Andrew Drom
Technical Manager, Government Programs
Envirocare of Utah, Inc.

KayLin Loveland
DOE Program Manager
Envirocare of Utah, Inc.

In June, 1997, Envirocare of Utah, Inc. was contracted by the Kaiser-Hill Company, L.L.C., a DOE Integrating Management Contractor, to transport, treat and dispose of more than 13,000 cubic meters of radioactively and hazardously contaminated waste (Mixed Waste) from the Rocky Flats Environmental Technology Site (RFETS). The first phase of the project, to be completed by the end of fiscal year 1997, included the processing of 1,705 cubic meters of Saltcrete waste that had been stored at the RFETS for more than ten years.

Envirocare and the Kaiser-Hill team cooperated closely to develop an aggressive treatment and disposal schedule to meet FY97 Rocky Flats Cleanup Agreement (RFCA) milestones for the RFETS. This task included the development of a successful treatability formula, transportation of more than 1,500 cubic meters of waste from the RFETS in Colorado to Envirocare’s Clive, Utah facility, and the treatment and disposal of the 1,705 cubic meters of waste in less than eight weeks.

Saltcrete resulted from the evaporation of aqueous process waste waters and carried numerous EPA Hazardous Waste Codes. Many challenges were encountered and overcome during this process. First, Envirocare was tasked with developing a successful treatment formula during a limited amount of time, and developing a formula that minimized waste "growth", thus reducing disposal costs. Second, the Kaiser-Hill team and Envirocare loaded and transported the waste from RFETS to Envirocare’s site during an eight week window. This process included shipping up to five shipments of waste from a DOE facility in a given day. Third, Envirocare treated and disposed of the waste within one week of its arrival at the treatment and disposal facility. The "saltcrete" waste sent to Envirocare was produced by combining the dry salt waste with liquid waste concentrate and Portland cement and feeding the mixture into containers. Solidified waste forms required shredding and crushing as a part of treatment at Envirocare. Envirocare employed chemical fixation/stabilization technologies to reduce leachability of the hazardous constituents. Following treatment, waste material underwent verification sampling and analysis to insure that the waste material complied with Land Disposal Restrictions prior to disposal in Envirocare’s Mixed Waste disposal cell.

The Rocky Flats Environmental Technology Site (RFETS), located approximately fifteen miles northwest of Denver, Colorado, historic mission was the production of nuclear weapons components using various radioactive and hazardous materials, including plutonium, uranium and beryllium. After about forty years of production work, the site was listed on the Environmental Protection Agencies National Priorities List for cleanup. With the end of the cold war, the RFETS mission is now cleanup and closure.

Saltcrete is the result of wastewater processing and was the second largest mixed waste stream at RFETS requiring treatment and disposition during FY97. Most wastewater from RFETS production processes is accumulated in large feed tanks and then is treated by precipitation, filtration, evaporation, and drying to result in a matrix referred to as "salts". Original waste stream production was high in nitrates and sulfates, thus the reference to the dried material as "salts". However, current waste stream production has a significantly decreased concentration of inorganic compounds, even though the waste is still referred to as "salts". Saltcrete is formed when liquid evaporator concentrates are combined with the salts and Portland cement. The mixture is poured into cardboard and plywood containers to solidify into a monolith.

Because the process waste water contains hazardous waste Saltcrete is a mixed radioactive waste. Radionuclide contamination principally includes Americium, Plutonium, and Uranium. The waste carries Resource Conservation and Recovery Act (RCRA) Hazardous Codes F001, F002, F005, F006, F007, and F009. RCRA contaminants include specific volatile and semi-volatile organic compounds and metals. Beginning FY97, approximately 3,400 cubic meters of Saltcrete did not meet Land Disposal Restriction (LDR) treatment standards and required treatment prior to disposal. At the writing of this paper, all of the Saltcrete requiring treatment had been successfully treated and disposed.

