NEWS TECHNOLOGY Continuous emissions monitor for heavy metals patented A continuous emissions monitor (CEM) that measures heavy met als in combustion exhaust gases has been approved for a patent. The technology, developed by Massachusetts Institute of Tech nology (MIT) researchers, is one of several efforts under way to develop CEMs that will enable EPA to regulate metals in hazard ous waste combustion exhaust, said Scott Rauenzahan of EPA's Office of Solid Waste. There is significant interest among communities, environ mental groups, and the hazard ous waste incinerator industry in developing continuous emissions monitoring for metals, Rauenza han said. Rauenzahan currently is writ ing regulations for continuous monitoring of metals under the Clean Air Act in order to have them ready to publish when the CEM technology is available. He has written draft regulations to set CEM standards for several pollutants but cannot publish any for metals until there is a com mercially available technology. EPA plans to solicit proposals for demonstrating multimetal CEM technology this spring, he said. Lab tests showed that the monitor developed at MIT's Plasma Fusion Center can detect three or four metals simulta neously at part-per-billion levels, said David Rhee, one of the MIT researchers. It uses a microwavegenerated plasma to excite metals in the exhaust gas; a fiber-optic bundle relays the light produced to a spectrometer. The technology was tested on a pilot scale last fall, monitoring the exhaust of a soil-vitrifying, dc arc furnace at MIT, Rhee said. Developers are calibrating the jjj monitor for quantitative monitorin ing of furnace exhaust, said MIT ζ researcher Paul Woskov. ο 5 MIT is now seeking a commer< cial partner. The monitor could ^ be commercially available within "• a year as a device that can indis cate metals' presence but not
MIT's monitor uses a microwave-gener ated plasma to excite metals, making them visible to a spectrometer through a bun dle of fiber-optic cables (white tube near base of flame).
quantity, Woskov said. It will take a couple more years to develop a commercial CEM capable of quantifying metals, he said. Rauenzahan estimated it would be five years before a com mercial multimetal CEM is avail able. He said he was "somewhat
excited" about MIT's process, but he noted that other approaches also are being developed. He identified other technologies as laser sparking spectroscopy, X-ray fluorescence, and direct induc tively coupled plasma injection. "There are about a dozen devel opers trying to come up with a way of doing this," agreed Greg Barthold, American Society of Mechanical Engineers' assistant director of research. MIT's monitor is scheduled for additional tests next summer for radionuclides, specifically pluto nium, in incinerator gases, at the Energy Department's (DOE) Pa cific Northwest National Labora tory (Richland, WA), Woskov said. Development of the monitor was funded under a DOE program. —DANIEL SHANNON
California evaluates smog-eating automotive coating technology The effectiveness of a new auto mobile coating designed to de stroy urban ozone and carbon monoxide is being evaluated by California. Pending review of new road test results by the California Air Resources Board (CARB), the technology could soon be in use in the state's smog-plagued cities. Developed by Englehard Corp. (Iselin, NJ), the PremAir technology is a radiator or air-conditioning condenser coating that destroys ozone and carbon monoxide di rectly as they come in contact with it during vehicle operation. According to Jerry Martin, a CARB staff member, the board put the PremAir coating on the "fast track" after learning of the company's plans to conduct road tests in Los Angeles. Should CARB find, after evaluating the data, that the coating eliminates signif icant amounts of ozone, the tech nology could be one of the black box technologies California in cludes in its air quality imple mentation plan, Martin said.
Preliminary results from the road tests show the technology achieved an 80% ozone conver sion average and a range of con version between 70% and nearly 100%, according to Englehard's Diane Lenci. CARB will not dis cuss results until after publication of its report, which is expected later this month. But even if the device destroys 80% of the ozone it contacts, CARB members are skeptical that the technology will significantly affect ambient air quality, Martin said. The high traffic density on freeways generates large amounts of nitrogen oxides, which scav enge ozone, he said. "You would have an ozone-eating device in an area where there is less ozone." If the results of CARB's evalua tion are positive, Martin said, CARB will likely discuss at its next meeting in February how the technology could be used to help reduce smog in California cities. —DANIEL SHANNON
VOL. 29, NO. 12, 1995 / ENVIRONMENTAL SCIENCE & TECHNOLOGY • 5 4 3 A
