen sulfide, VOCs): none of the processes are expected to
generate or release hydrogen sulfide or VOCs.
• Other pollutants: none of the processes are expected to generate or release other air pollutants
(e.g., sulfur oxides, odor).
Based on the above, all management alternatives (i.e., Alternatives 1 through 12) are expected to
have low environmental impacts with regard to atmospheric discharges during normal operation.
B.2.5.3 Abnormal or Accidental Operation of Stabilization Facility: Spills of Elemental Mercury
There are potential environmental risks to handling elemental mercury. The following are some
accident scenarios that may be applicable for a treatment facility with regard to mercury. If concrete
floors and concrete berms are present at all mercury-handling points (as would be expected in most
cases), the liquid form of mercury is expected to be contained. Therefore, the primary release pathway is
to the air (although other media can be contaminated due to re-settling). These scenarios are adapted
from the DLA Mercury Management EIS (DLA 2004):
• Drop and breakage of a single flask of mercury or a pallet containing multiple flasks (e.g., 30 -
45 flasks).
• A fire occurring at a forklift while holding a pallet of flasks. The contents of the flasks would be
evaporated.
• Building fires and fires in nearby areas (e.g., industrial park).
• Other natural disasters (e.g., earthquake, tornado).
The above four scenarios are ordered from roughly highest to lowest probability (i.e., a single flask
spill is more likely than a tornado). At the same time, the effects from a low probability event such as a
tornado are potentially catastrophic, with the potential for large quantities of mercury to impact the
environment. For the DLA, the catastrophic events were assumed to have a negligible frequency and
were not quantitatively evaluated. Only spills from container breakage were evaluated.
DLA (2004) conservatively estimated that one flask or one pallet would be dropped and broken for
each 1,000 handled. Therefore, a greater amount of handling will result in a greater risk of breakage. The
following handling is expected to be required for a mercury treatment operation:
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• Move elemental mercury from storage location to truck or rail (centralized treatment only)
• Off-load elemental mercury at centralized storage location (centralized treatment only)
• Move elemental mercury from storage area to treatment area within the same facility (both
centralized and mobile treatment)
• Transfer mercury from storage flask to treatment reactor equipment (both centralized and mobile
treatment)
While there is a greater frequency of handling at a centralized treatment location than at a mobile
treatment location, some additional risks of spills may be present at mobile treatment locations:
• Unconventional containers: different types of containers may be present at locations encountered
by a mobile treatment unit. There may be a slight increase in spill risk associated with the
handling of different types of containers.
• Familiarity with procedures: personnel associated with a mobile treatment unit may be less
familiar with the processes than personnel associated with a centralized location.
In addition to these handling concerns, accidents or upsets with the process itself may result in an
accidental discharge of mercury. For example, the air pollution control mechanisms may fail or the
reactor vessels may breach, spilling the contents. The Option A process incorporates elevated
temperatures, where unreacted mercury is much more volatile. Therefore, any equipment failure
associated with the Option A process would result in greater environmental impacts than the other two
processes, in which reactions occur at a more ambient temperature.
Overall, due to the non-negligible risk of spills at both centralized and mobile locations, and the
negligible differences expected among the different technologies, all alternatives (i.e., Alternatives 1 to
12) are expected to present a moderate environmental impact with regard to mercury spills.
B.2.5.4 Abnormal or Accidental Operation of Stabilization Facility: Other Spills
In addition to mercury, there are other materials present at the treatment facility that may be released
to the environment. These include:
• Final waste form: a spill of treated mercury waste at the operating facility is expected to pose no
environmental impacts because the treated materials are solid or monolithic, and spills would be
expected to occur in contained areas as occurs with the elemental mercury. Similarly, further
handling of the final waste form as a result of encapsulation activity will pose negligible risks.
• Treatment reagents: as discussed in Section 2.7, these reagents include the following:
o Inert gases: at least one process (Option A) uses inert gases in its process. Environmental
impacts from these gases are expected to be negligible.
o Sulfur and sulfides: sulfur, sulfur polymer cement, and sodium sulfide are all non-volatile
solids. Their powder form may present a small potential for environmental impact during
a spill. Sodium sulfide presents a greater toxicity than sulfur, although the volume used
is expected to be lower.
o Other proprietary reagents: it is assumed that environmental impacts from spills of other
proprietary reagents are similar to those above.
• Encapsulating material: encapsulating material (e.g., solid plastic) is expected to have negligible
environmental impact.
The mechanisms for release of these materials are similar to that for elemental mercury; namely
container breakage and catastrophic incidents such as fires. Due to the physical form of the materials, the
likely containment mechanisms in place to control solid or liquid releases, and the low volatility of the
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materials to limit airborne releases, the environmental impacts from spills of other (non-elemental
mercury) materials is expected to be low in all instances (i.e., for Alternatives 1 through 12).
B.2.5.5 Transportation of Mercury to Stabilization Facility
In this step, elemental mercury is moved from a central storage/ collection location to a central
treatment location. In cases where the storage and treatment locations are the same, there would be no
risks. This is the case with all mobile treatment alternatives. In all other cases (i.e., centralized
treatment), the precise degree of risk is dependent on the number of trips, facility locations, method of
transport, etc. The risks are not dependent on treatment technology.
There are potential environmental risks to transporting elemental mercury. Elemental mercury is
expected to be transported by truck or rail. The following are several potential risks that may occur
during transportation; these are adapted from the DLA Mercury Management EIS (DLA 2004):
• Accidents resulting in a spill of mercury that will evaporate or otherwise impact the environment.
• Accidents resulting in a fire, and as a consequence some of the mercury will evaporate.
• Accidents resulting in injury or death, generally unrelated to the nature of the cargo. These
effects are outside the scope of the present report because they are not directly related to the
environmental impacts of mercury.
• Risks of the above occurrences are typically assumed to be directly proportional to the number of
miles traveled (e.g., there is twice as much risk with 100 miles of transport than there is with 50
miles of transport).
As a result of this evaluation, all alternatives involving mobile treatment are assigned an intensity of
'no' (i.e., Alternatives 2, 4, 6, 8, 10, 12). The remaining six alternatives would be assigned an intensity
of'yes.'
B.2.5.6 Transportation of Stabilized Waste to Monofill
This step involves the movement of treated mercury waste from a central treatment location to the
disposal site. In cases where the treatment and disposal locations are the same, there would be no risks.
This is the case with all centralized treatment alternatives. In all other cases (i.e., mobile treatment),
risks are expected to result from similar scenarios as discussed above in Section B.2.5.5. However, risks
from treated wastes are expected to be much smaller than risks from elemental mercury. Further, risks
are expected to be slightly lower for encapsulated waste than for non-encapsulated waste. In the event of
an accident, the encapsulation material will help prevent the containerized waste from being released to
the environment.
As a result of this evaluation, all alternatives involving central treatment are assigned an intensity of
'no transport' (i.e., Alternatives 1, 3, 5, 7, 9, 11). The three remaining alternatives involving
encapsulation would be assigned an intensity of 'encapsulated' (i.e., Alternatives 4, 8, 12). The three
remaining alternatives not involving encapsulation would be assigned an intensity of 'not encapsulated'
(i.e., Alternatives 2, 6, 10).
B.2.5.7 Transportation of Reagents
Various raw materials are required to treat the mercury, regardless of the treatment location. These
materials include treatment reagents such as sulfur. Factors potentially affecting environmental impacts
from transportation include the following:
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• Volume of reagents required (e.g., per pound of mercury treated): these affect the number of
vehicle-miles and the subsequent probability of a release.
• Hazards of reagents: toxicity, reactivity, and flammability.
• Physical state of reagents: powdered or volatile reagents are expected to be more difficult to
clean up (or more likely to impact the environment) than other forms.
In addition to reagents, encapsulation material (e.g., the polypropylene container) will also require
transport to the treatment site. The shipment of encapsulation material is unlikely to have environmental
impacts similar to the above, because the encapsulation material is a solid mass of low hazard. Shipments
will affect the generation of pollutants such as greenhouse gas from truck exhaust; such environmental
impacts are outside the scope of this present analysis.
Risks from transportation of reagents are expected to differ based only on the three technology types.
For example, risks are assumed to be independent of whether an additional encapsulation step is
performed, and whether treatment is conducted at a mobile location or a centralized location.
Table B-l summarizes the hazards posed by the reagents identified as raw materials in each of the
technologies. For comparison, the hazards associated with mercury are also listed. Unfortunately, several
reagents are identified as proprietary and in these cases no evaluation can be conducted.
(a) Option A
The following reagents are used in Option A for treating elemental mercury:
• Sulfur polymer cement, ground to a fine powder of approximately 60 mesh (0.25 mm). Sulfur
polymer cement is a product formed from the reaction of 95 percent sulfur and five percent
organic modifier. The organic modifier is an oligomer/ polymer.
• A sulfide additive such as sodium sulfide (Na2S), also in powder form.
• Argon gas or nitrogen gas is used to maintain an inert atmosphere (e.g., absent of oxygen) during
the reaction.
Argon and nitrogen gases are non-reactive and non-flammable; their principal hazards are those
associated with any compressed gas (i.e., rapid decompression). The process uses relatively high
quantities of sulfur polymer cement and lesser quantities of sulfide additive. There is a 2:1 weight ratio of
added reagents to elemental mercury; three percent is sulfide additive. As shown in Table B-l, the
hazards of SPC are much lower than the hazards of sodium sulfide. Therefore, although both reagents are
present in powdered form (which may increase potential releases or hazard), the overall environmental
impacts for reagent transport associated with this technology (i.e., Alternatives 1-4) are expected to be
low.
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Table B-l. Reagents Used in Mercury Treatment Technologies
Chemical
Mercury
Sulfur polymer
cement (powdered)
Calcium
polysulfide
Sodium sulfide
(powdered)
Argon or nitrogen
gas
Proprietary
(assume powder
form)
Proprietary
Technology
Options A and
B
Option B
Option A
Option A
Option C
Option B,
Option C
Hazards
Extreme health hazard
(poison) via inhalation, no
flammable hazard, slight
reactivity hazard
Slight health, flammability,
and reactivity hazards
Corrosive and ingestion
health hazards
Severe health (corrosive) to
mucous membranes; slight
flammability and reactivity
hazards
None with gas; some
decompression hazards
with pressurized container
Hazards are unknown;
powder forms present
greater hazards
Unknown
Notes
For reference/ comparison
Based on MSDS for powdered
sulfur. Hazards for powdered SPC
are expected to be similar or lower.
Based on MSDS
Based on MSDS
(b) Option B
The following reagents are used for treating elemental mercury in Option B:
• Powdered sulfur.
• Calcium polysulfide.
• Smaller quantities of additional proprietary reagents.
The principal reagent is expected to be the powdered sulfur. The overall quantities of reagents used
are approximately 1:1 (weight percent of reagents to mercury). The environmental impacts of reagent
transport associated with this technology (i.e., Alternatives 5-8) are expected to be similar to those for
Option A, and are therefore low.
(c) Option C
Available information regarding the reagents used during treatment of elemental mercury is
proprietary. Initial treatment is known to be an amalgamation that satisfies the requirements of 40 CFR
268.42 (i.e., "utilizes inorganic reagents such as copper, zinc, nickel, gold, and sulfur"). Based on the fact
that the other two technologies employ powdered reagents, it is assumed that the Option C process also
employs powdered reagents. Powdered reagents have greater surface area and will react more readily
with the mercury.
Due to the proprietary nature of the process reagents, it is difficult to identify hazards. Option C uses
larger quantities of reagents than the other processes; the ratio of reagents to mercury is approximately
5.6:1 versus slightly lower ratios for the other processes. Due to the larger quantities of reagents used,
and the uncertainties regarding their hazard, the environmental impacts associated with this technology
(i.e., Alternatives 9-12) are expected to be moderate.
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B.2.5.8 Decommissioning of the Stabilization Unit
A one-time, permanent dismantling of the treatment unit will be conducted. If the stabilization unit is
mobile, the unit will require periodic cleaning and dismantling as it moves from one location to another.
