Editor's Note: This pollution prevention article is one in a series written for the Daily Newsbulletin by Sonja Salzman of the Laboratory's Pollution Prevention (RRES-PP) Program Office. To learn more about pollution prevention efforts at the Laboratory, go to http://emeso.lanl.gov/ online.

Plasma could be used as pollution control tool

A new process called silent discharge plasma is being developed at Los Alamos that destroys organic air pollutants. It also has potential applications for cleaning up contaminated industrial sites, emissions from burning oil containing organic contaminants, odors and regulated air pollutants from food processing.

Plasma is a mixture of ionized and uncharged gas molecules found in places such as the corona of the sun or inside fluorescent light bulbs. It is created when electrical energy discharges in the gas and causes the formation of ions. When humid air is ionized, very reactive chemical types are generated from oxygen, nitrogen and water. These active species can react with organic pollutants and break apart their bonds. When an organic pollutant is broken apart, only carbon dioxide, water and other mineral compounds remain. If the organic pollutant contains chlorine, then mineral acid is one of the products. Carbon dioxide and water are inert substances and mineral acids can be neutralized into water and an inert salt quite easily. The fact that the reaction takes place at ambient temperatures and avoids the creation of toxic byproducts makes plasma a more appealing alternative for pollution control than combustion techniques now being used in certain industrial settings, according to Louis Rosocha of Plasma Physics (P-24).

Rosocha won a $30,000 technology maturation fund award from the Laboratory to assist in bringing the concept from the experimental laboratory stage to the commercially available product stage. These awards are granted to help turn promising research into viable technologies that are commercially desirable.

Plasma processing already has been used successfully to destroy pollutants present in some contaminated soil at McClellan Air Force Base near Sacramento, Calif.

At Tinker Air Force Base near Oklahoma City, Okla., plasma was used to destroy organic pollutants found in groundwater. Contaminated groundwater is pumped into special columns called spargers that cause the organics to become airborne. Plasma destroys these airborne pollutants and clean water is returned to the aquifer.

There are many other potential applications in commercial settings for silent discharge plasma, Rosocha said. Plasma processing could destroy organic pollutants generated by burning oil contaminated with polychlorinated biphenyls (PCBs). Japan and other countries have stockpiles of PCB-containing oil. This oil could be burned to create electricity. However, current pollution control technology does not remove enough dioxins created by the PCB’s to be safe for humans in the surrounding area. Plasma control technology can potentially be added to the pollution control equipment of exhaust stacks at a power plant to destroy all of the dioxins and other organic pollutants generated by burning this oil, Rosocha explained.

Silent discharge plasma also has potential value for food processing applications. Most food factories generate airborne organic compounds during the normal course of production. While these organic emissions are not necessarily toxic, some have an overwhelming or unpleasant smell that is annoying to nearby neighbors. Factories could potentially be fitted with plasma processing units to destroy these organic emissions.

Small specialty roasting machines, like those used to roast coffee in stores, can be retrofitted with plasma processing equipment to eliminate organic emissions. Some restaurants, especially those that grill or charbroil food, might also be able to make use of plasma processing technology.

For more information about this project, call Rosocha at 7-8493 or write to rosocha@lanl.gov by electronic mail.

For more information about pollution prevention efforts at the Lab, go to http://emeso.lanl.gov online.

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