DEPLOYMENT OF CHEMICAL EXTRACTION SOIL TREATMENT ON URANIUM CONTAMINATED SOIL ABSTRACT Jeffrey P. Kulpa Earthline Technologies Ashtabula, Ohio (440) 993-2804 John E. Hughes Earthline Technologies Ashtabula, Ohio (440) 993-1968 One of the significant contributors to the cost of completing D&D activities at most Department of Energy (DOE) sites is the remediation of contaminated soil. The traditional approach of excavation, packaging, transportation, and burial at an approved disposal site can be the major contributor to overall project cost. At the Ashtabula Environmental Management Project (AEMP) in Ashtabula, Ohio, soil remediation in the approved project baseline accounted for over $45 Million of a total project cost of $150 Million. To reduce project costs and shorten the project schedule, Earthline Technologies has designed, built and is operating a chemical extraction soil washing facility. The facility has successfully processed over 14,000 tons of contaminated soil. The Earthline soil washing initiative has progressed from bench scale testing to establish the viability of the process, pilot plant operations to refine engineering approaches, through final design and construction of a first of its kind chemical extraction soil washing plant. The Earthline soil washing plant uses a 0.2M carbonate solution that is heated to approximately 115 o F and contacts the soil for approximately 90 minutes to leach the uranium from the soil. The process has operated as designed and has resulted in contaminant removal efficiencies of approximately 85% and volume reductions in excess of 90%. The chemical extraction technology provides a remediation approach for the 60,000 tons of uranium contaminated soil at the AEMP in Ashtabula, Ohio. The soil washing approach provides projected savings of approximately $300 per ton when compared to ship and bury costs. This paper describes the process flow for the carbonate extraction plant and provides a description of monitoring conducted to ensure that clean soil meets regulatory requirements to be used as clean back fill in restored areas. In addition, lessons learned from the first campaign of soil washing are discussed. Finally, plant improvements and activities to allow treatment of soil contaminated with Technetium-99 and Trichloroethylene (TCE) are briefly discussed.
INTRODUCTION Earthline Technologies has developed a remediation approach for the DOE s Ashtabula Environmental Management Project (AEMP) for removing uranium contamination from soil. The treatment approach was tested and proven effective in bench scale and pilot plant operations. Soil treatment using carbonate extraction reduces the volume of contaminated material requiring off-site disposal, which has the positive effect of lowering total project costs associated with soil remediation from $45 Million for ship and bury to $25 Million for treatment. This paper describes the operations of this first of a kind, 10 ton per hour, continuous flow, chemical extraction soil treatment production plant. Background The RMI Titanium Company operated the RMI Extrusion Site in Ashtabula, Ohio from 1962 through 1990 as part of the U.S. Department of Energy (DOE) weapons production program. Depleted, normal, and slightly enriched (up to 2.1% weight percent U-235) was extruded as part of the DOE production reactor fuels manufacturing process. RMI also extruded depleted and natural uranium under a Nuclear Regulatory Commission (NRC) license and extruded nonradioactive metals (primarily copper based) for the commercial sector. However, the majority of material processed at the facility was for DOE. All extrusion operations at the RMI Extrusion Site ceased on October 31, 1990. In 1990, the NRC identified the RMI Extrusion Site for accelerated cleanup under the Site Decommissioning Management Plan (SDMP). DOE accepted financial responsibility for the cleanup based on previous site operations, which supported the DOE mission. Since 1990, the site has performed equipment and legacy waste removal, selected building demolition, soil remediation, and planning/permitting in support of groundwater remediation. The remediation effort is governed by guidance and regulations promulgated by the NRC for site decommissioning and license termination. In addition, the presence of chemical constituents (TCE) in groundwater has led to involvement by the U.S. and Ohio Environmental Protection Agencies (EPA) in remediation decisions involving a Corrective Action Management Unit (CAMU). Earthline Technologies is the prime contractor to DOE for completion of site decommissioning. The DOE Ashtabula Environmental Management Project Office (AEMP) provides day to day oversight of the remediation effort. The DOE approved project baseline for the decommissioning project is approximately $150 Million and the project is scheduled to complete in Fiscal Year 2006. The site consists of 25 buildings on 7 acres of the 32 acre site and is located in Northeastern Ohio about 50 kilometers north of Cleveland and approximately 1.5 kilometers south of Lake Erie. The area immediately adjacent to the site is sparsely populated. The majority of the site and surrounding area is relatively flat with the maximum elevation variation being 4 feet. The site is on the Lake Erie Flood Plain geographical feature, which formed in the latter part of the Wisconsin Age.
