Plasma Pyrolysis for Waste Treatment

Plasma torch—based applications for waste treatments include fly ash from incineration processes, asbestos-containing waste, sanitary waste, waste containing organo-halogenated compounds, low-level radioactive waste, and even traditional RDF. In particular, plasma applications represent a very interesting technical solution for the treatment of fly ash from MSW/RDF incineration because the solid by-product, with its extremely low tendency to leaching, can be disposed off as a 

MSW management is a crucial environmental task for all advanced societies, particularly in a context of increasing landfilling restrictions. Incineration can signifi-candy contribute to MSW management. However, MSW (or RDF) incineration has several serious potential environmental impacts that need to be carefully taken into account. 

The most relevant problem originating from MSW incineration is flue gas treatment, since untreated incineration flue gas can contain large amounts of macropollutants (e.g., CO, S02, HC1, NOx, particulates) andmicropollutants (e.g., PAHs, mercury compounds, polychlorinated biphenyls, dioxins, furans). The necessity of reducing polluting emissions to levels compatible with existing regulations dictates the adoption of rather sophisticated- and expensive flue gas treatment sections in incineration plants. 

In addition to this, another, often overlooked issue is the disposal of solid byproducts of the incineration process. MSW incinerators essentially produce two types of solid by-products. The first is the slag, or bottom ash, which is mostly made of the noncombustible fractions of the waste, plus a small fraction of the combustible fraction. The second is fly ash, the particulate material captured in the particulate removal section of the flue gas treatment plant, which is often mixed with various other chemicals used for flue gas treatment. Bottom ash and fly ash are characterized by very high concentrations of PTE, such as lead, mercury, cadmium, and nickel, which can easily leach into the environment. 

The author is thankful to the reviewers M. Di Bonito (Environmental Agency, Nottingham, UK) and C. Sears (Sears Consulting, LLC, USA), whose comments were useful to improve the chapter. 

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