Such operations are considered within the range of normal activities evaluated in Sections B.2.5.1 and
B.2.5.2.
Permanent decommissioning is expected to involve the following activities:
• Removal or disposal of excess reagents.
• Decontaminating all process equipment and subsequent disposal or scrapping of equipment
• Decontaminating floors, building surfaces, etc.
• Disposal/ processing of mercury-containing wastes generated from these decommissioning
operations.
These activities are not expected to differ significantly by technology or mobility (i.e., centralized
versus mobile). Small differences in complexity with regard to these factors are not expected to
significantly impact the quantities or composition of the generated wastes. Therefore, the environmental
impacts are expected to be low in all instances (i.e., for Alternatives 1 through 12).
B.2.5.9 Monofill Disposal: Expected Ease of Maintaining Environmental Conditions (within 40
years and following 40 years)
In evaluating environmental impacts, two criteria were identified with respect to monofill disposal:
(1) the expected ease of maintaining environmental conditions within 40 years, and (2) expected long-
term susceptibility to degradation following 40 years. A 40-year time frame was selected for consistency
with alternatives evaluated for the DLA; it is also a time period in which many short-term fluctuations of
a disposal environment have been completed.
Many of the factors influencing environmental impact are similar regardless of whether the period of
time reviewed is less than or greater than 40 years.
In minimizing environmental impacts of mercury from disposal, it is important to minimize both the
leaching and the volatilization of mercury from the waste. This is accomplished through a combination of
using treatment techniques that best immobilize the mercury, and selecting and maintaining an
environment in which the waste is best immobilized. These factors are discussed below.
(a) Volatilization
Data for mercury vapor releases from treated elemental mercury are available from prior DOE
studies. Data are available for each of the three processes evaluated for this report. These data do not
represent long-term stability results and therefore insufficient data are available to identify either the
significance of this pathway (relative to leaching) or environmental conditions in which volatilization is
minimized. Nevertheless, the data are useful in identifying differences in results between the processes
and suggesting how vapor releases can be minimized.
There are two concerns with volatilization. First, this represents a release pathway into the
environment. Second, it presents a potential problem with macroencapsulation. Macroencapsulation
techniques such as the Arrow-pak system result in a sealed container; the generation of gas within such a
container may result in increased pressures leading to structural deformation (DOE 2002).
Data are available for elemental mercury, treated elemental mercury, and treated mercury wastes.
Data are available specifically for the three vendors evaluated in this report, as well as for similar
technologies. For ease of presentation, only data for elemental mercury and elemental mercury treated by
the three technologies evaluated in this report are presented.
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A recently published study presents data for one of the Vendors evaluated in this report, identifying
the mercury vapor concentration over treated elemental mercury as a function of time. The data only
identify results for a seven-day period following generation. The results show that the concentration
decreases over time following initial treatment, although the timeframe is too short to identify long-term
trends. Nevertheless, the results suggest that emissions of mercury can occur immediately following
treatment. During this period, the treated mercury can be allowed to set in an area with controlled
ventilation prior to macroencapsulation (if applicable) and final disposal. However, no further
conclusions regarding mercury volatility, such as in the disposal environment, can be made from the
available data.
DOE has evaluated short-term mercury vapor concentrations for elemental mercury treated by two of
the vendors evaluated in this report. Results for one of the Vendors showed very little volatilized
mercury. However, the samples treated by another Vendor displayed very high mercury vapor levels,
comparable to untreated elemental mercury. Correspondence with one of the vendors has suggested
uncertainties with the DOE data.
The available volatilization data are presented in Table B-2.
Table B-2. Vapor Pressure Data for Treated Elemental Mercury and Mercury Waste
Waste Type
Elemental Hg
Elemental Hg
Elemental Hg
Elemental Hg
Technology
Untreated -
Calculated
Vendor A
Vendor B
Vendor C
Hg (mg/m3)
Iday
14
11
Not detected *
10.04-10.21
**
3 day
14
3.8
Not detected *
10.22-10.40
**
7 day
14
1
Not detected *
9.95-11.78
**
Reference
DOE 1994; DOE
1999f
See Section 5. 2
See Section 5. 2
See Section 5. 2
Notes: Data are for ambient conditions (~20C)
* Limit of sensitivity is approximately 0.003 mg/m3.
** Results present averages of two separate batch tests after 2 day, 5 day, and 14 day.
Based on the results in Table B-2, the Vendor C process may generate significant quantities of
mercury vapor, such that any further macroencapsulation may be compromised, and which result in a
potential environmental impact pathway. Uncertainties with these results include whether or not such
volatilization would continue for an intermediate to long period of time (e.g., whether volatilization rate
would decrease). There is further uncertainty regarding the validity of the DOE results.
(b) Favorable pH Conditions and Expected Ease of Maintenance
The pH of the monofill is an important parameter in determining mercury leaching from treated
elemental mercury. The monofill pH will be determined by the pH of the materials being disposed (e.g.,
both the waste and the fill material), precipitation/ run-on, and chemical or biological changes within the
disposal cell. The solubilities of the chemical species within the treated waste (which result in the degree
of mercury leaching) are a function of pH.
Each of the treatment technologies generate treated wastes with different pH; they each appear to
perform best under different pH conditions. Results of USEPA (2002b) testing of treated elemental
mercury show the following:
• Treated mercury waste from the Option A process has a pH of approximately 11; leaching
solutions with acidic pH generally result in decreased leaching for this treatment process.
• Treated mercury waste from the Option B process has a pH of approximately 7-8; leaching
solutions with acidic pH generally result in decreased leaching for this treatment process.
B-12
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Mercury Environmental and Economic Study
Final Report April 2005
• Treated mercury waste from the Option C process has a pH of approximately 10; leaching
solutions with basic pH generally result in decreased leaching for this treatment process.
The results from the EPA elemental mercury study are shown in Figure B-l.
Therefore, these results show that it is desirable to maintain pH conditions within the landfill at acidic
conditions for the Option A and B processes, while the Option C process favors basic conditions.
The pH of the soil/ fill material will also influence the conditions within the disposal unit. Soil pH
varies as a function of geography; low rainfall environments (which are favorable locations because they
result in low landfill infiltration) tend to have basic pH. The pH range for most U.S. soils is from 4 to 10
(Utah 2001). The pH of soils can be increased by adding lime, and decreased by adding sulfuric acid.
Changing the soil pH can be difficult, for example because in basic soils lime acts as a buffer (Utah
2001).
Many commercial hazardous waste landfills used for the disposal of inorganic wastes have leachate
with basic pH. Metal-containing wastes are often stabilized using cement, which favors basic conditions
within a landfill. Therefore, it is expected to be somewhat easier to maintain a basic environment because
there is sufficient experience in operating disposal units in these conditions. The pH can be adjusted, for
example, through the incorporation of lime or cement to the fill material.
From the above information, the combined contributions from the waste and soil tend to result in
basic conditions, however basic conditions favor only the Option C process. The Option A and B
processes favor acidic conditions that are expected to be more difficult to maintain.
10000
1000
100
10
0.01
0.001
—•— Vendor A Pellets
~~O— Vendor A Crushed
—X— Vendor B
Vendor C
pH
Source: Data from EPA (2002b).
Figure B-l. Leaching of Treated Elemental Mercury
B-13
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Mercury Environmental and Economic Study Final Report April 2005
(c) Long-Term Stability of the Waste Forms
Testing to identify changes over time is useful in assessing the affect of disposal conditions on the
treated mercury. Two studies have been identified that provide some insight with regard to how disposal
conditions would influence the treated wastes.
In work conducted by DOE, elemental mercury was treated by the Option B and Option C processes
and was exposed to solutions with an initial pH ranging from 3 to 12.5, over a period of time ranging
from two weeks to three months. Observations from these experiments show that acidic solutions have a
deleterious effect on the Option C waste form, whereas the basic solutions are more aggressive towards
the Option B waste form. This is consistent with work carried out by EPA. No conclusions were drawn
relating to the trends in mercury leaching over time.
Data available regarding the formation of mercuric sulfide under long-term conditions are available
from Svensson et al. (2004); these data are not specific to any particular technology but can potentially be
useful for sulfur-based treatment processes in general. These experiments included the mixing of
elemental mercury and sulfur and evaluating the effects under various conditions over a two-year period.
The highest rate of formation of mercuric sulfide occurred under anaerobic conditions and high pH.
These data have limited application because they relate to the formation of mercuric sulfide rather than its
degradation. Nevertheless, conditions that favor mercuric sulfide are favorable because unreacted
mercury will likely be present in any disposed waste.
(d) Long-Term Stability of the Encapsulating Material
In alternatives where the treated mercury is macro-encapsulated prior to disposal, it is desirable for
the encapsulating material to last as long as possible. Overtime, the material may develop cracks, etc.,
which result in degraded environmental performance.
ARROW-PAK consists of high-density polyethylene (HOPE) Phillips Marlex® resin, approximately
one inch thick (Harrell and Hotard 1995; DOE 2002). The resin is formed into hollow tubes (where
drums of waste are placed) and endcaps for the tubes; the caps are subsequently fused to the tubes to
provide a seal. The developers conservatively estimate a life expectancy of 100 years minimum (Harrell
and Hotard 1995) and DOE estimates an outdoor storage life in the range of 100 to 300 years (DOE
1998b). The material is identified as inert with respect to most temperatures, chemicals, biological
organisms, and ultraviolet light conditions likely to be encountered in a disposal environment (Harrell and
Hotard 1995).
The properties of polyethylene (such as HOPE) have been shown to be unaffected when exposed to
solutions with low or high pH (pH 3 and 12). HOPE is affected by some organic chemicals including
halogenated hydrocarbons: however such organic chemicals are not expected in the monofill environment
(Reddy and Butul 1999).
(e) Other Conditions Affecting Disposal
Redox potential (e.g., the presence or absence of aerobic conditions) is a potentially important
property affecting stability or leaching. For example, mercuric sulfide formation is favored (or proceeds
faster) in alkaline anaerobic conditions. Virtually all leaching data are available for aerobic conditions.
Therefore, it is difficult to incorporate data regarding redox potential into the analysis.
(f) Conclusions Regarding Criterion: Expected Ease of Maintaining Environmental Conditions for up
to 40 Year?,
B-14
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Mercury Environmental and Economic Study Final Report April 2005
For this criterion, the following aspects discussed above are expected to be relevant:
• Maintaining landfill pH at favorable conditions
• Stability of the encapsulating material
As discussed above, encapsulation material is expected to provide protection of the waste from the
landfill environment for at least 100 years. In addition, wastes from the Option C process favor basic
environments that are expected to be easier to maintain. Therefore, for this criterion, processes relating to
macroencapsulation alternatives or the Option C process (i.e., Alternatives 3, 4, 7 through 12) are
assigned a value of low impacts, while the remaining alternatives (i.e., Alternatives 1, 2, 5, 6) are
assigned a value of moderate impact.
(g) Conclusions Regarding Criterion: Expected Long-Term Susceptibility to Degradation after 40
Years
This criterion incorporates the two aspects discussed in (f) immediately above plus several others, as
follows:
• Maintaining landfill pH at favorable conditions
• Stability of the encapsulating material
• Volatility and/ or leaching rates
As discussed above, the volatility rate of the Option C-treated waste appears to be significantly
greater than for the remaining two processes. This also affects the integrity of any encapsulation
technology, as gas build-up is expected to shorten the life of an encapsulating material.
Based on the EPA data, leaching rates for wastes from the Option B process have less variation with
respect to pH than the other technologies. While leaching rate is favored at low pH (as with the Option A
process), there is significantly less variation in results as the pH moves away from this 'optimum' value.
Therefore, the importance of maintaining critical pH monofill conditions is less for the Option B process
than for the other processes.
Each of the alternatives has various advantages and disadvantages which makes it difficult to assign
intensities. Macroencapsulation will typically always have an environmental advantage over no
encapsulation, but after a period of time it is appropriate to assume degradation of the containers, at which
point the advantages of macroencapsulation are lower (similar to assumptions that can be made
concerning the long-term behavior of landfill liners). Wastes from the Option C process will likely
exhibit low leaching at elevated pH, but the high rate of volatility (based on available data) will result in
increased environmental impacts from this pathway as well as potential shortened life of the
macroencapsulation material. Wastes from the Option B process, while less sensitive to pH variation than
other processes, favor low pH environments that may require monitoring and adjustment.
