Partitioning of mercury among solid, liquid and gas phases following anaerobic decomposition of a simulated solid waste

The purpose of this study was to determine the partitioning of Hg among sol id, liquid, and gas phases following anaerobic decomposition of a simulated solid waste. A simulated solid waste was spiked with Hg(NO3)(2), placed in anaerobic, leachbed reactors, and allowed to undergo anaerobic decompositi on. Methane yields, volatile fatty acid production, and pH indicated that t he reactors were performing as expected for anaerobic decomposition in a le achbed reactor operated in batch mode. After anaerobic digestion, the bulk of the Hg that was added to the reactors was recovered in the solid waste. Essentially no Hg was found in the leachate. Some Hg volatilized during ana erobic decomposition. The percentage of Hg volatilized ranged from about 2 to 48% of the Hg added, with the higher percentages being associated with t he lower Hg levels. The presence of Hg in tubing that connected the reactor s to carbon traps indicated that organic forms of Hg may have volatilized, most likely dimethylmercury. These results indicate that landfills are a po tential source of atmospheric Hg pollution.