Destraction procedure

A two-step destraction procedure was developed to maximize the amount o T102 residuum brought overhead. In the first step, toluene is used in a manner similar to conventional supercritical extraction to produce a nearly ash-free material for subsequent fractionation. This first step is called the non-reflux mode because the column of the FDV is maintained at the same temperature as the extraction section. In the second step, called the reflux mode, the column and finger are heated to a higher temperature than the extraction section, which causes the density of the fluid to decrease as it travels up the column and thus promotes reflux of the less-soluble components. These two steps are described below. 

The routine monitoring of every hazardous constituent of the effluent gases of operating incinerators is not now possible. EPA has established procedures to characterize incinerator performance in terms of the destruction of selected components of the anticipated waste stream. These compounds, labeled principal organic hazardous components (POHCs), are currently ranked on the basis of their difficulty of incineration and their concentration in the anticipated waste stream. The destraction efficiency is expressed in terms of elimination of the test species, with greater than 99.99 percent removal typically judged acceptable provided that toxic by-products are not generated in the process. 

The effectiveness of incineration has most commonly been estimated from the heating value of the fuel, a parameter that has little to do with the rate or mechanism of destraction. Alternative ways to assess the effectiveness of incineration destraction of various constituents of a hazardous waste stream have been proposed, such as assessment methods based on the kinetics of thermal decomposition of the constituents or on the susceptibility of individual constituents to free-radical attack. Laboratory studies of waste incineration have demonstrated that no single ranking procedure is appropriate for all incinerator conditions. For example, acceptably low levels of some test compounds, such as methylene chloride, have proved difficult to achieve because these compounds are formed in the flame from other chemical species. 

Buesseler KO, Cochran JK, Bacon MP, Livingston HD, Casso SA, Hirschbeig DJ, Hartman, MC, Fleer, AP (1992a) Determination of thorium isotopes in seawater by non-destractive and radiochemical procedures. Deep-Sea Res 139 1103-1114... 

An administrative directive issued by the Director-General shall establish handling procedures for the Secretariat to ensure the secure disposal and destraction of material containing confidential information. These procedures shall cover ... 

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