Other uncertainties are associated with long-term stability of the disposal site. Over time, the landfill
cap, liner materials, and leachate collection systems may erode or cease functioning, resulting in
increased infiltration and leachate generation. Such an effect would be negative for any evaluated
alternative, but would not be expected to adversely affect one alternative more so than another. Another
potential negative effect could result in the landfill environment deviating from 'favorable' conditions.
For example, as shown in Figure B-l, pH has a significant effect on leachate mercury concentration.
However, in a hypothetical long-term scenario, a favorable environment may not be assured and pH may
raise or lower overtime to 'less favorable' conditions. For this reason, as discussed above, the low
variation in Option B (relative to Options A and C) would be expected to mitigate such potential failure
B-15
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Mercury Environmental and Economic Study Final Report April 2005
With significant uncertainty and variability, processes relating to Option A macroencapsulation
alternatives orthe Option B process (i.e., Alternatives 3 through 8) are assigned a value of low impacts,
while the remaining alternatives (i.e., Alternatives 1, 2, 9 through 12) are assigned a value of moderate
impact.
(h) Summary of Assignment of Intensities
Table B-3 contains a summary of the intensities that were assigned in the foregoing.
B-16
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Mercury Environmental and Economic Study
Final Report April 2005
Table B-3. Assignment of Intensities to Treatment and Disposal Alternatives
Treatment and
Disposal Alternative
Option A+ NMEa +
CTAC
Option A+ NMEb
+MTAd
Option A+ ME + CTA
Option A+ ME + MTA
Option B+ NME + CTA
Option B+ NME + MTA
Option B+ ME + CTA
Option B+ ME + MTA
Option C+ NME + CTA
Option C+ NME + MTA
Option C+ ME + CTA
Option C+ ME + MTA
Routine Operations
Solid
Waste
Discharges
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Low
Moderate
Low
Moderate
Atmospheric
Discharges
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Accidental
Releases
Mercury
Spills
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Moderate
Other
Spills
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Transportation
Mercury
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Yes
No
Waste
No
NME
No
ME
No
NME
No
ME
No
NME
No
ME
Reagents
Low
Low
Low
Low
Low
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
Decom-
missioning
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Low
Monofill Storage
<40
years
Moderate
Moderate
Low
Low
Moderate
Moderate
Low
Low
Low
Low
Low
Low
>40
years
Moderate
Moderate
Low
Low
Low
Low
Low
Low
Moderate
Moderate
Moderate
Moderate
a. NME = Not Macroencapsulated. b. ME =
b. CTA = Centralized Treatment Alternative.
Macroencapsulated
MTA = Mobile Treatment Alternative
B-17
-------
-------
Appendix C
Option A Process
Input Information for Cost Estimates
This appendix provides input that was used to estimate the capital and O&M costs for the Option A treatment process,
together with the macroencapsulation process. Any costs quoted in this appendix are point estimates.
They were subsequently assigned uncertainty distributions as described in Section 4.5
and run through a Crystal Ball Monte Carlo analysis.
Appendix C-Option A costs_Final.xls C-1
-------
Treatment Proc Dia
PROCESS CAPACITY
Mercury processed per batch
Batches per mixer-shift
Number of mixers
Workweek
Shifts per day
Work year
Utilization
Equipment work year
525 kg
1
5
5 days
2
520 shifts/year
80%
416 shifts/year
Annual mercury processing capacity 1,092 tons/year
Required mercury processing throughput: 1,000 tons/year
MERCURY, REAGENT, AND WASTE RATIOS
In each batch mixture, % (by mass) of:
Mercury: 33%
Sodium sulfide: 2%
Sulfur Polymer Cement: 65%
Name: Crane
Cost category: Capital cost
Cost: $78,000
Quantity: 1
Total cost: $78,000
Mercury j
flask
Mercury processed per batch:
Sodium sulfide per batch:
Sulfur Polymer Cement per batch:
Total batch mass:
REAGENT CONSUMPTION
Mass of mecury processed in one batch:
Mass of mercury processed per year:
525 kg
31.8 kg
1034 kg
1591 kg
525 kg
1,000 tons/year
1,000,000 kg/year
Name: SPC feeder
Cost category: Capital cost
Cost: $44,100
Quantity: 5
Total cost: $220,500
Name: SPC hopper
Cost category: Capital cost
Cost: $10,650
Quantity: 5
Total cost: $53,250
Sulfur Polymer
Cement hoppers
Off-gas
piping
Mass of sodium sulfide consumed per year: 60,606 kg
Mass of sulfur polymer cement consumed per year: 1,969,697 kg
Name: Sodium sulfide
Cost category: Bulk material cost (O&M)
Unit cost: 10.53 $/kg delivered
Quantity consumed per year: 60,606 kg
Total cost: $638,182
Name: Sulfur polymer cement
Cost category: Bulk material cost (O&M)
Unit cost: $0.260 per kg
Quantity consumed per year: 1,969,697 kg
Total cost: $512,121
Off-gas
Valves
Vertical Cone
Mixer-Dryer
Heat Transfer
System Piping
Name: Sodium sulfide tank
Cost category: Capital cost
Cost: $557
Quantity: 1
Total cost: $557
Name: Sodium sulfide pump
Cost category: Capital cost
Cost: $15,000
Quantity: 1
Total cost: $15,000
Name: Sodium sulfide feed valves
Cost category: Capital cost
Cost: $330
Quantity: 5
Total cost: $1,650
Name: Mixer
Cost category: Capital cost
Cost: $180,000
Quantity: 5
Total cost: $900,000
Appendix C-Option A costs_Final.xls
-------
Treatment Proc Dia
WASTE VOLUME
Mass of mecury processed in one batch:
Mass of mercury processed per year:
Waste from mixers
525 kg/batch
1,000 tons/year
1,000,000 kg/year
Mass of waste produced per year: 3,030,303 kg/year
Volume increase from mercury to waste product:
16.5 times
Volume of mercury processed 73,643 liters/year
Volume of waste produced: 1,215,112 liters/year
320,999 gallons/year
Density of waste:
Weight of waste in one barrel if completely filled:
Limit barrels to 1000 Ib of waste:
Weight of loaded barrel (include empty barrel weight of 34 kg)
Required number of 55 gallon barrels
2.5 kg/L
1145 Ib
453.6 kg waste per barrel
487.6 kg
1075 Ib
6,681 barrels/year
Waste Drums
Name: 55 gallon barrels
Cost category: O&M
Cost per barrel: $33
Barrels per year: 6,681
Annual cost: $220,462
Forklift
Name: Forklift
Cost category: Capital cost
Cost: $25,000
Quantity: 1
Total cost: $25,000
Staff
Operators
Maintenance Tech
Logistics/Shipping
Operations Supervisor
Process Engineer
Administrative Assistant
I&C Tech
Plant Manager
Lab Tech
QA / Health & Safety Coordinator
Qty
8
1
2
2
1
1
1
1
2
2
Salary
$45,227
$66,162
$37,306
$73,664
$89,127
$45,727
$66,581
$133,022
$67,012
$67,012
Total
$361,816
$66,162
$74,612
$147,328
$89,127
$45,727
$66,581
$133,022
$134,024
$134,024
ENERGY COSTS
Name Load (kW)
Mixer motor 150
Heater 72
Ventilation vacuum pump 4
Forklift 75
Miscellaneous
Qty Total Load (kW)
5
5
1
1
Total
750
360
4
75
178
1,367
Energy used 4,550,541 kW-hours
Price of energy 0.10 $/kw-hr
Cost of energy (per year): $455,054
Total
$1,252,423
Appendix C-Option A costs_Final.xls
-------
Treatment Proc Dia
Fluid heat transfer system
with piping to/from jackets
on mixers
t
Heater
Pump
Name: Heater
Cost category: Capital cost
Cost: $30,000
Quantity: 5
Total cost: $150,000
Name: Chiller
Cost category: Capital cost
Cost: $5,366
Quantity: 1
Total cost: $5,366
Ventilation System (draws
suction from each mixer)
Water-
cooled trap
Chiller
HEPA
filter
Vacuum
pump
Name: Vacuum pump
Cost category: Capital cost
Cost: $5,987
Quantity: 1
Total cost: $5,987
Liquid nitrogen-
cooled trap
Activated
charcoal filter
Condensate
Vessel
Recycle back
to process
Name: Liquid nitrogen-cooled trap
Cost category: Capital cost
Cost: $627
Quantity: 1
Total cost: $627
Name: HEPA filter
Cost category: Capital cost
Cost: $307
Quantity: 1
Total cost: $307
Name: Off-gas piping/ducts
Cost category: Capital cost
Cost: $5,065
Quantity: 1
Total cost: $5,065
Name: Carbon filter
Cost category: Capital cost
Cost: $47
Quantity: 1
Total cost: $47
Name: Condenser
Cost category: Capital cost
Cost: $4,186
Quantity: 1
Total cost: $4,186
Appendix C-Option A costs_Final.xls
-------
Treatment Cap Costs (fixed)
Cost Element
Major Equipment
Sodium sulfide tank
Sodium sulfide pump
Sodium sulfide feed valves
Mixers
SPC Feeder
SPC Hopper
Condenser
Liquid nitrogen-cooled trap
Chiller
HEPA filter
Carbon filter
Vacuum pump
Off-gas piping/ducts
Heater
Forklift
Crane
Subtotal: Major Equipment
Allowance for equipment not yet identified
Subtotal: Major Equipment + Allowance
Estimate
Min
$1,465,542
$146,554
$1,612,096
Best
$557
$15,000
$1,650
$900,000
$220,500
$53,250
$4,186
$627
$5,366
$307
$47
$5,987
$5,065
$150,000
$25,000
$78,000
$1 ,465,542
$219,831
$1,685,373
Max
$1,465,542
$293,108
$1,758,650
Building site preparation
Building construction, services installation
Subtotal: Building
$128,968
$419,145
$548,113
$252,806
$514,039
$766,845
$386,903
$615,528
$1,002,431
Cost to install major equipment $628,717) $691,003) $756,220
Piping
Structural foundations (steel, concrete)
Electrical
Instruments
Auxiliaries
$483,629
$451,387
$128,968
$209,572
$773,806
$581,454
$471,904
$210,672
$219,098
$867,967
$685,874
$492,422
$298,971
$228,625
$967,258
Subtotal: Physical Plant) $4,836,288) $5,494,316) $6,190,448
Other field expenses
Engineering
$564,234
$564,234
$657,295
$657,295
$756,220
$756,220
Subtotal: Direct Plant Cost) $5,964,755) $6,808,907) $7,702,887
Initial Start-Up Costs
Fees, overhead, and profit
Contingency
$119,295
$145,089
$628,717
$885,158
$219,098
$657,295
$1,848,693
$298,971
$685,874
Total
$6,857,856
$8,570,459
$10,536,424
Appendix C-Option A costs_Final.xls
C-5
-------
Treatment Cap Costs (mob)
Cost element
Major Equipment
Sodium sulfide tank
Sodium sulfide pump
Sodium sulfide feed valves
Mixers
