Engineering-scale test 4: In situ vitrification of toxic metals and volatile organics buried in INEL soils

An engineering-scale in situ vitrification (ISV) test was conducted on soils containing a mixture of buried waste materials expected to be present at the Idaho National Engineering Laboratory (INEL) subsurface disposal area (SDA). The test was part of a Pacific Northwest Laboratory (PNL) program to assist INEL in treatability studies of the potential application of ISV to mixed transuranic wastes at the INEL SDA. The purpose of this test was to determine the feasibility of using ISV to vitrify soils containing a mixture of buried hazardous heavy metals (Ag, As, Ba, Cd, Cr, Hg, Pb, Se), with stainless and carbon steels, nonhazardous combustibles, and organics in the form of cemented sludge/grease mixtures. Specific objectives included determining the destruction and removal efficiency of hazardous volatile organics, determining the distribution of hazardous heavy metals between vitrified components, soils, and the ISV off-gas system, determining the leachability of the vitrified product, and evaluating electrode coatings. Actual site soil from INEL was used in the test and a basalt block was placed at a depth of 66 cm (26 in.) below the soil surface. The basalt was included to simulate basalt layers below the SDA and to evaluate bonding of the glass to basalt and possible contaminant transport into the basalt. 5 refs., 11 figs., 13 tabs