Potential Radon Emissions due to Biogas Generation at TENORM Land Disposal Sites

Abstract

Abstract Allowing disposal of technologically enhanced naturally occurring radioactive materials (TENORM) from petroleum exploration and production in non-hazardous waste landfills was proposed in a U.S. Deparment of Energy study. TENORM often contains radium that is a source of radon. Diffusion through soil and other cover materials is commonly regarded as the dominant radon transport process from land disposal units. Biogas generation in landfills may increase radon emissions relative to diffusion-dominated sites. A numerical gas flow and transport model was used to simulate potential radon emissions from radium-bearing TENORM in solid waste landfills and land disposal sites where TENORM is co-disposed with oily waste. The landfill scenarios considered the effect of landfill gas generation potential and rate, cover construction, TENORM disposal method, and gas control methodology on radon emissions. The co-disposal scenarios investigated the effect of biogas generation rate, organic carbon partitioning, and cover construction on radon emissions. Gas generation was found to significantly increase radon emissions from landfills. Depending on the nature of the gas management system, atmospheric radon concentrations could exceed background level both on-site and off-site. The effect of biogas generation on radon emissions from co-disposal sites was found to be strongly dependent on the hydrocarbon content of the waste. The results of this investigation provide guidance for selecting appropriate TENORM disposal options and for evaluating the potential environmental liabilities associated with the options.