The International Information Center for Geotechnical Engineers

Vitrification

Field Setup 

The vitrification process, when properly designed and executed, produces a product, which is highly stable and leach resistant. Though still at its early development stage, feasibility of various kinds of vitrification process has been examined in laboratory. After demonstrating success of process in the lab and in pilot scale, the field examination and setup could be developed, in which chemical and physical fundamental process firstly have to be conducted. Actually, it has been used more and more in the field.

  • Fundamental Processes

In general, vitrification treatment includes chemical incorporation and physical encapsulation of contaminants via pyrolysis or combustion, and volatilization of contaminants followed by their removal in the off-gas treatment system (USEPA, 1992a).

Chemical immobilization is achieved when contaminants are chemically bonded into the waste glass product. This is achieved primarily for metals and other inorganic contaminant.

Physical immobilization of contaminants is achieved through encapsulation of the contaminant in the waste glass product. This is the primary method for the remediation of heavy metal contaminants and the nonmetallic inorganic contaminants.

Thermal and chemical processes are the primary means of remediating organic contaminants and volatile inorganic contaminants when using a vitrification process. These processes include pyrolysis, combustion, and volatilization (USEPA, 1992a).

Organic contaminants that are vaporized but not thermally decomposed in the melt are remediated either through combustion or are removed in the off-gas treatment system. Metals, such as mercury, after being volatized during the vitrification process must also be treated via removal in the off-gas treatment system (USEPA, 1995b).

  • General Design Approach

There are three primary processes for general vitrification design: Treatability testing/bench-scale testing, engineering-scale testing, and pilot- and large-scale testing. The treatability testing is to demonstrate the applicability of technology to the specific soil/waste combinations at the site. The purpose for pilot-scale testing is to confirm that bench-scale testing results will be applicable on a larger scale. Engineering-scale testing is one of the primary developmental tools for ISV. It can test new concepts at a reduced cost while maintaining a high level of confidence in its predictive capabilities for larger-scale operations (USEPA, 1992a).

Figure 7. Field Set-up Design Process

 

 

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