SPC Feeder
SPC Hopper
Condenser
Liquid nitrogen-cooled trap
Chiller
HEPA filter
Carbon filter
Vacuum pump
Off-gas piping/ducts
Heater
Forklift
Crane
Subtotal: Major Equipment
Allowance for equipment not yet identified
Subtotal: Major Equipment + Allowance
Estimate
Min
$1,465,542
$146,554
$1,612,096
Best
$557
$15,000
$1,650
$900,000
$220,500
$53,250
$4,186
$627
$5,366
$307
$47
$5,987
$5,065
$150,000
$25,000
$78,000
$1,465,542
$219,831
$1,685,373
Max
$1 ,465,542
$293,108
$1,758,650
Steel for skids
Cost to assemble major equipment skids
Subtotal: Skids
$451,387
$419,145
$870,532
$471,904
$460,669
$932,573
$492,422
$504,146
$996,568
Piping
Electrical
Instruments
Auxiliaries
$483,629
$128,968
$209,572
$773,806
$581,454
$210,672
$219,098
$867,967
$685,874
$298,971
$228,625
$967,258
Subtotal: Physical Plant) $4,078,603| $4,497,1 37| $4,935,945
Engineering
$1,128,467| $1,314,591
$1,512,439
Subtotal: Direct Plant Cost| $5,207,070| $5,81 1 ,728| $6,448,384
Initial Start-Up Costs
Fees, overhead, and profit
Contingency
$104,141
$145,089
$628,717
$755,525
$219,098
$657,295
$1,547,612
$298,971
$685,874
Total
$6,085,017
$7,443,647
$8,980,840
Appendix C-Option A costs_Final.xls
C-6
-------
Treatment O&M
Cost Element
Sodium sulfide
Sulfur Polymer Cement
Barrels
Staff
Energy
Subtotal: direct costs
Estimated Cost (per year)
Min
$638,182
$512,121
$220,462
$1,252,423
$455,054
$3,078,242
Best
$638,182
$512,121
$220,462
$1,252,423
$455,054
$3,078,242
Max
$638,182
$512,121
$220,462
$1,252,423
$455,054
$3,078,242
Flask disposal
Maintenance & Repairs
Insurance
Property tax
Subtotal: indirect costs
$440,000
$32,242
$16,121
$32,242
$520,605
$440,000
$101,122
$16,854
$33,707
$591,684
$440,000
$175,865
$17,587
$35,173
$668,625
Other overhead
Fee
Contingency
$197,937
$719,769
$1,403,550
$201 ,846
$733,985
$1,431,271
$206,078
$749,373
$1,461,278
Total
$5,920,103
$6,037,028
$6,163,596
Appendix C-Option A costs_Final.xls
C-7
-------
Facility Relocation Costs
Cost Element
Transportation of equipment
Assembling treatment process lines
Start-up
Contingency
Total
Estimated Cost (per move)
Min
$209,572
$10,414
$85,795
$305,781
Best
$230,334
$75,552
$119,296
$425,183
Max
$252,073
$154,761
$158,665
$565,500
Appendix C-Option A costs_Final.xls
C-8
-------
Macroencap Proc Dia
Crane
(moves ARROW-PAK tubes)
Name: Crane
Cost category: Capital cost
Cost: $78,000
Quantity: 1
Total cost: $78,000
Barrel loaded
with waste
Arrow-PAK Tube
Waste loading rack
Forklift with loading
plunger
Name: Forklift
Cost category: Capital cost
Cost: $25,000
Quantity: 1
Total cost: $25,000
Name: HOPE pipes
Cost category: Materials (O&M)
Cost ft of pipe: $45
Barrels per year: 6,681
Height of barrel: 2.92ft
Feet of pipe per year: 19,485
Annual cost:
Name: Waste loading rack
Cost category: Capital cost
Cost: $2,400
Quantity: 1
Total cost: $2,400
Appendix C-Option A costs_Final.xls
-------
Macroencap Proc Dia
ARROW-PAK Tube Capacity
Arrow-Pak tube weight limit 9500 Ib
Weight of empty tube 950 Ib
Weight of loaded 55-gallon barrel 1075 Ib
Number of barrels allowed by weight limit 7
Arrow-Pak tube length limit (without endcaps) 22 ft
Length of barrel 34 in
Number of barrels allowed by length limit 7
Fusion Equipment
Name: Fusion equipment
Cost category: Capital cost
Cost: $3,500
Quantity: 1
Total cost: $3,500
Endcaps
Name: HOPE endcaps
Cost category: Materials (O&M)
HOPE endcaps per year: 1,909
Cost per endcap: $250
Annual cost: $477,190
Staff
Operators
Fusion Specialist
Supervisor
Loading Forman
Total
Qty
6
2
2
2
Burdened Salary
$45,227
$66,162
$73,664
$73,664
Total
$271,362
$132,324
$147,328
$147,328
$698,342
ENERGY COSTS
Name Load (kW)
Fusion equipment 150
Forklift 75
Miscellaneous
Qty
Total Load (kW)
1 150
1 75
34
Total 259
Energy used 861,120 kW-hours
Price of energy 0.10 $/kw-hr
Cost of energy (per year): $86,112
Appendix C-Option A costs_Final.xls
-------
Macroencap Proc Dia
Crane
(moves ARROW-PAK tubes)
Name: Crane
Cost category: Capital cost
Cost: $78,000
Quantity: 1
Total cost: $78,000
Transport truck
Name: Chocks
Cost category: Capital cost
Cost: $43
Quantity: 20
Total cost: $851
Loaded Arrow-PAK tubes
Chocks for tube storage
Appendix C-Option A costs_Final.xls
-------
Macroencap Cap Costs (fixed)
Cost Element
Major Equipment
Waste loading rack
Forklift with loading plunger
ARROW-PAK handling crane
Fusion equipment
Loading crane
Chocks
Subtotal: Major Equipment
Allowance for equipment not yet identified
Subtotal: Major Equipment + Allowance
Building site preparation
Building construction, services installation
Subtotal: Building
Cost to install major equipment
Subtotal: Physical Plant
Other field expenses
Engineering
Subtotal: Direct Plant Cost
Initial Start-Up Costs
Fees, overhead, and profit
Contingency
Total
Estimate
Min
$187,751
$18,775
$206,526
$16,522
$53,697
$70,219
$39,240
$315,985
$20,653
$72,284
$408,922
$8,178
$61,958
$53,697
$532,755
Best
$2,400
$25,000
$78,000
$3,500
$78,000
$851
$187,751
$28,163
$215,914
$32,387
$65,854
$98,241
$45,342
$359,496
$23,751
$84,206
$467,453
$60,769
$68,013
$56,138
$652,372
Max
$187,751
$37,550
$225,301
$49,566
$78,855
$128,422
$51,819
$405,542
$27,036
$96,880
$529,458
$127,070
$74,349
$58,578
$789,455
Appendix C-Option A costs_Final.xls
C-12
-------
Macroencap Cap Costs (mob)
Cost Element
Major Equipment
Waste loading rack
Forklift with loading plunger
ARROW-PAK handling crane
Fusion equipment
Loading crane
Chocks
Subtotal: Major Equipment
Allowance for equipment not yet identified
Subtotal: Major Equipment + Allowance
Cost to assemble major equipment skids
Subtotal: Physical Plant
Other field expenses
Engineering
Subtotal: Direct Plant Cost
Initial Start-Up Costs
Fees, overhead, and profit
Contingency
Total
Estimate
Min
$187,751
$18,775
$206,526
$26,229
$232,755
$20,653
$72,284
$325,692
$6,514
$61,958
$53,697
$447,860
Best
$2,400
$25,000
$78,000
$3,500
$78,000
$851
$187,751
$28,163
$215,914
$30,228
$246,142
$23,751
$84,206
$354,098
$46,033
$68,013
$56,138
$524,282
Max
$187,751
$37,550
$225,301
$34,471
$259,772
$27,036
$96,880
$383,688
$92,085
$74,349
$58,578
$608,701
Appendix C-Option A costs_Final.xls
C-13
-------
Macroencap O&M
Cost Element
HOPE pipes (ARROW-PAKs)
End caps
Staff
Energy
Subtotal: direct costs
Maintenance & Repairs
Insurance
Property tax
Subtotal: indirect costs
Other overhead
Fee
Contingency
Total
Estimated Cost (per year)
Min
$876,838
$477,190
$698,342
$86,112
$2,138,482
$4,131
$2,065
$4,131
$10,326
$118,184
$429,762
$838,035
$3,534,790
Best
$876,838
$477,190
$698,342
$86,112
$2,138,482
$12,955
$2,159
$4,318
$19,432
$118,685
$431,583
$841,587
$3,549,769
Max
$876,838
$477,190
$698,342
$86,112
$2,138,482
$22,530
$2,253
$4,506
$29,289
$119,227
$433,554
$845,431
$3,565,984
Appendix C-Option A costs_Final.xls
C-14
-------
Appendix D
Option B Process
Input Information for Cost Estimates
This appendix provides input that was used to estimate the capital and O&M costs for the the Option B process,
together with the macroencapsulation process.
Any costs quoted in this appendix are point estimates.
They were subsequently assigned uncertainty distributions as described in Section 4.5
and run through a Crystal Ball Monte Carlo analysis.
Appendix D - Option B costs_Final.xls D-1
-------
Treatment Proc Dia
PROCESS CAPACITY
Mercury processed per batch 375 kg
Batches per mixer-shift 3
Number of mixers 5
Work week 5 days
Shifts per day 1
Work year 260 shifts/year
Utilization 80%
Equipment work year 208 shifts/year
Annual mercury processing capacity 1,170 tons/year
Required mercury processing throughput: 1,000 tons/year
MERCURY, REAGENT, AND WASTE RATIOS
In each batch mixture, % (by mass) of:
Mercury: 67%
Polysulfide: 3%
Sulfur: 30%
Mercury processed per batch: 375 kg
Polysulfide per batch: 16.8 kg
Sulfur per batch: 168kg
Total batch mass: 560 kg
Crane
Mercury flask
Sulfur hoppers
u u u
REAGENT CONSUMPTION
Mass of mecury processed in one batch: 375 kg
Mass of mercury processed per year: 1,000 tons/year
1,000,000 kg/year
Mass of polysulfide consumed per year:
Mass of sulfur consumed per year:
44,776 kg
447,761 kg
Polysulfide
Valves
Pump
Name: Polysulfide
Cost category: Bulk material cost (O&M)
Unit cost: 0.14 $/kg delivered
Quantity consumed per year: 44,776 kg
Total cost:
Name: Sulfur
Cost category: Bulk material cost (O&M)
Unit cost: 0.37 $/kg delivered
Quantity consumed per year: 447,761 kg
Total cost: $165,672
Name: Polysulfide pump
Cost category: Capital cost
Cost: $3,587
Quantity: 1
Total cost: $3,587
Name: Sulfur hoppers
Cost category: Capital cost
Cost: $26,400
Quantity: 5
Total cost: $132,000
Name: Crane
Cost category: Capital cost
Cost: $78,000
Quantity: 1
Total cost: $78,000
Mixers
Name: Polysulfide feed valves
Cost category: Capital cost
Cost: $760
Quantity: 5
Total cost: $3,800
Name: Mixer
Cost category: Capital cost
Cost: $65,000
Quantity: 5
Total cost: $325,000
Appendix D - Option B costs_Final.xls
D-2
-------
Treatment Proc Dia
Waste from mixers
WASTE VOLUME
Mass of mecury processed in one batch:
Mass of mercury processed per year:
Mass of waste produced per year:
Density of waste:
Volume of waste produced:
Required number of 55 gallon barrels
Weight of each barrel (includes empty barrel weight of 34 kg)
375kg
1,000 tons/year
1,000,000 kg/year
1,492,537 kg
1.78 kg/L
838,504 liters
221,508 gallons
405 kg
892 Ib
Waste Drums
Name: 55 gallon barrels
Cost category: O&M
Cost per barrel: $33
Barrels per year: 4,027
Annual cost: $132,905
Forklift
Name: Forklift
Cost category: Capital cost
Cost: $25,000
Quantity: 1
Total cost: $25,000
Staff
Operators
Maintenance Tech
Logistics/Shipping
Operations Supervisor
Process Engineer
Administrative Assistant
I&C Tech
Plant Manager
Lab Tech
QA / Health & Safety Coordinator
Total
Qty Burdened Salary Total (per year)