Description of Site Soil Contamination The primary practice that contributed to soil contamination at the RMI Site was uranium extrusion manufacturing. Particulate uranium was generated in the extrusion building during operation of the main 3,850 ton extrusion press and during operation of other machining equipment. Hoods and fans were used to exhaust the fine uranium dusts and fumes outside the buildings. Particulate deposition from the exhaust system contaminated the surrounding soils with uranium. The soil at the site is predominantly clay (>80%) with a small sand fraction and some non-native gravel that was used for plant service roads. The uranium contamination at the site is generally stratified within shallow topsoils with highest activities found in the top 15 cm. of soil. Site characterization data indicates that in general, uranium activities fall below the treatment standard of 30 pci/gm at a depth of approximately 46 cm. Average uranium contamination levels in the AEMP soils are approximately 100 pci/gm. The total amount of soil contaminated with uranium at the AEMP is approximately 60,000 tons (1 ton = 907 kg). In addition to uranium contamination, the soil is also contaminated with Technetium-99 (Tc-99), a byproduct of uranium recycling. The cleanup levels established by the U.S. Nuclear regulatory commission are 30 pci/gm for total uranium and 65 pci/gm for Tc-99. The unity rule for contamination levels for free release of the soil also exists in that: (CU/30 pci/gm) + (CTc/65 pci/gm) must be <1 (Eq. 1) where CU is the concentration of total uranium in the soil in pci/gm CTc is the concentration of Tc-99 in the soil in pci/gm Tc-99 impacts approximately 10,000 tons of the total volume of soil. However, Tc-99 presents different technical challenges than uranium with respect to extraction chemistry. Earthline has developed a process modification, which allows for efficient extraction of the Tc-99 in the soil. This process will be used during the next campaign of soil washing. Project Overview In late 1996, Earthline conducted bench scale screening in order to assess the viability of soil washing as a treatment option for the remediation of the high clay content soils present in Ashtabula. This study found that the Ashtabula soils could be treated effectively using a 0.2 M sodium bicarbonate solution at a temperature of approximately 115 o F and a retention time of 1.5 hours. Treatability testing showed that chemical treatment using carbonate extraction achieved removal efficiencies of up to 90% and was effective in meeting the treatment standard of 30 pci/gm for most of the site soils. A cost estimate of soil washing using the chemical extraction approach indicated that significant cost savings could be realized for the AEMP by implementing soil washing as the soil remediation approach. Based on the results of the treatability study, a pilot plant was designed to process 2-ton batches of contaminated soil. The purpose of the pilot plant was to validate the results of the treatability
study and to optimize process design parameters. The pilot plant was operated on 38 batches in early 1998 to test various feed conditions. The results of pilot plant operations indicated that chemical extraction soil washing would result in contaminant removal efficiencies of approximately 82% and volume reductions of 95% (i.e., <5% residual waste requiring off-site disposal). A cost estimate of full production soil washing operations based on pilot plant results indicated that savings of over $300 per ton could be realized when compared to ship and bury. SOIL WASHING TECHNOLOGY DESCRIPTION This section will provide a brief overview of the 10 ton per hour carbonate extraction system which has been constructed by Earthline Technologies. A block diagram of the process is illustrated in Figure 1. In the chemical extraction process, uranium in the contaminated soil is converted into a watersoluble form and extracted from the soil. This process which uses a relatively mild concentration of sodium carbonate to form a carbonate complex with uranium, is approximately 85% to 95% effective depending on properties of the soil and source term of the uranium material contained in the soil. Processed soils however, do contain trace levels of water-soluble uranium. This is largely due to levels of water-soluble carbonate complexed uranium contained in the interstitial soil water and uranium sorbed on clay and silt soil particles due to ion exchange reactions. Earthline devoted substantial research, design, and modeling efforts to ensure that processed soil would not have a negative impact on the long term environmental quality. The results of these efforts are discussed in the uranium stabilization section of this paper. The Soil Washing Production Plant is designed to leach uranium from contaminated soil using a nominal 0.2 M sodium carbonate/sodium bicarbonate solution. Following extraction, the soil is dewatered and staged as clean soil. The clean, treated soil is returned to the site as clean backfill. As a result of this process, significant volume reduction is achieved which minimizes radioactive low level waste (LLW) material which has to be transported off-site and buried, and thus minimizes soil remediation costs. Soil from the Soil Staging Pad is processed through the Soil Washing Production Plant and after treatment it is conveyed outside to a covered Treated Soil Staging Pad. This pad is located on the south end of the Production Plant and functions as a staging area for the soil until it has been sampled, analyzed and field verified to meet the treatment standard. Following field verification of the treated soil, it is loaded using a front end loader onto a dumptruck and transported back to the excavated areas for staging, free release, and ultimately backfilling. The AEMP soil is planned to be processed in two campaigns. The first, Campaign 1, consists of soil from the outer site areas, which was excavated in 1998 through 2000. Campaign 1 consists of approximately 20,000 tons of soil. Campaign 2 consists of soil from areas close in and under the buildings. Campaign 2 will be completed as buildings are demolished and will consist of approximately 40,000 tons.
