Offgas emissions from the plasma hearth process

The Department of Energy is currently evaluating SAIC's Plasma Hearth Process (PHP) for use as a new method of treating mixtures of radioactive and hazardous wastes. The PHP has been specifically designed for the treatment of both low-level and transuranic mixed waste. These mixed wastes range in composition from non-combustible inorganic sludge wastes to highly combustible plastic and organic sludge wastes. The unique aspect of the PHP technology is its ability to treat this wide range of materials even when combined as a poorly characterized heterogeneous mixture. The PHP uses a plasma-are torch to volatilize the organic components of the waste and vitrify residual inert materials. Hazardous organic constituents are destroyed in a secondary combustion chamber. Offgas from the process is thoroughly cleaned by state-of-the-art air pollution control equipment. This paper describes the results of the ''proof-of-principle'' testing of this technology and focuses on the results of the analysis of the offgas emissions. The results demonstrate that the PHP completely destroys organic material; that the PHP offgas emissions are readily controlled by state-of-the-art air pollution control equipment; and that the vitrified residual's leach characteristics are comparable to glass formulated for stabilization of high-level radioactive waste.