4
1
1
1
1
1
1
1
1
1
13
$45,227
$66,162
$37,306
$73,664
$89,127
$45,727
$66,581
$133,022
$67,012
$67,012
$180,908
$66,162
$37,306
$73,664
$89,127
$45,727
$66,581
$133,022
$67,012
$67,012
$826,521
ENERGY COSTS
Name Load (kW)
150
72
Qty Total Load (kW)
Mixer motor
Heater
Ventilation blower
Forklift
Miscellaneous
4
75
5
5
1
1
Total
750
360
4
75
178
1,367
Energy used 2,275,270 kW-hours
Price of energy 0.10 $/kw-hr
Cost of energy (per year): $227,527
Appendix D - Option B costs_Final.xls
D-3
-------
Treatment Proc Dia
Water heater and piping to/
from jackets on mixers
Name: Water heater
Cost category: Capital cost
Cost: $2,769
Quantity: 1
Total cost: $2,769
Name: Piping for water
Cost category: Capital cost
Cost: $4,270
Quantity: 1
Total cost: $4,270
Piping
Ventilation System (draws
suction from each mixer)
Name: Ventilation System Ducts
Cost category: Capital cost
Cost: $5,065
Quantity: 1
Total cost: $5,065
HEPA Filter
Carbon Filter
€?-
Blower
Knockout drum
Name: Knockout drum
Cost category: Capital cost
Cost: $6,300
Quantity: 1
Total cost: $6,300
Name: HEPA filter
Cost category: Capital cost
Cost: $307
Quantity: 1
Total cost: $307
Name: Carbon filter
Cost category: Capital cost
Cost: $47
Quantity: 1
Total cost: $47
Name: Blower
Cost category: Capital cost
Cost: $5,987
Quantity: 1
Total cost: $5,987
Appendix D - Option B costs_Final.xls
D-4
-------
Treatment Cap Costs (fixed)
Cost Element
Major Equipment
Polysulfide pump
Polysulfide feed valves
Sulfur hoppers
Mixers
Knockout drum
HEPA filter
Carbon filter
Blower
Ventilation System duct
Water heater
Forklift
Crane
Subtotal: Major Equipment
Allowance for equipment not yet identified
Subtotal: Major Equipment + Allowance
Estimate
Min
$587,862
$58,786
$646,648
Best
$3,587
$3,800
$132,000
$325,000
$6,300
$307
$47
$5,987
$5,065
$2,769
$25,000
$78,000
$587,862
$88,179
$676,041
Max
$587,862
$117,572
$705,434
Building site preparation
Building construction, services installation
Subtotal: Building
$51,732
$168,128
$219,860
$101,406
$206,193
$307,599
$155,196
$246,902
$402,097
Cost to install major equipment
$252,193| $277,177| $303,337
Piping
Structural foundations (steel, concrete)
Electrical
Instruments
Auxiliaries
$193,994
$181,061
$51,732
$84,064
$310,391
$233,234
$189,291
$84,505
$87,885
$348,161
$275,119
$197,522
$119,924
$91,706
$387,989
Subtotal: Physical Plant| $1,939,9441 $2,203,894| $2,483,128
Other field expenses
Engineering
$226,327
$226,327
$263,656
$263,656
$303,337
$303,337
Subtotal: Direct Plant Cost| $2,392,597| $2,731 ,206| $3,089,801
Initial Start-Up Costs
Fees, overhead, and profit
Contingency
$47,852
$58,198
$252,193
$355,057
$87,885
$263,656
$741,552
$119,924
$275,119
Total
$2,750,840
$3,437,804
$4,226,397
Appendix D - Option B costs_Final.xls
D-5
-------
Treatment Cap Costs (mob)
Cost element
Major Equipment
Polysulfide pump
Polysulfide feed valves
Sulfur hoppers
Mixers
Knockout drum
HEPA filter
Carbon filter
Blower
Ventilation System duct
Water heater
Forklift
Crane
Subtotal: Major Equipment
Allowance for equipment not yet identified
Subtotal: Major Equipment + Allowance
Estimate
Min
$587,862
$58,786
$646,648
Best
$3,587
$3,800
$132,000
$325,000
$6,300
$307
$47
$5,987
$5,065
$2,769
$25,000
$78,000
$587,862
$88,179
$676,041
Max
$587,862
$117,572
$705,434
Steel for skids
Cost to assemble major equipment skids
Subtotal: Skids
$181,061
$168,128
$349,190
$189,291
$184,785
$374,076
$197,522
$202,224
$399,746
Piping
Electrical
Instruments
Auxiliaries
$193,994
$51,732
$84,064
$310,391
$233,234
$84,505
$87,885
$348,161
$275,119
$119,924
$91,706
$387,989
Subtotal: Physical Plant) $1 ,636,01 9| $1 ,803,903| $1 ,979,91 8
Engineering
$452,654| $527,312| $606,673
Subtotal: Direct Plant Cost| $2,088,673| $2,331 ,21 5| $2,586,592
Initial Start-Up Costs
Fees, overhead, and profit
Contingency
$41,773
$58,198
$252,193
$303,058
$87,885
$263,656
$620,782
$119,924
$275,119
Total
$2,440,837
$2,985,814
$3,602,417
Appendix D - Option B costs_Final.xls
D-6
-------
Treatment O&M
Cost Element
Polysulfide
Sulfur
Barrels
Staff
Energy
Subtotal: direct costs
Estimated Cost (per year)
Min
$6,269
$165,672
$132,905
$826,521
$227,527
$1,358,893
Best
$6,269
$165,672
$132,905
$826,521
$227,527
$1,358,893
Max
$6,269
$165,672
$132,905
$826,521
$227,527
$1,358,893
Flask disposal
Maintenance & Repairs
Insurance
Property tax
Subtotal: indirect costs
$440,000
$12,933
$6,466
$12,933
$472,332
$440,000
$40,562
$6,760
$13,521
$500,844
$440,000
$70,543
$7,054
$14,109
$531,706
Other overhead
Fee
Contingency
$100,717
$366,245
$714,178
$102,286
$371,947
$725,297
$103,983
$378,120
$737,334
Total
$4,129,413
$4,193,706
$4,263,302
Appendix D - Option B costs_Final.xls
D-7
-------
Fclty Reloc Costs
Cost Element
Transportation of equipment
Assembling treatment process lines
Start-up
Contingency
Total
Estimated Cost (per move)
Min
$84,064
$4,177
$34,414
$122,656
Best
$92,392
$30,306
$47,852
$170,550
Max
$101,112
$62,078
$63,644
$226,835
Appendix D - Option B costs_Final.xls
D-8
-------
Macroencap Proc Dia
Crane
(moves ARROW-PAK tubes)
Name: Crane
Cost category: Capital cost
Cost: $78,000
Quantity: 1
Total cost: $78,000
Barrel loaded
with waste
Arrow-PAK Tube
"i—r
Waste loading rack
Forkliftwith loading
plunger
Name: HOPE pipes
Cost category: Materials (O&M)
Name: Forklift
Cost category: Capital cost
Cost: $25,000
Quantity: 1
Total cost: $25,000
Cost ft of pipe:
Barrels per year:
Height of barrel:
Feet of pipe per year:
Annual cost:
$45
4,027
2.92 ft
11,747
$528,598
Name: Waste loading rack
Cost category: Capital cost
Cost: $2,400
Quantity: 1
Total cost: $2,400
Appendix D - Option B costs_Final.xls
D-9
-------
Macroencap Proc Dia
ARROW-PAK Tube Capacity
Arrow-Pak tube weight limit 9500 Ib
Weight of empty tube 950 Ib
Weight of loaded 55-gallon barrel 892 Ib
Number of barrels allowed by weight limit 9
Arrow-Pak tube length limit (without endcaps) 22 ft
Length of barrel 34 in
Number of barrels allowed by length limit 7
Fusion Equipment
Name: Fusion equipment
Cost category: Capital cost
Cost: $3,500
Quantity: 1
Total cost: $3,500
Endcaps
Name: HOPE endcaps
Cost category: Materials (O&M)
HOPE endcaps per year: 1,007
Cost per endcap: $250
Annual cost: $251,713
Staff
Operators
Fusion Specialist
Supervisor
Loading Forman
Total
Qty
3
1
1
1
Burdened Salary
$45,227
$66,162
$73,664
$73,664
Total
$135,681
$66,162
$73,664
$73,664
$349,171
ENERGY COSTS
Name Load (kW)
Fusion equipment 150
Forklift 75
Miscellaneous
Qty
Total Load (kW)
1 150
1 75
34
Total 259
Energy used 430,560 kW-hours
Price of energy 0.10 $/kw-h r
Cost of energy (per year): $43,056
Appendix D - Option B costs_Final.xls
D-10
-------
Macroencap Proc Dia
Crane
(moves ARROW-PAK tubes)
Name: Crane
Cost category: Capital cost
Cost: $78,000
Quantity: 1
Total cost: $78,000
Transport truck
Name: Chocks
Cost category: Capital cost
Cost: $43
Quantity: 20
Total cost: $851
Loaded Arrow-PAK tubes
Chocks for tube storage
Appendix D - Option B costs_Final.xls
D-11
-------
Macroencap Cap Costs (fixed)
Cost Element
Major Equipment
Waste loading rack
Forklift with loading plunger
ARROW-PAK handling crane
Fusion equipment
Loading crane
Chocks
Subtotal: Major Equipment
Allowance for equipment not yet identified
Subtotal: Major Equipment + Allowance
Building site preparation
Building construction, services installation
Subtotal: Building
Cost to install major equipment
Subtotal: Physical Plant
Other field expenses
Engineering
Subtotal: Direct Plant Cost
Initial Start-Up Costs
Fees, overhead, and profit
Contingency
Total
Estimate
Min
$187,751
$18,775
$206,526
$16,522
$53,697
$70,219
$39,240
$315,985
$20,653
$72,284
$408,922
$8,178
$61,958
$53,697
$532,755
Best
$2,400
$25,000
$78,000
$3,500
$78,000
$851
$187,751
$28,163
$215,914
$32,387
$65,854
$98,241
$45,342
$359,496
$23,751
$84,206
$467,453
$60,769
$68,013
$56,138
$652,372
Max
$187,751
$37,550
$225,301
$49,566
$78,855
$128,422
$51,819
$405,542
$27,036
$96,880
$529,458
$127,070
$74,349
$58,578
$789,455
Appendix D - Option B costs_Final.xls
D-12
-------
Macroencap Cap Costs (mob)
Cost Element
Major Equipment
Waste loading rack
Forklift with loading plunger
ARROW-PAK handling crane
Fusion equipment
Loading crane
Chocks
Subtotal: Major Equipment
Allowance for equipment not yet identified
Subtotal: Major Equipment + Allowance
Cost to assemble major equipment skids
Subtotal: Physical Plant
Other field expenses
Engineering
Subtotal: Direct Plant Cost
Initial Start-Up Costs
Fees, overhead, and profit
Contingency
Total
Estimate
Min
$187,751
$18,775
$206,526
$26,229
$232,755
$20,653
$72,284
$325,692
$6,514
$61,958
$53,697
$447,860
Best
$2,400
$25,000
$78,000
$3,500
$78,000
$851
$187,751
$28,163
$215,914
$30,228
$246,142
$23,751
$84,206
$354,098
$46,033
$68,013
$56,138
$524,282
Max
$187,751
$37,550
$225,301
$34,471
$259,772
$27,036
$96,880
$383,688
$92,085
$74,349
$58,578
$608,701
Appendix D - Option B costs_Final.xls
D-13
-------
Macroencap O&M
Cost Element
HOPE pipes (ARROW-PAKs)
End caps
Staff
Energy
Subtotal: direct costs
Maintenance & Repairs
Insurance
Property tax
Subtotal: indirect costs
Other overhead
Fee
Contingency
Total
Estimated Cost (per year)
Min
$528,598
$251,713
$349,171
$43,056
$1,172,538
$4,131
$2,065
$4,131
$10,326
$65,058
$236,573
$461,317
$1,945,812
Best
$528,598
$251,713
$349,171
$43,056
$1,172,538
$12,955
$2,159
$4,318
$19,432
$65,558
$238,394
$464,868
$1,960,791
Max
$528,598
$251,713
$349,171
$43,056
$1,172,538
$22,530
$2,253
$4,506
$29,289
$66,100
$240,365
$468,713
$1,977,006
Appendix D - Option B costs_Final.xls
D-14
-------
Appendix E
Input to Monofill Costs - Option A Process
This appendix provides input that was used to estimate the capital and O&M costs for the monofill associated with the Option A treatment process.