Untreated Soil Feed Hopper To Wet Screen Recycle Leachate Storage Tank Drum Scrubber Wet Screen <2mm Slurry Reactor Tanks (3) >2 inch Oversize 2 mm Oversize Clarifier Belt Filter Press Regeneration Tanks (3) Ion Exchange Columns (4) Barren Leachate Storage Tank Uranium Stabilization Evaporation Tanks Treated Soil Volume Reduction Evaporation Fig. 1: Soil Washing Process Simplified Flow Diagram Process Description Contaminated feed material is introduced into the plant using a front end loader to dump soil into the feed hopper. The feed hopper is equipped with the conveyor that passes the feed materials through a clod breaker to size reduce large chunks of soil. Soil falls through the clod breaker onto the primary Feed Conveyor which transports the feed material to the transfer conveyor. The transfer conveyor carries the feed material to the feed chute of the drum scrubber. At the drum scrubber water is introduced to the feed stream to the further reduce the size of the feed materials. The drum scrubber rotates on a slanted axis causing materials to travel toward the open end of the drum scrubber. A trommel screen in this portion of the drum scrubber allows materials that are less than 2 inches in size to drop onto the vibrating wet screen below. The fraction of the feed materials that is greater than 2 inches in size drops out the open end of the drum scrubber (this fraction usually consists of rocks, large organic matter, debris and balls of clay).
Material that falls to the wet screen is further segregated into greater and less than 2mm sizes. The fraction that is greater than 2mm is conveyed out of the plant for later processing, that which is 2mm or less in size is slurried and pumped to the Reactor Tanks. In Reactor Tank #1 the slurry is mixed with the sodium carbonate to produce a 0.2M solution. The solution is heated approximately 115 degrees F. The solution is gravity fed through the three reactor tanks and then into the Reactor Overflow Tank. From the Reactor Overflow Tank the leachate is pumped to the Lamella Clarifier. At the Lamella Clarifier, a polymer flocculant is added to the solution to allow the solids to settle out of solution. Solids are pumped to a belt filter press for de-watering, and liquids pump to the pregnant leachate tanks. Solids drop from the belt into the screw conveyor below. The screw conveyor transfers the processed soil into the mixing conveyor where stabilization and fertilization additives are mixed into the soil. The soil is then conveyed, via a radial stacker, to the clean soil pad. A pile on the clean soil pad consists of 80 to 100 tons, the amount processed in a usual day. The clean processed soil remains on the clean soil pad until analytical results confirm that the soil meets free release standards. Liquids from the Pregnant Leachate Tanks are pumped through a series of resin columns. The fluid passes through three of the four columns in a sequence designed to maximize resin efficiency and on line use. The first column that the fluid is introduced to will be the most heavily loaded with uranium. The second column will have the next highest loading value and the third the least uranium loading. When the resin in the first column is saturated with uranium it is taken off line and the fourth column is placed in service. The column that was second is now the first column in series and so on The column taken off line will be regenerated using a sodium chloride solution. Regeneration of each column requires approximately 24 hours. Leachate pumped from the resin columns enters the Barren Leachate Tank. The leachate is pumped to the Belt Filter Press spray nozzles, which clean the belts. The leachate is