Peter McIntyre and a group of colleagues at Texas A&M University have developed a cost-effective device to produce high energy electron beams that can break down harmful organic molecules in water - and destroy bacteria such as anthrax in food - or even on mail.
"William Cooper at the University of North Carolina showed that high-powered beams of electrons are highly effective in destroying organic contaminants in water," McIntyre said. "The difference here is that we've upped the power produced and reduced the cost, producing four times more energy at a unit cost per kilowatt five times less than any other such instrument."
Over the past three years, McIntyre's team has developed the Coupled Multiplier Accelerator (CMA), a completely self-contained high-power electron accelerator that produces 100 kilowatts of beam power at one million volts, supports multiple independent beams and has a total capital cost of less than $500,000, representing a new, more affordable generation of e-beam technology.
Basically, McIntyre's machine produces an electron beam like that found in CRT's. The beam raster scans the contaminated water like cathode rays scan the inside of a TV tube, ionizing the water to produce free radicals and inducing both oxidation and reduction reactions which "digest" organic contaminants.
"The same process causes double breaks in bacterial DNA bonds, killing them," McIntyre explained. "It could be used to kill anthrax spores, which are five times more difficult to kill than bacteria like e-coli, because the spores encase the anthrax in a hard protective shell."
McIntyre expects the first commercial CMA to be in place at a Houston-area petrochemical plant by December. The technology has been licensed to a small Texas company which will operate the system there, where it will be used to treat a condensate stream containing methyl terbutyl ether (MTBE), a gasoline additive. MTBE is harmful to humans, and some of its secondary breakdown products, like formaldehyde and acetone, are even more toxic.
"The CMA is key to making lots of e-beam, supporting multiple beams needed for effective treatment in most real-world applications and doing it with a simple, reliable system that is economical for industrial applications," McIntyre said. "The basis of the technology is in every automobile - the alternator."
McIntyre's CMA uses two 125 hp electronic motors to drive 16 alternators. Each alternator outputs a three-phase alternating current that is boosted by a transformer and rectified by a voltage multiplier circuit to produce high-voltage direct current. The 16 modules are connected in series to produce up to two megavolts of beam energy with up to 200 kilowatts of power. The entire accelerator - voltage source, electron guns and accelerator columns - is housed in a 14-foot-long, 9-foot-diameter pressurized steel vessel.
McIntyre's CMA project team includes Texas A&M professors Akhdior Sattarov (physics), Bill Batchelor (civil engineering) and Bruce Herbert (geophysics) and Charles Meitzler of Sam Houston State University, as well as six graduate students, four undergrads and four professional technicians.
"You might say that man is the easiest organism to kill, but anthrax is one of the hardest," McIntyre observed. "We hope the CMA can equalize the odds a bit."