Any costs quoted in this appendix are point estimates.
They were subsequently assigned uncertainty distributions as described in Section 4.5 and run through a Crystal Ball Monte Carlo analysis.
Appendix E - Option A Monofill_Final.xls E-1
-------
Dimensions
Dimensions required for a five year cell: Without macroencapsulation With macroencapsulation
Length of disposal area 207 ft 227 ft
Width of disposal area 207ft 218ft
Area required for storage
Storage volume depth
Depth below grade
Bottom liner thickness
Run-off ditch depth
Width at bottom of run-off ditch
Run-off ditch length
Run-off ditch volume
42,849 ftA2
0.98 acres
15ft
7.5ft
7 ft
6ft
1 ft
852 ft
35,784 ftA3
1,325 ydA3
49,345 ftA2
1.13 acres
15ft
7.5ft
7ft
6ft
1 ft
912.8ft
38,336 ftA3
1,420 ydA3
Size of a cell without macroencapsulation
Height of one 55-gallon drum 34 in
Diameter of one 55-gallon drum 23 in
Fill above and below each layer 5.5 in
Height of a layer 45 in
Stack drums 4 high
Thickness of waste layer 15.0 ft
Thickness alloted for waste layer 15 ft
Barrels per year 6,681
Barrels in five years 33,405
Barrels per layer required in the cell 8,351.25
One layer is:
Distance between barels in the square
Distance one barrel occupies
Length of the side of a cell
92 by
92 barrels
4 in
27 in
207ft
Size of a cell with macroencapsulation
Barrels per Arrow-Pak tube
Length of one Arrow-Pak tube
Diameter of one Arrow-Pak tube
Fill above and below each layer
Height of a layer
Stack tubes
Thickness of waste layer
Thickness alloted for waste layer
Barrels per year
Barrels in five years
Tubes in five years
Required tubes per layer
Distance between tubes
Area one tube occupies
One layer is:
Lengths of the sides of the cell
7
20.3ft
26 in
5 in
36 in
5 high
15.0ft
15ft
6,681
33,405
4,772
954
4 in
20.6 ft by
30 in
11 tubes long by
87 tubes wide
227 ft by
218ft
Appendix E - Option A Monofill_Final.xls
E-2
-------
Labor & Materials
Summary of construction costs
Disposal volume excavation
Run-on, run-off controls
Bottom Liner
Waste and Fill Layer
Top Liner
Groundwater Monitoring Wells
TOTAL
Without macroencapsulation
$110,713
$11,186
$681,580
$13,759
$221,595
$96,670
$1,135,503
With macroencapsulation
$126,434
$11,983
$775,689
$15,845
$252,192
$96,670
$1,278,813
Disposal Volume Excavation
Excavation required for disposal voume
Unit cost for excavation
Cost $
708,354 ft"3
26,235 yd"3
4.22 $/yd"3
110,713.11 $
808,937 ft"3
29,961 yd"3
4.22 $/yd"3
126,433.84
Run-on, run-off controls
Run-off ditch
Excavation required for run-off ditch
Unit cost for excavation
Cost i
35,784 ft»3
1,325 yd»3
4.22 $/yd»3
5,592.91
Cost of building berm
Assume excavated soil for run-off ditch is used for berm
Berm volume 1,325 yd"3
Unit cost for building 4.22 $/yd"3
Berm cost $ 5,592.91
38,336 ft»3
1,420 ft»3
4.22 $/yd»3
5,991.70
1,420 yd"3
4.22 $/yd»3
5,991.70
Appendix E - Option A Monofill_Final.xls
-------
Labor & Materials
Bottom Liner
Area required for storage + liner slope
Cost of compacted clay
Clay thickness
Clay volume
Unit cost
Cost of compacted clay $
Geotextile support fabric
Layers required
Area required
Unit cost
Cost for geotextile support fabric $
Geotextile filter fabric
Layers required
Area required
Unit cost
Cost for geotextile filter fabric $
HOPE liners
Layers required
Area required
Unit cost
Cost for HOPE liner $
Gravel drainage layers
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted gravel $
Compacted fill soil
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted soil $
51,716 ft"2
3ft
155,148 ft"3
5,746 yd"3
27.63 $/yd"3
158,768.49 $
3
51,716 ft"2
0.26 $/ft"2
40,338.57 $
1
51,716 ft"2
0.13 $/ft"2
6,723.10 $
2
51,716 ft"2
0.53 $/ft"2
54,819.09 $
2
1 ft
51,716 ft"2
103,432 ft"3
3,831 yd"3
12.57 $/yd"3
48,153.45 $
1
2ft
51,716 ft"2
103,432 ft"3
3,831 yd"3
5.78 $/yd"3
22,142.16 $
58,857 ft"2
3ft
176,570 ft"3
6,540 yd"3
27.63 $/yd"3
180,690.32
3
58,857 ft"2
0.26 $/ft"2
45,908.29
1
58,857 ft"2
0.13 $/ft"2
7,651.38
2
58,857 ft"2
0.53 $/ft"2
62,388.19
2
1 ft
58,857 ft"2
117,714 ft"3
4,360 yd"3
12.57 $/yd"3
54,802.20
1
2ft
58,857 ft"2
117,714 ft"3
4,360 yd"3
5.78 $/yd"3
25,199.42
Leachate collection and removal system
Area required
Installed unit cost
Cost $
Leak detection system
Area required
Installed unit cost
Cost $
51,716 ft"2
3.39 $/ft"2
175,317.64 $
51,716 ft"2
3.39 $/ft"2
175,317.64 $
58,857 ft"2
3.39 $/ft"2
199,524.49
58,857 ft"2
3.39 $/ft"2
199,524.49
Waste and Fill Layer
Volume of fill required
Unit cost
Cost of flow/able fill $
64,274 ft»3
2,381 yd»3
5.78 $/yd»3
13,759.29 $
74,018 ft»3
2,741 yd"3
5.78 $/yd»3
15,845.33
Appendix E - Option A Monofill_Final.xls
-------
Labor & Materials
Top Liner
Without macroencapsulation
Area required for storage + liner slope
Cost of compacted clay
Clay thickness
Clay volume
Unit cost
Cost of compacted clay $
Geotextile support fabric
Layers required
Area required
Unit cost
Cost for geotextile support fabric $
Geotextile filter fabric
Layers required
Area required
Unit cost
Cost for geotextile filter fabric $
HOPE liners
Layers required
Area required
Unit cost
Cost for HOPE liner $
Gravel drainage layers
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted gravel $
Compacted fill soil
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted soil $
Compacted top soil
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted soil $
Vegetation to stabilize topsoi
Area required
Unit cost
Cost $
51,716 ft"2
1.5 ft
77,574 ft"3
2,873 yd"3
27.63 $/yd"3
79,384.24
2
51,716 ft"2
0.26 $/ft"2
26,892.38
1
51,716 ft"2
0.13 $/ft"2
6,723.10
1
51,716 ft"2
0.53 $/ft"2
27,409.54
1
0.5 ft
51,716 ft"2
25,858 ft"3
958 yd"3
12.57 $/yd"3
12,038.36
1
3ft
51,716 ft"2
155,148 ft"3
5,746 yd"3
5.78 $/yd"3
33,213.24
1
1 ft
51,716 ft"2
51,716 ft"3
1,915 yd"3
17.68 $/yd"3
33,864.48
51,716 ft"2
1.19 acres
1743.40 $/acre
2,069.83
With macroencapsulation
58,857 ft"2
1.5 ft
88,285 ft"3
3,270 yd"3
27.63 $/yd"3
$ 90,345.16
2
58,857 ft"2
0.26 $/ft"2
$ 30,605.53
1
58,857 ft"2
0.13 $/ft"2
$ 7,651.38
1
58,857 ft"2
0.53 $/ft"2
$ 31,194.09
1
0.5 ft
58,857 ft"2
29,428 ft"3
1,090 yd"3
12.57 $/yd"3
$ 13,700.55
1
3ft
58,857 ft"2
176,570 ft"3
6,540 yd"3
5.78 $/yd"3
$ 37,799.13
1
1 ft
58,857 ft"2
58,857 ft"3
2,180 yd"3
17.68 $/yd"3
$ 38,540.29
58,857 ft"2
1.35 acres
1743.40 $/acre
$ 2,355.62
Groundwater Monitoring Wells
Clusters (three wells) required
Cost per cluster
Cost
24,167.48
96,669.92
24,167.48
96,669.92
Appendix E - Option A Monofill_Final.xls
-------
Direct O&M (filling)
Summary of Annual Direct O&M Costs (filling)
Staff
Groundwater Monitoring
Utilities
Fee
TOTAL
Without
macroencapsulation
$352,991
$4,752
$10,000
$55,162
$422,905
With
macroencapsu lation
$443,097
$4,752
$10,000
$68,677
$526,526
Staff
Operators
Maintenance Tech
Logistics/Shipping
Operations Supervisor
Administrative Assistant
Plant Manager
QA / Health & Safety Coordinator
Burdened Annual
Salary
$45,227
$66,162
$37,306
$73,664
$45,727
$133,022
$67,012
Qty
4
1
1
1
1
1
1
Without macroencapsulation
Annual
utilization
0.58
0.58
0.58
0.58
0.58
0.58
0.58
Totals:
Total
$105,761.60
$38,679.32
$21,809.66
$43,065.11
$26,732.71
$77,766.71
$39,176.25
With macroencapsulation
Annual
utilization
0.73
0.73
0.73
0.73
0.73
0.73
0.73
Total
$132,759
$48,553
$27,377
$54,058
$33,557
$97,618
$49,176
$352,991.35|
$443,097
Groundwater Monitoring
Number of groundwater monitoring wells
Samples per year from each well
Cost for sample analysis
Annual Cost
4
12
$99
$4,752
4
12
$99
$4,752
Shipments per year without macroencapsulation
Truck weight limit
Weight of one barrel loaded with treated mercury
Barrels per truck delivery
Flat bed trailer width
Flat bed trailer length
Area available on flat bed trailer
Area required by one barrel
Area required by barrels in one shipment
Barrels per year
Shipments per year
40,000 Ib
892 Ib
44 barrels
8ft
40ft
320 ftA2
5.4 ftA2
239 ftA2
6681
152
Shipments per year with macroencapsulation
Truck weight limit
Barrels per Arrow-Pak
Weight, one tube w/barrels of treated Hg (empty tube is 950 Ib)
Arrow-Pak tubes per truck delivery
Area required by one Arrow-Pak tube
Area required by tubes in one shipment
Area available on flat bed trailer
Tubes per year
Shipments per year
40,000 Ib
7
7194 Ib
5 tubes
44.0 ftA2
220 ftA2
320 ftA2
954
190.8
Appendix E - Option A Monofill_Final.xls
E-6
-------
O&M (post-closure)
Summary of Post-Closure Costs
Leachate collection and removal system
Leak detection system
Ground water
Utilities
License and bonding fees
Fee
Contingency
Total 30-year Cost
Without macroencapsulation
$10,437
$19,135
$5,940
$30,000
$300,000
$54,827
$42,034
$462,372
With macroencapsulation
$10,437
$19,135
$5,940
$30,000
$300,000
$54,827
$42,034
$462,372
[Cost for one day of operator time for each inspection
$174|
Leachate collection and removal system
First five years
Monitoring per year
Cost per sample
Total cost
12
$174
$10,437
12
$174
$10,437
Leak detection system
First five years
Following twenty-five years
Monitoring per year
Cost per sample
Cost (first five years)
Monitoring per year
Cost per sample
Cost (following twenty-five years)
Total
12
$174
$10,437
2
$174
$8,698
$19,135
12
$174
$10,437
2
$174
$8,698
$19,135
Ground water monitoring
Samples per year
Cost per sample
Total cost
2
$99
$5,940
2
$99
$5,940
Appendix E - Option A Monofill_Final.xls
E-7
-------
Appendix F
Input to Monofill Costs - Option B Process
This appendix provides input that was used to estimate the capital and O&M costs for the monofill associated with the Option B treatment process.