In June, 1997 Kaiser-Hill Company, L.L.C., the DOE Integrating Management Contractor for RFETS, contracted with Envirocare of Utah, Inc. to transport, treat and dispose of more than 13,000 cubic meters of radioactively and hazardously contaminated mixed waste, including the Saltcrete waste stream. Shipment of Saltcrete began in July, 1997. The first phase of 1,705 cubic meters of the Saltcrete waste stream was successfully transported, treated and disposed in less than eight weeks; the second phase of 1,710 cubic meters and the last of the Saltcrete waste stream was completed in the first quarter of FY98 in the same amount of time.

The mutual goal between Envirocare and Kaiser-Hill was to meet the Rocky Flats Cleanup Agreement milestone for FY97. To meet this milestone, 1,575 cubic meters of LDR non-compliant Saltcrete waste had to be shipped from RFETS by September 30, 1997. After contract award yet prior to shipment to Envirocare, a successful formula had to be developed in time to meet the specified goals. In order to accomplish this, Kaiser-Hill had to generate an adequate number of samples for treatability formula and Envirocare had to find a means of expediting formula development so transportation could begin in July, 1997.

Benchscale treatability studies were conducted using five (5) ‘worst-case’ samples of the Saltcrete waste that were collected by Kaiser-Hill. Due to the variability of RCRA Hazardous Waste constituents across the waste population, more than one treatability sample was required. This sample selection was required to ensure that the formula developed would be sufficiently aggressive to stabilize the hazardous constituents known to be present. Formula development services were subcontracted by Envirocare to InSciTe (a subsidiary of Mountain States Analytical Laboratory, Inc.). Formula development is a series of iterations involving the application of various combinations of chemical reagents in an effort to immobilize hazardous constituents. In accordance with existing permit requirements, Envirocare submitted a copy of the Treatment Formula to the State of Utah, Division of Solid and Hazardous Waste. The State retains this report for its reference.

Kaiser-Hill was successful in expediting sample selection, collection and delivery to Envirocare for analysis. Envirocare utilized rush analytical services and an accelerated schedule resulting in the formula being developed in less than one month. Notification for shipment was provided to Kaiser-Hill immediately upon successful formula development.

Coordination between Envirocare and Kaiser-Hill became critical during the transportation phase of the project. Each organization had its respective duties in transporting the waste off-site. Envirocare was responsible for arranging transportation, determining load make-up, reviewing shipping paperwork, scheduling shipments with the site, and determining the shipping schedule. The Kaiser-Hill team was responsible for preparing shipping paperwork, loading transportation vehicles, and providing the necessary information needed to determine load make-up.

Issues requiring consideration included the RFETS accelerated work schedule (9 regular work days in a 14 day period), loading and preparing paperwork for up to five shipments a day, monitoring Special Nuclear Material (SNM) quantities arriving at Envirocare, and maintaining an adequate quantity of waste material to support a 24 hour per day treatment operation.

Envirocare subcontracted with Zhagrus Environmental, Inc. to manage transportation issues, review shipping paperwork, and provide on-site support and coordination to Kaiser-Hill at the RFETS. The Zhagrus role provided a full-time, dedicated link between Envirocare and Kaiser-Hill to facilitate communication and offer immediate problem-resolution. The on-site coordinator proved to be critical in accomplishing the goal of 1,575 cubic meters of waste shipped in less than eight weeks.

In order to provide the Envirocare facility with enough feed stock to maintain an around-the-clock treatment team and reduce as much as possible overtime accumulation at the RFETS, pre-loading of shipments was practiced. Using a pool of extra trailers, shipments were prepared and loaded 1-4 days in advance of the scheduled shipping date. This allowed Kaiser-Hill to maintain their accelerated work schedule and also allowed truck shipments to leave on the days scheduled for timely arrival at the treatment and disposal facility. Additionally, the practice of having shipments pre-loaded allowed shipments to continue if there was a temporary work stoppage at the RFETS, and maintain the waste arrivals at Envirocare.

Considerable coordination was also required to maintain Saltcrete shipments within Envirocare’s SNM limit. Within a matter of days, shipments arriving at Envirocare had to be treated and permanently disposed in accordance with license conditions to manage undisposed SNM inventory and allow inventory space for more shipments. Specific SNM gram loading of shipments and scheduling SNM quantities became an integral part of remaining within regulatory and license conditions and still keeping a steady stream of waste leaving Rocky Flats.