captured in sumps and is pumped to the Recycle Leachate Tank. From the Recycle Leachate Tank, the leachate is pumped to the Drum Scrubber and Wet Screen to assist in feed material size reduction and creating the initial slurry. EQUIPMENT DESCRIPTIONS Feed Hopper and Feed Ramp The Feed Hopper is a apron feeder designed to receive, hold, meter, and convey 10 tons per hour of soil into the Soil Washing Production Plant. The Feed Hopper is fabricated from carbon steel and has a nominal 60" wide variable speed, chain driven, pan feeder. Drum Scrubber A rotating, carbon steel, Drum Scrubber combines 10 tons per hour of soil from the Feed Hopper, and Recycle Leachate to create a 30 wt. % soil slurry. Undersize <2" material falls through the Drum Scrubber trommel screen, and oversize >2" material passes through the Drum
Scrubber trommel screen and leaves the unit as oversize. The Drum Scrubber has a working volume of 775 gallons; and nominal dimensions of 6' diameter x 16' long drum, and a 4' 3" diameter x 4' 3" long trommel screen located on the discharge end of the unit Wet Screen A nominal 3' wide x 7' long vibrating Wet Screen is provided to perform additional size fractionation of the <2" material which falls through the Drum Scrubber trommel screen. The wet screen is fitted with a 2 mm screen and spray nozzles to wash the fines from the oversize material. A modification to the plant prior to Campaign 2 will install a rock crusher which will crush the oversize material. The crushed oversize material will be recycled into the process thus further reducing the amount of material requiring off site disposal. Recycle Leachate Tank Recycle Leachate solution originates as Belt Filter Press filtrate and is pumped into the 7500 gallon Recycle Leachate Tank. The tank functions as a process water surge and buffer tank. The Recycle Leachate is pumped to the Wet Screen to wash the oversize, and it is pumped to the Slurry Pump Tank to dilute the Lamella Clarifier feed from 30% solids to 10% solids. Reactor Tank System The Reactor Tank System consists of 3 gravity feed, steam jacketed (2 of the 3 tanks), insulated, nominal 4000 gallon, carbon steel, atmospheric tanks in series with agitators to maintain the solids in suspension. The Reactor Tanks function as reaction and retention vessels to enable the 0.2 M sodium carbonate/sodium bicarbonate solution (ph=10) to solubilize the uranium at a 115 o F process temperature. After approximately 1-1/2 hours of retention time of the slurry in the Reactor Tanks, the leaching of uranium from the soil is completed. Lamella Clarifier System The 10 wt.% slurry from the Reactor Tank System is transferred to the Lamella Clarifier which functions, with the addition of coagulating and flocculating agents, to perform the initial dewatering of the slurry via gravity settling the solids out of solution. The Lamella Clarifier also functions to permit rinsing of the uranium from the solids leaving as a 35 wt.% slurry from the underflow of the Lamella Clarifier using Barren Leachate solution (i.e., Ion Exchange System effluent process water with a nominal 2 ppm uranium concentration). The overflow from the Lamella Clarifier gravity drains to the Pregnant Leachate Tanks. Pregnant Leachate Tanks Two 7500 gallon Pregnant Leachate Tanks are provided to collect the overflow from the Lamella Clarifier. Two tanks are provided to act as surge and buffer volume in the event of a Lamella Clarifier upset. The Pregnant Leachate is pumped out of the tanks to provide dilution water to the Lamella Clarifier Flocculant Make-up Unit, and pumped through a filter to remove residual solids > 150 um particle size and then fed to the Ion Exchange System.