Any costs quoted in this appendix are point estimates.
They were subsequently assigned uncertainty distributions as described in Section 4.5 and run through a Crystal Ball Monte Carlo analysis.
Appendix F - Option B Monofill_Final.xls F-1
-------
Dimensions
Dimensions required for a five year cell: Without macroencapsulation With macroencapsulation
Length of disposal area 160 ft 165 ft
Width of disposal area 1 60 ft 1 80 ft
Area required for storage
Storage volume depth
Depth below grade
Bottom liner thickness
Run-off ditch depth
Width at bottom of run-off ditch
Run-off ditch length
Run-off ditch volume
25,520 ftA2
0.59 acres
15ft
7.5ft
7ft
6ft
1 ft
663ft
27,846 ftA3
1,031 ydA3
29,700 ftA2
0.68 acres
15ft
7.5 ft
7ft
6 ft
1 ft
714.0 ft
29,988 ftA3
1,111 ydA3
Size of a cell without macroencapsulation
Height of one 55-gallon drum 34 in
Diameter of one 55-gallon drum 23 in
Fill above and below each layer 5.5 in
Height of a layer 45 in
Stack drums 4 high
Thickness of waste layer 15.0 ft
Thickness alloted for waste layer 15 ft
Barrels per year 4,027
Barrels in five years 20,135
Barrels per layer required in the cell 5,033.75
One layer is:
Distance between barels in the square
Distance one barrel occupies
Length of the side of a cell
71 by
71 barrels
4 in
27 in
160ft
Size of a cell with macroencapsulation
Barrels per Arrow-Pak tube
Length of one Arrow-Pak tube
Diameter of one Arrow-Pak tube
Fill above and below each layer
Height of a layer
Stack tubes
Thickness of waste layer
Thickness alloted for waste layer
Barrels per year
Barrels in five years
Tubes in five years
Required tubes per layer
Distance between tubes
Area one tube occupies
One layer is:
Lengths of the sides of the cell
7
20.3 ft
26 in
5 in
36 in
5 high
15.0ft
15ft
4,027
20,135
2,876
575
4 in
20.6 ft by
30 in
8 tubes long by
72 tubes wide
165 ft by
180ft
Appendix F - Option B Monofill_Final.xls
F-2
-------
Labor & Materials
Summary of construction costs
Disposal volume excavation
Run-on, run-off controls
Bottom Liner
Waste and Fill Layer
Top Liner
Groundwater Monitoring Wells
TOTAL
Without macroencapsulation
$68,335
$8,704
$426,778
$8,195
$138,754
$96,670
$747,436
With macroencapsulation
$78,646
$9,374
$488,995
$9,537
$158,982
$96,670
$842,205
Disposal Volume Excavation
Excavation required for disposal voume
Unit cost for excavation
Cost $
437,216 ftA3
16,193 ydA3
4.22 $/ydA3
68,335.21 $
503,186 ftA3
18,637 ydA3
4.22 $/ydA3
78,646.15
Run-on, run-off controls
Run-off ditch
Excavation required for run-off ditch
Unit cost for excavation
Cost !
27,846 ftA3
1,031 ydA3
4.22 $/ydA3
4,352.23
$
Cost of building berm
Assume excavated soil for run-off ditch is used for berm
Berm volume 1,031 ydA3
Unit cost for building 4.22 $/ydA3
Berm cost $ 4,352.23 $
29,988 ftA3
1,111 ftA3
4.22 $/ydA3
4,687.01
1,111 ydA3
4.22 $/ydA3
4,687.01
Appendix F - Option B Monofill_Final.xls
F-3
-------
Labor & Materials
Bottom Liner
Area required for storage + liner slope
Cost of compacted clay
Clay thickness
Clay volume
Unit cost
Cost of compacted clay $
Geotextile support fabric
Layers required
Area required
Unit cost
Cost for geotextile support fabric $
Geotextile filter fabric
Layers required
Area required
Unit cost
Cost for geotextile filter fabric $
HOPE liners
Layers required
Area required
Unit cost
Cost for HOPE liner $
Gravel drainage layers
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted gravel $
Compacted fill soil
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted soil $
32,383 ftA2
3ft
97,148 ftA3
3,598 ydA3
27.63 $/ydA3
99,414.38 $
3
32,383 ftA2
0.26 $/ftA2
25,258.38 $
1
32,383 ftA2
0.13 $/ftA2
4,209.73 $
2
32,383 ftA2
0.53 $/ftA2
34,325.49 $
2
1 ft
32,383 ftA2
64,765 ftA3
2,399 ydA3
12.57 $/ydA3
30,151.74 $
1
2ft
32,383 ftA2
64,765 ftA3
2,399 ydA3
5.78 $/ydA3
13,864.52 $
37,103 ftA2
3ft
111,310 ftA3
4,123 ydA3
27.63 $/ydA3
113,907.46
3
37,103 ftA2
0.26 $/ftA2
28,940.66
1
37,103 ftA2
0.13$/ftA2
4,823.44
2
37,103 ftA2
0.53 $/ftA2
39,329.61
2
1 ft
37,103 ftA2
74,207 ftA3
2,748 ydA3
12.57 $/ydA3
34,547.40
1
2 ft
37,103 ftA2
74,207 ftA3
2,748 ydA3
5.78 $/ydA3
15,885.76
Leachate collection and removal system
Area required
Installed unit cost
Cost $
Leak detection system
Area required
Installed unit cost
Cost $
32,383 ftA2
3.39 $/ftA2
109,776.79 $
32,383 ftA2
3.39 $/ftA2
109,776.79 $
37,103 ftA2
3.39 $/ftA2
125,780.55
37,103 ftA2
3.39 $/ftA2
125,780.55
Waste and Fill Layer
Volume of fill required
Unit cost
Cost of flow/able fill $
38,280 ftA3
1,418 ydA3
5.78 $/ydA3
8,194.78 $
44,550 ftA3
1,650 ydA3
5.78 $/ydA3
9,537.00
Appendix F - Option B Monofill_Final.xls
F-4
-------
Labor & Materials
Top Liner
Without macroencapsulation
Area required for storage + liner slope
Cost of compacted clay
Clay thickness
Clay volume
Unit cost
Cost of compacted clay $
Geotextile support fabric
Layers required
Area required
Unit cost
Cost for geotextile support fabric $
Geotextile filter fabric
Layers required
Area required
Unit cost
Cost for geotextile filter fabric $
HOPE liners
Layers required
Area required
Unit cost
Cost for HOPE liner $
Gravel drainage layers
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted gravel $
Compacted fill soil
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted soil $
Compacted top soil
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted soil $
32,383 ftA2
1.5ft
48,574 ftA3
1,799 ydA3
27.63 $/ydA3
49,707.19
2
32,383 ftA2
0.26 $/ftA2
16,838.92
1
32,383 ftA2
0.13 $/ftA2
4,209.73
1
32,383 ftA2
0.53 $/ftA2
17,162.74
1
0.5ft
32,383 ftA2
16,191 ftA3
600 ydA3
12.57$/ydA3
7,537.93
1
3ft
32,383 ftA2
97,148 ftA3
3,598 ydA3
5.78 $/ydA3
20,796.78
1
1 ft
32,383 ftA2
32,383 ftA3
1,199 ydA3
1 7.68 $/ydA3
21,204.56
With macroencapsulation
37,103 ftA2
1.5ft
55,655 ftA3
2,061 ydA3
27.63 $/ydA3
$ 56,953.73
2
37,103 ftA2
0.26 $/ftA2
$ 19,293.77
1
37,103 ftA2
0.13$/ftA2
$ 4,823.44
1
37,103 ftA2
0.53 $/ftA2
$ 19,664.81
1
0.5ft
37,103 ftA2
18,552 ftA3
687 ydA3
12.57$/ydA3
$ 8,636.85
1
3ft
37,103 ftA2
111,310 ftA3
4,123 ydA3
5.78 $/ydA3
$ 23,828.63
1
1 ft
37,103 ftA2
37,103 ftA3
1,374 ydA3
1 7.68 $/ydA3
$ 24,295.86
Vegetation to stabilize topsoil
Area required
Unit cost
Cost $
32,383 ftA2
0.74 acres
1 743.40 $/acre
1 ,296.04
37,103 ftA2
0.85 acres
1 743.40 $/acre
$ 1 ,484.99
Groundwater Monitoring Wells
Clusters (three wells) required
Cost per cluster $
Cost $
4
24,167.48
96,669.92
$
$
4
24,167.48
96,669.92
Appendix F - Option B Monofill_Final.xls
F-5
-------
Direct O&M (filling)
Summary of Annual Direct O&M Costs (filling)
Staff
Groundwater Monitoring
Utilities
Fee
TOTAL
Without
macroencapsulation
$213,653
$4,752
$10,000
$34,261
$262,665
With
macroencapsu lation
$267,066
$4,752
$10,000
$42,273
$324,091
Staff
Operators
Maintenance Tech
Logistics/Shipping
Operations Supervisor
Administrative Assistant
Plant Manager
QA / Health & Safety Coordinator
Burdened Annual
Salary
$45,227
$66,162
$37,306
$73,664
$45,727
$133,022
$67,012
Qty
4
1
1
1
1
1
1
Without macroencapsulation
Annual
utilization
0.35
0.35
0.35
0.35
0.35
0.35
0.35
Totals:
Total
$64,013.60
$23,411.17
$13,200.58
$26,065.72
$16,180.32
$47,069.32
$23,711.94
With macroencapsulation
Annual
utilization
0.44
0.44
0.44
0.44
0.44
0.44
0.44
Total
$80,017
$29,264
$16,501
$32,582
$20,225
$58,837
$29,640
$213,652.66
$267,066
Groundwater Monitoring
Number of groundwater monitoring wells
Samples per year from each well
Cost for sample analysis
Annual Cost
4
12
$99
$4,752
4
12
$99
$4,752
Shipments per year without macroencapsulation
Truck weight limit
Weight of one barrel loaded with treated mercury
Barrels per truck delivery
Flat bed trailer width
Flat bed trailer length
Area available on flat bed trailer
Area required by one barrel
Area required by barrels in one shipment
Barrels per year
Shipments per year
40,000 Ib
892 Ib
44 barrels
8ft
40ft
320 ftA2
5.4 ftA2
239 ftA2
4027
92
Shipments per year with macroencapsulation
Truck weight limit
Barrels per Arrow-Pak
Weight, one tube w/barrels of treated Hg (empty tube is 950 Ib)
Arrow-Pak tubes per truck delivery
Area required by one Arrow-Pak tube
Area required by tubes in one shipment
Area available on flat bed trailer
Tubes per year
Shipments per year
40,000 Ib
7
7194 Ib
5 tubes
44.0 ftA2
220 ftA2
320 ftA2
575
115
Appendix F - Option B Monofill_Final.xls
F-6
-------
O&M (post-closure)
Summary of Post-Closure Costs
Leachate collection and removal system
Leak detection system
Ground water
Utilities
License and bonding fees
Fee
Contingency
Total 30-year Cost
Without macroencapsulation
$10,437
$19,135
$5,940
$30,000
$300,000
$54,827
$42,034
$462,372
With macroencapsulation
$10,437
$19,135
$5,940
$30,000
$300,000
$54,827
$42,034
$462,372
[Cost for one day of operator time for each inspection
$174|
Leachate collection and removal system
First five years
Monitoring per year
Cost per sample
Total cost
12
$174
$10,437
12
$174
$10,437
Leak detection system
First five years
Following twenty-five years
Monitoring per year
Cost per sample
Cost (first five years)
Monitoring per year
Cost per sample
Cost (following twenty-five years)
Total
12
$174
$10,437
2
$174
$8,698
$19,135
12
$174
$10,437
2
$174
$8,698
$19,135
Ground water monitoring
Samples per year
Cost per sample
Total cost
2
$99
$5,940
2
$99
$5,940
Appendix F - Option B Monofill_Final.xls
F-7
-------
Appendix G
Input to Monofill Costs - Option C Process
This appendix provides input that was used to estimate the capital and O&M costs for the monofill associated with the Option C treatment process.
