United States Office of Publication No
Environmental Protection Solid Waste and 9375 5-06a/FS
Agency Emergency Response May 1991
SEPA The Cost of
Remedial Action Model
Office of Emergency and Remedial Response
Hazardous Site Control Division (OS-220W) OSWER9375506aFS Quick Reference Fact Sheet
INTRODUCTION
The Cost of Remedial Action (CORA) model is a computerized expert advisor used to select
remedial actions for Superfund hazardous waste sitesand estimate their costs. It may also be used
jfor RCRA corrective actions. The model is used for both current site-specific estimates, and for
program budgeting and planning.
The expert system, with its technical information and regulatory interpretations, interacts with
the user to guide in the selection of a remedy and to recommend a range of remedial action
technologies at a specific site. The cost system is used to develop cost estimates for the remedial
action scenario. The system provides order-of-magnitudeesumates for both capital and annual
O&M costs. The user must manually extrapolate these costs to determine total present and future
worth. The model is not currently designed to develop multiyear groundwater treatment
scenarios. Both the expert system and the cost system have been validated, and the model has
gained widespread use since its first release in 1987. Version 3.0 was released in May 1990.
This short sheet describes the following aspects of the CORA model:
• Development
• Tesung
Structure and function
• Applications.
Finally, the short sheet provides additional sources of information on the CORA model.
DEVELOPMENT OF THE CORA MODEL
The Superfund program requires accurate costestimates to managecurrent activities and develop budgets. In order to improve
the accuracy and objectivity of cost estimates, EPA conducted a study in 1983 to quantitatively define pricing factors for
remedial actions. A modeling approach was selected to develop pricing factors because of limited historical construction cost
information. Informauon used todeveloptheseearlycostmodelsincludeddataaboutconditionsatasampleof Superfund sites,
categorizations of site types, and guidance criteria for selecting remedies. This information was aggregated to obtain budget
pricing factors.
In 1985, EPA attempted to dis-aggregate early modeling results to obtain site-specific estimates. The variability of these
estimates confirmed the need for different modeling tools to determine accurate site-specific costs. In addition, EPA needed
a method to estimate remedial action costs in the pre-feasibility stage of analysis. The CORA model was developed in response
to these needs, and is used to select remedial action technologies and estimate Superfund costs on a site-specific basis.
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TESTING OF THE CORA MODEL
In order 10 confirm the accuracy of the CORA model, a validation exercise was performed by an independent consultant The
methodology employed by the study included examining the technology being implemented at each site, loading this data into
the CORA model, and comparing CORA estimates with actual costs (either bid or construction). In May of 1987, the model
was used to examine cost estimates for 12 sites The twelve sites were either in final design, had bids established, or were in
construction. Results of the analysis showed nine of the 12 were in the range of -30% to +50% of the CORA projections.
Modifications were made to the model and the results obtained in June of 1988 showed all 12 sites to be within range.
The consultant also conducted a subjective evaluation of the expert system of the model. This aspect of the validation exercise
sought to determine whether the CORA model recommendations conformed with good hazardous waste engineering practice,
and were reasonable solutions from an engineering perspecuve. Results showed the model to be successful in meeting both
criteria.
In a separate validation study conducted in 1990, the Department of Energy reviewed 25 RODs against the recommendations
generated by the CORA model on these 25 sites. Results of this comparison revealed that 97% of the CORA model
recommendations appeared as ROD alternatives.
The CORA model includes two independent subsystems: an expert system and a cost system. The expert system uses site
information generally accessible at the remedial investigation stage to recommend a range of remedial response actions from
among 42 different technologies (see table). The cost system is used todevelop estimates for the technologies selected, or may
be used to independently assess remedy recommendations from other sources. The following subsections describe the expert
system and the cost system more fully.
STRUCTURE AND FUNCTION OF THE CORA MODEL
CORA SYSTEM COMPONENT DETAILS
Technology Cost Modules
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Containment
Technologies:
Treatment
Technologies:
Disposal
Technologies:
Drum Removal
Soil Excavauon
Sediment Dredging
Pumping Contained Wastes
Groundwater Extraction
Active Landfill Gas Collection
Removal Technologies:
Soil Cap
Asphalt Cap
Multilayered RCRA Cap
Surface Controls
Slurry Wall
Air Stripping
Vapor Phase Carbon
Activated Carbon
Metals Precipitation
Activated Sludge
Soil Vapor Extraction
Soil Flushing
PJome Carbon Units
Offsite RCRA Treatment
Offsite RCRA Incineration
Onsite Incineration
Solidification
InSitu Biodegredation
Ion Exchange
Pressure Filtration
Flaring
Soil Slurry Bioreactor
Insitu Stabilizauon
Offsite RCRA Landfill
Onsite RCRA Landfill
Below Grade
Above Grade
Offsite Solid Waste Landfill
Discharge to POTW
Discharge to Surface Water
Water Reinjection
Water Infiltration -
Miscellaneous
Technologies:
Transportation
Municipal Water Supply
Groundwater Monitoring
Access Restrictions
Health and Safety
Site Preparation
Site Administration
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Expert System
The expertsystem contains the data that enables
the CORA model to evaluate the information
provided by the user. The user defines the site
by responding to system-selected questions for
waste types within a contaminated area of the
site. The expert system analyzes the site based
on user responses by focusing on up to 13
different types of waste matrices ranging from
contaminated soils to bayous, (o drums, to
buildings, and offers recommendations to
remedy the site. The CORA expert system's
knowledge bases have approximately 670
decision rules to apply the 42 available
technologies. The decision rules incorporate
technology-specific engineering expertise,
statute interpretations, and policy issues. The
user can change responses to questions posed
by the system, but cannot alter the decision
rules. The system provides paper output of
questions and responses to questions for future
use. Thus, the system enables the user to
perform sensitivity analyses by exploring
alternative outcomes based on different site
mformauon.
