SUMMARYRadioactive, acidic waste stored at the Idaho Nuclear Technology and Engineering Center (INTEC) have been previously converted into a dry, granular solid at the New Waste Calcining Facility (NWCF). As an alternative to calcination, direct vitrification of the waste, as well as the calcined solids in an Idaho Waste Vitrification Facility (IWVF) is being considered to prepare the waste for final disposal in a federal repository. The remaining waste to be processed is Sodium-Bearing Waste (SBW).Off-gas monitoring during NWCF operations have indicated that future mercury emissions may exceed the proposed Maximum Achievable Control Technology (MACT) limit of 130 ug/dscm (micrograms/dry standard cubic meter) @ 7% O 2 for existing Hazardous Waste Combustors (HWC) if modifications are not made. Carbon monoxide and hydrocarbon emissions may also exceed the MACT limits. Off-gas models have predicted that mercury levels in the off-gas from SBW vitrification will exceed the proposed MACT limit of 45 ug/dscm @ 7% O 2 for new HWCs.Options to enable the NWCF to meet the MACT limits included construction of a MACT Compliance Facility (MCF), including a Noxidizer for NO x removal, or upgrading the NWCF by installing a multi-sieved wet scrubber for mercury removal. Both options included continuous removal of mercury from the scrubber blowdown by electrochemical reduction, followed by an activated carbon polishing bed. In the NWCF upgrade option, the carbon bed was also to be used for removal of products of incomplete combustion. Thus, studies of the mercury removal efficiency of activated carbon were initiated to support the above-mentioned options. These studies indicated that Mersorb , a sulfur-impregnated carbon manufactured by Nucon International, was highly effective (>99% removal) in removing both elemental ( The test results obtained indicated that Mersorb may have potential for removing a sufficient amount of mercury from SBW vitrification off-gas to enable compliance with the MACT limit. No negative short-term effects of test gas components on mercury removal efficiency were apparent. Future recommended studies include small bed (1cm. diameter) tests to determine long-term effects of SBW vitrification off-gas components on HgCl 2 and Hg o removal efficiency. Also recommended are breakthrough capacity and bed size optimization studies with a larger test bed to determine maximum removal efficiency, and obtain scale-up data, which can be used to design a carbon adsorption bed for a pilot-scale melter.v