Treatment of hazardous waste using thermal plasmas: garbage, greenhouse gases and more

摘要

Twenty years ago, Nufarm had a problem. The company, which produces agricultural chemicals, had been the target of a protest organised by Greenpeace, whose activists had blocked the pipe discharging waste into the sewer. Greenpeace objected to the presence of dioxins in the waste liquid from Nufarm's process to produce the herbicide 2,4D. Although Nufarm had all the required permits in place for discharge into the sewerage system, they nevertheless decided to search for a technology to treat the waste on site.rnJust 30 km away, CSIRO researchers were experimenting with the electric-arc plasma systems that they applied for welding and cutting of metals, and spraying of heat- and wear-resistant coatings. The researchers reasoned that the high temperatures (up to 20 000 K) and heat fluxes produced in these atmospheric-pressure plasmas could be used to break down any hazardous molecule into constituent atoms.