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A:
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Cost System
The CORA cost system is used to develop
order-of-magnitude cost estimates (-30% to
+50%) for sites after the response action
scenanosare developed, using theexpert system
or other sources. The CORA cost system
organizes cost estimates by site, operable unit,
scenario, and technology. The system and the
user interact to complete this information for a
site previously entered into the data base or for
a new site. The CORA cost system calculates
capital and first-year operation and maintenance
(O&M) cost estimates for each technology
selected. The user may save outputs to a data
base for subsequent analysis. In addition, the
CORA model generates a total summary report
for a site or operable unit for both capital and
O&Mcosts. Thesummary report includes costs
incurred by construction and operation of
individual unit processes and operauons, costs
for items such as site preparation and
administration, startup, permuting and legal
services, permit and insurance renewal, services
during construction, and bid and scope
contingencies.
st —
p Summary Report
• Capital Costs
• O&M Costs
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Hardware Requirements
The COR A model requires the following computer hardware
specifications.
• IBM compatible PC
MS-DOS environment
• 640K RAM
• 3 MB of hard disk space.
The CORA model is a stand-alone appl icaiion, not designed
for LAN use
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PRESENT AND FUTURE APPLICATIONS OF THE CORA MODEL
The CORA model is a powerful tool that saves lime and increases the user's awareness of the scoping process, policy issues,
technology costs, and design factors when selecting remediation schemes. Users have reported that, in particular, the expert
system increases awareness of regulatory requirements and restrictions. The model also familiarizes them with basic design
elements and individual technology costs. The CORA model has been used for several purposes since it was developed, tested,
and approved. The CORA model was used to make cost estimates for 97 Superfund sites likely to be FY 1989 remedial action
candidates. The results of the CORA expert system and costsystem runs were combined with other information to develop EPA's
FY 1989 budget. The model has subsequently been used to develop costs for components of FY 1991 and 1992 budgets. CORA
model data has helped EPA shape the selection of remedies under SARA.
The CORA model was applied to Navy installation restoration program sites to estimate Defense Environmental Restoration Act
funding for FY 1989,1990, and 1991. In addition, the Department of Defense uses the CORA model to develop remedial ac-
tion strategies and estimate their total remediation costs.
APPLICATIONS OF THE CORA MODEL
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User:
EPA
Purpose:
• Develop Superfund remediation budgets
• Perform initial site-specific remediation scoping
Benefits:
• Saves time -- 1-3
hours to scope and
cost a remedial action
scenario vs. 20-60
hours without the
model
Other Federal
Agencies
• Estimate ouiyear and total programmatic
remediation budgets
Pnvaie Industry
• Anticipate cost effects for Regulatory Impact
Analyses of new environmental regulauons
• Increases users'
awareness of
scoping, policies,
regulations, design
factors, and
technology costs J
States
• Estimate site-specific remediation budgeting and scoping
All of the
\. Above
• Screen, scope, and budget for technology of RCRA
Corrective Actions and closures
As the model is upgraded, new versions will become available. The newest version was released in May 1990 and includes sev-
eral new technologies, new cost algorithms, and new market prices for offsiie technologies.
TO OBTAIN THE CORA MODEL OR MORE INFORMATION
TheCORA model may beobtainedfromEPAfor$280,thecostofreproductionandsupport. TheCORA model package consists
of 8 diskettes,acomprehensiveuser'smanual.andonehouroftelephoneinformauonand assistance. Theuser'smanualcontains
required information about remedial technologies,cost assumptions, design ranges, technology uses, and schemaucs for the tech-
nologies. The following publication provides additional detail on the CORA model:
"The Cost of Remedial Acuons (CORA) Model: Overview and Applications," Richard K. Biggs, Kevin Klink, Jac-
queline Crenca, submitted for proceedings of HAZMACON 89, Santa Clara, California, April 1989.
Information may be obtained through the following:
The CORA Hotline - (703) 478-3566, to obtain the model and technical assistance, demonstrations,
training seminars, and CORA costing services
• The RCRA/Superfund Hotline - (703) 920-9810 or (800) 424-9346, for program information.
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