All shipments of saltcrete were shipped with a primary hazard of Class 9 and a secondary Marine Pollutant. Although the material was handled as radioactive while on site, the activity concentration did not meet the DOT definition for radioactive material. A pool of dedicated drivers, trailers and trucks were provided during the shipping campaign. Sufficient personnel and equipment combined with detailed scheduling allowed a driver to leave Rocky Flats, generally deliver a shipment to Envirocare within 24 hours, and return to Rocky Flats to make the trip again. This eliminated requalifying drivers for access to RFETS and created transportation cost efficiencies.

One of the lessons learned during this project was that closer is not always better. Due to the short haul distance between Rocky Flats and Envirocare, approximately 1,200 miles round trip, the impact of delays at either end created a direct impact on shipment and treatment schedules. The contracting of Zhagrus to resolve this type of transportation issue was successful in minimizing impact on both sites.

Upon the arrival and acceptance of the Saltcrete material at Envirocare’s Clive, Utah treatment and disposal facility, containers of the waste were moved from sampling and storage pads to the Stabilization Building for management. Within the facility, Saltcrete materials were removed from the shipping containers and processed using a high-torque, opposing rotor, hydraulic shredder. When wooden containers were utilized by the generator for shipment, the waste material and the associated shipping container were shredded and prepared for treatment.

The shredded materials were then loaded into a 3.5 yard mixer at a rate specified by the established treatment formula. Following waste loading to the mixer, requisite quantities of reagents were added based upon the waste weight contained therein. The mixer was then operated for a period of time necessary to ensure adequate uniformity of the contents. Treated waste was emptied from the mixer into designated containers for sampling, curing and storage.

Post treatment sampling was conducted to ensure compliance of the final waste form with applicable treatment standards. Upon the receipt, review and verification of requisite analytical results, a Land Disposal Certification was prepared by Envirocare compliance personnel for each treatment run (a treatment run is generally defined as that material which is treated during a 24-hour period of treatment operation). The waste was then moved to the mixed waste disposal cell for final disposal and placement.

Although the treatment process was not required to operate at maximum physical capacity, more than 200 tons of material were routinely treated per week. Thus, Envirocare and Kaiser-Hill were able to reach the goal of 1,575 cubic meters of waste treated before September 30, 1997. Pre-treatment tasks and the desire to process the waste within an eight week window prompted Envirocare to move to a 24 hour per day operation. This process rate and project completion was only possible as a result of the transportation coordination between Envirocare and Kaiser-Hill.

Saltcrete is a mixed low-level waste, so the treated material was placed in Envirocare’s mixed waste cell for permanent disposition. The mixed waste cell is engineered with a triple HDPE liner system. Collection layers between each liner provide leachate management and leak detection for the cell, while a foundation of engineered clay stabilizes the liner system. Once design capacity is reached in the cell, waste is entombed in a seven foot clay radon barrier, a rock filter zone, and a coarse rock erosion barrier.

After Saltcrete was treated, the material was placed in the cell in 12 inch "lifts" or layers and then compacted to meet license criteria. Following disposal, Envirocare completed required Disposal Certificates as treated waste materials demonstrated compliance with applicable treatment standards and were placed in the disposal cells. The purpose of such documentation is to certify that the waste received was treated and disposed of in accordance with requirements listed in 40 CFR 268.7. The Disposal Certificate is provided as a summary document certifying that the subject shipments have been received, treated, verified compliant with treatment standards and disposed in accordance with existing requirements.

The treatment formula was uniformly effective in the treatment of the Saltcrete wastes. No material failed to meet treatment standards following treatment. All material shipped was compliantly treated and disposed in accordance with applicable federal regulations and Envirocare’s existing permit and license conditions.

Extensive coordination between Envirocare and Kaiser-Hill was a necessary element in successfully meeting the RFCA milestones and laying the foundation for meeting future goals. This experience is a case study for the expeditious and efficient treatment and disposal of large, mixed waste streams.

For reference, the remainder of the Saltcrete waste stream requiring treatment, 1,710 meters, was treated and disposed in the first quarter of FY98 and represents the completion of the waste stream. This task was accomplished in a similar manner and in a slightly shorter amount of time, given the experience gained during the first campaign.

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