Any costs quoted in this appendix are point estimates.
They were subsequently assigned uncertainty distributions as described in Section 4.5 and run through a Crystal Ball Monte Carlo analysis.
Appendix G - Option C Monofill-Final.xls G-1
-------
Dimensions
Dimensions required for a five year cell: Without macroencapsulation With macroencapsulation
Length of disposal area 223 ft 210 ft
Width of disposal area 223 ft 203 ft
Area required for storage
Storage volume depth
Depth below grade
Bottom liner thickness
Run-off ditch depth
Width at bottom of run-off ditch
Run-off ditch length
Run-off ditch volume
49,618 ftA2
1.14 acres
15ft
7.5ft
7ft
6ft
1 ft
915.0ft
38,430 ftA3
1,423 ydA3
42,611 ftA2
0.98 acres
15ft
7.5ft
7 ft
6ft
1 ft
849.9 ft
35,694 ftA3
1,322 ydA3
Size of a cell without macroencapsulation
Height of one 22-gallon drum
Diameter of one 22-gallon drum
Fill above and below each layer
Height of a layer
Stack drums
Thickness of waste layer
Thickness alloted for waste layer
Barrels per year
Barrels in five years
Barrels per layer required in the cell
One layer is:
Distance between barels in the square
Distance one barrel occupies
Length of the side of a cell
13.6 in
23 in
6 in
25.6 in
7 high
14.9ft
15ft
13,724
68,620
9,802.86
99 by
99 barrels
4 in
27 in
223ft
Size of a cell with macroencapsulation
Barrels per Arrow-Pak tube
Length of one Arrow-Pak tube
Diameter of one Arrow-Pak tube
Fill above and below each layer
Height of a layer
Stack tubes
Thickness of waste layer
Thickness alloted for waste layer
Barrels per year
Barrels in five years
Tubes in five years
Required tubes per layer
Distance between tubes
Area one tube occupies
One layer is:
Lengths of the sides of the cell
9
10.7ft
26 in
5 in
36 in
5 high
15.0ft
15ft
13,724
68,620
7,624
1,525
4 in
11.1 ft by
30 in
19 tubes long by
81 tubes wide
210 ft by
203ft
Appendix G - Option C Monofill-Final.xls
G-2
-------
Labor & Materials
Summary of construction costs
Disposal volume excavation
Run-on, run-off controls
Bottom Liner
Waste and Fill Layer
Top Liner
Groundwater Monitoring Wells
TOTAL
Without macroencapsulation
$127,088
$12,013
$779,591
$15,933
$253,461
$96,670
$1 ,284,755
With macroencapsulation
$110,139
$11,158
$678,144
$13,683
$220,478
$96,670
$1,130,271
Disposal Volume Excavation
Excavation required for disposal voume
Unit cost for excavation
Cost $
813,121 ftA3
30,116 ydA3
4.22 $/ydA3
127,087.81 $
704,678 ftA3
26,099 ydA3
4.22 $/ydA3
110,138.54
Run-on, run-off controls
Run-off ditch
Excavation required for run-off ditch
Unit cost for excavation
Cost !
38,430 ftA3
1,423 ydA3
4.22 $/ydA3
6,006.47
$
Cost of building berm
Assume excavated soil for run-off ditch is used for berm
Berm volume 1,423 ydA3
Unit cost for building 4.22 $/ydA3
Berm cost $ 6,006.47 $
35,694 ftA3
1,322 ftA3
4.22 $/ydA3
5,578.79
1,322 ydA3
4.22 $/ydA3
5,578.79
Appendix G - Option C Monofill-Final.xls
G-3
-------
Labor & Materials
Bottom Liner
Area required for storage + liner slope
Cost of compacted clay
Clay thickness
Clay volume
Unit cost
Cost of compacted clay $
Geotextile support fabric
Layers required
Area required
Unit cost
Cost for geotextile support fabric $
Geotextile filter fabric
Layers required
Area required
Unit cost
Cost for geotextile filter fabric $
HOPE liners
Layers required
Area required
Unit cost
Cost for HOPE liner $
Gravel drainage layers
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted gravel $
Compacted fill soil
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted soil $
59,153 ftA2
3ft
177,459 ftA3
6,573 ydA3
27.63 $/ydA3
181,599.40 $
3
59,153 ftA2
0.26 $/ftA2
46,139.26 $
1
59,153 ftA2
0.13 $/ftA2
7,689.88 $
2
59,153 ftA2
0.53 $/ftA2
62,702.07 $
2
1 ft
59,153 ftA2
118,306 ftA3
4,382 ydA3
12.57 $/ydA3
55,077.92 $
1
2ft
59,153 ftA2
118,306 ftA3
4,382 ydA3
5.78 $/ydA3
25,326.20 $
51,455 ftA2
3ft
154,366 ftA3
5,717 ydA3
27.63 $/ydA3
157,968.01
3
51,455 ftA2
0.26 $/ftA2
40,135.19
1
51,455 ftA2
0.13$/ftA2
6,689.20
2
51,455 ftA2
0.53 $/ftA2
54,542.70
2
1 ft
51,455 ftA2
102,911 ftA3
3,812 ydA3
12.57 $/ydA3
47,910.67
1
2 ft
51,455 ftA2
102,911 ftA3
3,812 ydA3
5.78 $/ydA3
22,030.52
Leachate collection and removal system
Area required
Installed unit cost
Cost $
Leak detection system
Area required
Installed unit cost
Cost $
59,153 ftA2
3.39 $/ftA2
200,528.32 $
59,153 ftA2
3.39 $/ftA2
200,528.32 $
51,455 ftA2
3.39 $/ftA2
174,433.73
51,455 ftA2
3.39 $/ftA2
174,433.73
Waste and Fill Layer
Volume of fill required
Unit cost
Cost of flow/able fill $
74,426 ftA3
2,757 ydA3
5.78 $/ydA3
15,932.75 $
63,917 ftA3
2,367 ydA3
5.78 $/ydA3
13,682.89
Appendix G - Option C Monofill-Final.xls
G-4
-------
Labor & Materials
Top Liner
Without macroencapsulation
Area required for storage + liner slope
Cost of compacted clay
Clay thickness
Clay volume
Unit cost
Cost of compacted clay $
Geotextile support fabric
Layers required
Area required
Unit cost
Cost for geotextile support fabric $
Geotextile filter fabric
Layers required
Area required
Unit cost
Cost for geotextile filter fabric $
HOPE liners
Layers required
Area required
Unit cost
Cost for HOPE liner $
Gravel drainage layers
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted gravel $
Compacted fill soil
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted soil $
Compacted top soil
Layers required
Thickness of each layer
Area required
Volume required
Unit cost
Cost for compacted soil $
59,153 ftA2
1.5ft
88,729 ftA3
3,286 ydA3
27.63 $/ydA3
90,799.70
2
59,153 ftA2
0.26 $/ftA2
30,759.51
1
59,153 ftA2
0.13 $/ftA2
7,689.88
1
59,153 ftA2
0.53 $/ftA2
31,351.04
1
0.5ft
59,153 ftA2
29,576 ftA3
1,095 ydA3
12.57$/ydA3
13,769.48
1
3ft
59,153 ftA2
177,459 ftA3
6,573 ydA3
5.78 $/ydA3
37,989.31
1
1 ft
59,153 ftA2
59,153 ftA3
2,191 ydA3
1 7.68 $/ydA3
38,734.19
With macroencapsulation
51,455 ftA2
1.5ft
77,183 ftA3
2,859 ydA3
27.63 $/ydA3
$ 78,984.00
2
51,455 ftA2
0.26 $/ftA2
$ 26,756.80
1
51,455 ftA2
0.13$/ftA2
$ 6,689.20
1
51,455 ftA2
0.53 $/ftA2
$ 27,271.35
1
0.5ft
51,455 ftA2
25,728 ftA3
953 ydA3
12.57$/ydA3
$ 11,977.67
1
3ft
51,455 ftA2
154,366 ftA3
5,717 ydA3
5.78 $/ydA3
$ 33,045.79
1
1 ft
51,455 ftA2
51,455 ftA3
1,906 ydA3
1 7.68 $/ydA3
$ 33,693.74
Vegetation to stabilize topsoil
Area required
Unit cost
Cost $
59,153 ftA2
1.36 acres
1 743.40 $/acre
2,367.47
51,455 ftA2
1.18 acres
1 743.40 $/acre
$ 2,059.40
Groundwater Monitoring Wells
Clusters (three wells) required
Cost per cluster $
Cost $
4
24,167.48
96,669.92
$
$
4
24,167.48
96,669.92
Appendix G - Option C Monofill-Final.xls
G-5
-------
Direct O&M (filling)
Summary of Annual Direct O&M Costs (filling)
Staff
Groundwater Monitoring
Utilities
Fee
TOTAL
Without
macroencapsulation
$724,561
$4,752
$10,000
$110,897
$850,210
With
macroencapsu lation
$708,305
$4,752
$10,000
$108,459
$831,516
Staff
Operators
Maintenance Tech
Logistics/Shipping
Operations Supervisor
Administrative Assistant
Plant Manager
QA / Health & Safety Coordinator
Burdened Annual
Salary
$45,227
$66,162
$37,306
$73,664
$45,727
$133,022
$67,012
Qty
4
1
1
1
1
1
1
Without macroencapsulation
Annual
utilization
1.20
1.20
1.20
1.20
1.20
1.20
1.20
Totals:
Total
$217,089.60
$79,394.40
$44,767.20
$88,396.80
$54,872.40
$159,626.40
$80,414.40
With macroencapsulation
Annual
utilization
1.17
1.17
1.17
1.17
1.17
1.17
1.17
Total
$212,219
$77,613
$43,763
$86,414
$53,641
$156,045
$78,610
$724,561.20|
$708,305
Groundwater Monitoring
Number of groundwater monitoring wells
Samples per year from each well
Cost for sample analysis
Annual Cost
4
12
$99
$4,752
4
12
$99
$4,752
Shipments per year without macroencapsulation
Truck weight limit
Weight of one barrel loaded with treated mercury
Barrels per truck delivery
Flat bed trailer width
Flat bed trailer length
Area available on flat bed trailer
Area required by one barrel
Area required by barrels in one shipment
Barrels per year
Shipments per year
40,000 Ib
892 Ib
44 barrels
8ft
40ft
320 ftA2
2.2 ftA2
96 ftA2
13724
312
Shipments per year with macroencapsulation
Truck weight limit
Barrels per Arrow-Pak
Weight, one tube w/barrels of treated Hg (empty tube is 950 Ib)
Arrow-Pak tubes per truck delivery
Area required by one Arrow-Pak tube
Area required by tubes in one shipment
Area available on flat bed trailer
Tubes per year
Shipments per year
40,000 Ib
7
7194 Ib
5 tubes
23.3 ftA2
116 ftA2
320 ftA2
1525
305
Appendix G - Option C Monofill-Final.xls
G-6
-------
O&M (post-closure)
Summary of Post-Closure Costs
Leachate collection and removal system
Leak detection system
Ground water
Utilities
License and bonding fees
Fee
Contingency
Total 30-year Cost
Without macroencapsulation
$10,437
$19,135
$5,940
$30,000
$300,000
$54,827
$42,034
$462,372
With macroencapsulation
$10,437
$19,135
$5,940
$30,000
$300,000
$54,827
$42,034
$462,372
[Cost for one day of operator time for each inspection
$174|
Leachate collection and removal system
First five years
Monitoring per year
Cost per sample
Total cost
12
$174
$10,437
12
$174
$10,437
Leak detection system
First five years
Following twenty-five years
Monitoring per year
Cost per sample
Cost (first five years)
Monitoring per year
Cost per sample
Cost (following twenty-five years)
Total
12
$174
$10,437
2
$174
$8,698
$19,135
12
$174
$10,437
2
$174
$8,698
$19,135
Ground water monitoring
Samples per year
Cost per sample
Total cost
2
$99
$5,940
2
$99
$5,940
Appendix G - Option C Monofill-Final.xls
G-7
------- |