Belt Filter Press and Soil Stabilization System The final dewatering of the slurry occurs within the Belt Filter Press. The soil sludge cake created by the Filter Press discharges into a screw conveyor and is transported outside and transferred onto the Soil Mixing Conveyor. The treated soil is stabilized by mixing it with chemical amendments (e.g., sulfuric acid to neutralize the soil ph to 7-8, and phosphate treatment to stabilize the residual soluble uranium). Following stabilization, the treated soil is conveyed onto the Treated Soil Staging Pad using the Radial Stacker Conveyor and staged as clean soil. Ion Exchange System The uranium from the Pregnant Leachate solution is recovered using an upflow Ion Exchange System. The Ion Exchange System consists of four 3,500 gallon pressure vessels. The vessels are designed and built in accordance with the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. At any one time, three of the vessels are in service, and the fourth is off-line being regenerated or in standby. The vessels contain a nominal 125 ft 3 strong base anionic resin, and are operated in series with the vessel with the highest uranium loading always operated as the lead vessel. Once the resin in the lead column is exhausted, the fourth regenerated column is brought on-line. The exhausted column is taken off-line, and it is regenerated to permit reuse. The regeneration process continues iteratively throughout the operation of the plant. Regeneration of the resin occurs in the Ion Exchange vessels using 2.0 M sodium chloride, and 0.1 M sodium bicarbonate solutions. Barren Leachate System One 7500 gallon Barren Leachate Tank is provided to collect the effluent of the Ion Exchange System and serve as a process water surge and buffer tank. Barren Leachate stored within this tank is fed to the Belt Filter Press to supply the belt spray wash water, fed to the Belt Filter Press Flocculant Make-up Unit to provide flocculant dliution water, and is fed to the Lamella Clarifier underflow in order to dilute the underflow from 35% to 10% solids. Boiler and Steam Distribution System A 150 boiler horsepower (BHP) or 5M btu/hr low pressure boiler is provided to supply low pressure <15 psig process steam to the Reactor Tank steam jackets, and intermittently to supply steam to the Caustic Wash Tank steam coil. Wastewater Evaporator System Process wastewater is minimized through recycling process water and regeneration solutions as much as possible. Wastewater which can not be recycled (i.e., 175 gallons per day) is sent to the Wastewater Treatment Plant (WWTP) and evaporated using a closed drum evaporator system. The system consists of 12 electrically heated Drum Dryers. The water vapor from the dryers is collected and condensed. Condensate from the condenser is collected within a sump and recycled back into the process. Residual solids from the drums are disposed of as LLW.
OPERATIONS The Earthline Soil Washing Facility is a 10 ton per hour continuous feed process. The plant is staffed by 8 operator technicians who perform the following operational tasks: Plant feed operations using a 2 cubic yard end loader. Feed operations include management of excavated soil staged for future operations. Operation of all required plant operating stations which include: plant feed; reactor tank systems, ion exchange and regeneration systems, clarifier and filter press systems, and stabilization systems. Chemical make-up operations. Minor plant operational maintenance and planned preventive maintenance. Clean soil product handling from the treated soil staging area to previously excavated areas for restoration of excavated areas. Plant operations are controlled by the plant operations supervisor who coordinates all operational activities. The plant is operated in single shift operations for five days a week. A typical week consisted of 10 hour operations for four days followed by one day for routine maintenance. This planned operating schedule allowed over 1,000 tons of soil to be processed in each month, which meets project requirements and DOE funding profiles. During the period from February through May 2000, an average production of 1,600 tons per month was achieved. The plant was very reliable. Despite being a first of its kind in the world, the plant achieved greater than 95% plant availability during Campaign 1 operations. CLEAN SOIL PRODUCT FREE RELEASE The RMI Decommissioning Project is governed by the Nuclear Regulatory Commission (NRC) through an approved Decommissioning Plan. Cleanup levels for soil are established at 30 pci/gm for total uranium and 65 pci/gm for Tc-99. Monitoring of activity levels in the soil is accomplished by several means. Real time monitoring during plant operations is accomplished through hourly X-Ray Fluorescence (XRF) sampling. XRF can provide total uranium results in less than 1 hour. During pilot plant operations, extensive statistical sampling was conducted to ensure accurate agreement between XRF and the regulatorily required Alpha Spectroscopy procedure. The samples taken for XRF are also used to provide a composite daily sample for all processed material. The composite sample is analyzed using alpha spectroscopy for uranium and gamma spectroscopy for Tc-99. All results are reviewed by the Radiation Safety Officer on a daily basis to ensure that license free release standards are satisfied. If the material does not meet standards, it is returned to the plant for processing. During Campaign 1, less than 1% of treated soil required re-processing. URANIUM STABILIZATION The clean free released soil product requires addition of several chemicals to ensure that there are no long term environmental impacts resulting from the use of the clean product which contain trace levels of water soluble uranium as backfill. The concern is that water soluble
