Waste treatment offers a special challenge for long term disposal of residues, the requirement is generally driven by local regulation. Low operating cost rather than profit is the primary motive. The main focus in commercial installations has centered around vitrification of incinerator ash from municipal solid waste (MSW), primarily in Japan which suffers from a high population and small usable land mass. Where MSW ash, both bottom (hearth) and fly, were formerly landfilled, legislation now demands discontinuance of this practice due to concern over secondary pollution from Cd, Pb, Cr and Hg as well as dioxins which may reside in the ash. Commercial systems with power ratings from 600 kW to 3000 kW, utilizing plasma torches with transferred or non transferred are available.

In fact, current thinking indicates a greater concern for the hazardous nature of fly ash rather than bottom ash, however, all waste treatment demands a final product that is both inert and reduced in volume. The low viscosity high temperature molten bath which forms the basis of the plasma heating system ensures that these requirements are satisfied. Secondarily, if the waste stream can provide the foundation for a recycle stream, this is an added bonus. Typically, slags or glasses obtained from the plasma heating system can be used to replace aggregate in paving stones, bricks, and road fill.

The chemical properties of these products are such that they can be considered as final waste : regular leach tests on existing plants show that TCLP (Toxicity characteristics Leachate Procedure) results meet the most stringent regulations.