46 Paper No. 99-0805 TRANSPORTATION RESEARCH RECORD 1661 In the past, asphalt extractions were performed using toxic solvents; alternative, less polluting methods have been developed that can replace the traditional solvent extraction method. Accordingly, five potential asphalt extraction methods were compared for the Nebraska Department of Roads Bituminous Laboratory: solvent extraction using trichloro- ethylene (TCE), solvent extraction using an alternative solvent, solvent extraction using TCE and a solvent recovering reclaimer, ignition oven, and an ignition oven and solvent combination. To compare the total cost of each option, the direct capital costs, operating and maintenance costs, as well as the hidden environmental, health, and safety costs were con- sidered. Because the hidden costs can be difficult to quantify, a total cost assessment approach was used. To represent the uncertainties in the cost and design data, fuzzy set theory was used. A traditional economic analy- sis, including only the capital, and operating and maintenance costs, found that the three least-cost options were within the range of uncer- tainty of the analysis; these three options were the ignition oven (most environmentally friendly option), ignition oven with solvents, and sol- vent reclaimer. However, when the hidden costs related to the environ- mental, health, and safety aspects for an asphalt extraction procedure were incorporated into the cost analysis, the cost comparison changed significantly; the most environmentally friendly option, ignition oven, was shown to be by far the least-cost option. Accordingly, the quantifi- cation of environmental, health, and safety costs that are difficult to assess is very important when evaluating environmentally friendly processes. For many years, asphalt extraction has been performed using toxic solvents [e.g., trichloroethylene (TCE) and methylene chloride]. For example, the Nebraska Department of Roads (NDOR) Bituminous Laboratory currently uses TCE to perform the solvent extraction pro- cedure, using Method A (AASHTO T164-86 and ASTM D2172-95). The bituminous laboratory employs four staff who perform approx- imately 1,000 asphalt extractions per year. Consequently, there is a need to investigate other options to replace the traditional solvent extraction method. To compare the economics of alternative options to the solvent extraction method, the full costs of using toxic solvents not captured by traditional cost assessments must be considered. Frequently, traditional cost analyses consider only the capital pur- chasing, and the operating and maintenance costs associated with a process. However, many business costs (e.g., electricity, waste dis- posal, regulatory compliance, worker compensation, long-term lia- bilities) are often lumped into general overhead and not allocated to the specific processes in which those costs are incurred; these costs are referred to as hidden costs. A cost analysis that includes tradi- tional costs and hidden costs is a total cost assessment (TCA). The goal of this research was to develop a rational method for compar- ing different asphalt extraction procedures while taking into account capital, and operating and maintenance costs, as well as other hid- den costs associated with each different asphalt extraction option. There is considerable uncertainty in the true value of some of these hidden costs; therefore, uncertainty modeling using fuzzy set theory was used. New methods of asphalt extraction (e.g., alternative solvent or igni- tion oven) are attractive alternatives because they often incorporate the ideals of pollution prevention. Pollution prevention is the concept of eliminating waste at the source, in this case by replacing toxic sol- vents with nontoxic alternatives or by eliminating the use of solvents. The ideals of pollution prevention were integrated into determin- ing alternatives for the asphalt extraction procedure. Because other asphalt extraction methods now exist, NDOR worked with the Uni- versity of Nebraska-Lincoln to investigate other options that may pro- vide a safer working environment for their employees and reduce costs. Accordingly, the economics of five different asphalt extraction options were compared in this research. The current extraction procedure used by NDOR, which uses TCE as the solvent to extract the bitumen from asphalt samples, was the first asphalt extraction option investigated. The second method fol- lowed NDOR’s current extraction procedure, except the TCE and bitumen waste solution (from the end of the process) was placed into a solvent reclaimer to recover the TCE. The reclaimed TCE can be reused, thus reducing the TCE purchasing and disposal requirements. The third option was the use of an alternative solvent that is nontoxic (NEUGENIC 4175 from Rochester Midland was considered for this study). The alternative solvent could be used as a drop-in replacement (i.e., no changes to the current procedure) for TCE. The fourth option was the use of an ignition oven (two are required for NDOR’s lab). Instead of using a solvent, the ignition oven ignites and burns off the bitumen, converting the bitumen into carbon dioxide and water. The final option was the combination of an ignition oven and NDOR’s current extraction procedure. This option was included in the analy- sis to allow the lab to purchase one ignition oven and use the current solvent procedure to test samples during the summer months when it receives the peak number of samples and when a single oven would not provide sufficient testing capacity. For all five asphalt extraction options the economic and process data were uncertain and imprecise and therefore difficult to quantify. Some of the direct costs (e.g., waste disposal, new equipment) and the hidden costs (e.g., regulatory costs, potential liabilities) were imprecise. To model the imprecision in the data and costs, fuzzy set theory was used. To account for all costs associated with each asphalt extraction method, a TCA approach was used. The TCA approach allows for the proper identification of costs for each asphalt extrac- Comparison of Asphalt Extraction Procedures Implications of Hidden Environmental and Liability Costs MICHAEL L. BEHRENS, BRUCE I. DVORAK, AND WAYNE E. WOLDT M. L. Behrens, Jacobson Helgoth Consultants, 1033 O Street, Suite 546, Lin- coln, NE 68508-3621. B. I. Dvorak, Department of Civil Engineering, Uni- versity of Nebraska, W348 Nebraska Hall, Lincoln, NE 68588-0531. W. E. Woldt, Department of Biological Systems Engineering, University of Nebraska, 253 LWC, Lincoln, NE 68583-0726.