carbonate complexed uranium contained in the interstitial soil will be released and impact surface water or groundwater. Earthline had extensive modeling performed by ARCADIS Geraghty & Miller (1), which led to the following conclusions: Surface erosion will not produce surface water uranium concentrations in local brooks that exceed the standard of 30 pci/l when the Kd value for the processed soil exceeds 800 L/Kg. Peak groundwater concentrations would not exceed 30 pci/l when the Kd value for processed soils exceeds 800 L/Kg. Kd is the Adsorptive Partitioning Coefficient and is defined as the ratio of soluble uranium in liquid phase over non-soluble uranium in the solids phase. Kd for untreated soil has a value of approximately 20 L/Kg. Earthline completed extensive laboratory testing to determine the correct formulations required to achieve the required Kd (2). The laboratory testing revealed that approximately 60 pounds of Triple Super Phosphate were required per ton soil processed to stabilize the uranium and remove its water soluble nature. In addition, 10 pounds of Sulfuric Acid were added to each ton of soil to restore the soil to neutral ph. These two additions had the impact of stabilizing the residual uranium in soil to protect the groundwater and of restoring the ability of the soil to support vegetation. Extensive re-vegetation experiments have been conducted to ensure that areas restored with clean soil product can be returned to vegetated conditions. The uranium stabilization efforts described above also have a positive effect on vegetation efforts resulting in a very acceptable growth medium. URANIUM REMOVAL EFFICIENCY Soil processing resulted in data regarding the initial uranium concentration and final treated uranium soil concentration. It was noted that the uranium removal efficiency was dependent on the initial feed concentration. Table I shows that removal efficiency increases with feed contamination levels. COST Table I: Uranium Removal Efficiency as a Function of Uranium Feed Concentration Average Feed Concentration Average Treated Concentration Observed Removal Efficiency 180 pci/gm 18 pci/gm 90% 100 pci/gm 18 pci/gm 82% 60pCi/gm 15 pci/gm 75% With the completion of processing 14,200 tons of contaminated soil, the cost of building and operating the soil washing plant is summarized to ensure that cost savings are resulting from operations as predicted.
Table II: Soil Plant Operating Cost Breakdown Cost Element Operations Labor cost for plant manager, shift supervisor, 8 operators, 3 treatability laboratory chemists, plus front end loader rental, dump truck rental, maintenance parts and labor. Capital Investment Cost - $4.3 Million construction cost plus $700K startup and permitting cost amortized over 60,000 tons. Sampling all required in process and confirmatory laboratory analysis both on site and off site to support plant operations. Residuals Management evaporation of residual water from ion exchange resin regeneration and off site disposal of residues. Utilities natural gas, electricity, and water Consumables Plant operating chemicals, replacement resin, and other consumables such as PPE and other supplies. Cost $169 per ton $83 per ton $16 per ton $18 per ton $6 per ton $17 per ton The total life cycle cost per ton of soil processed sums to $309. This compares very favorably with the total cost for shipment and disposal of $600 per ton. The estimated cost savings at the AEMP if 60,000 tons of soil are processed in lieu of off site shipment for burial is $17.5 Million. LESSONS LEARNED Several important lessons were learned as a result of processing the initial 14,200 tons of soil by Earthline Technologies. These include: The buildup of organic material in the leachate solution resulted in difficulty in precipitating uranium yellow cake from ion exchange regeneration solution. As a result, the process was modified to directly remove regeneration solution from the process and evaporate this liquid. This change had minimal impact on the volume of material requiring disposal and caused only a slight increase in the overall processing cost. The oversize fraction from drum scrubber operations was a substantially higher percentage of processed soil volume than estimated prior to operations. (20% versus 10%). The difference was attributed to the large amount of aggregate material brought on site to improve haul roads during site excavations. The oversize material will be processed by a rock crusher circuit, which will be installed during 2001.
CONCLUSIONS Earthline Technologies has constructed and operated a 10 ton per hour chemical extraction soil washing facility at a capital cost of approximately $4.0 Million. A cost comparison of traditional soil remediation through transportation and burial and soil washing reveals that at the AEMP, soil washing will save the DOE approximately $290 per ton of soil processed. The Earthline Soil Washing process is currently being modified and improved to include capabilities to: (1)Air strip TCE from soil in the reactor tanks. When permitted, this addition will allow Earthline to treat soil from the site Corrective Action Management Unit which is contaminated with uranium, TCE, and Tc-99, and, (2)Modify the plant process chemistry to add an oxidizing agent which will allow treatment of soil contaminated to high levels of Tc-99 thus minimizing the amount of Tc-99 soil requiring direct disposal. REFERENCE (1) Uranium Stabilization Determination, ARCADIS Geraghty & Miller, January 1999. (2) Groundwater Flow and Constituent Transport Modeling for Soil Washing at Ashtabula, Ohio, ARCADIS Geraghty & Miller, March 1999.