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If Suresh Pillai could fit an ocean into a test tube, his problems would be solved. The Texas A&M University microbiologist has spent years trying to unravel a riddle: How do you collect a reliable test sample that is representative of a huge amount of water?
The problem has long plagued water utilities and the food and beverage industry; however, it has taken on more urgency in the age of terrorism. If America’s enemies decide to launch a biological attack on a major city’s water system, scientists will need a way to quickly identify what organisms or agents are lurking there.
Ali Beskok, assistant professor of mechanical engineering, has proposed a solution: Create a device that corrals harmful bacteria and viruses and removes them from a large quantity of water, then concentrates them for a more accurate test sample.
The researchers say the key may be electricity. Fecal viruses and bacteria, including E. Coli and salmonella, are negatively charged on their surfaces. Therefore, a positively charged electrical field theoretically could be used to herd the pathogens into a container, where they can be concentrated into smaller samples for testing.
After two years of work, under a $129,000 grant from the state of Texas, the researchers think they are on the verge of proving their hypothesis. Now NASA is paying $89,000 to find out whether they are right.
If they are, scientists could one day use Beskok and Pillai’s device to continually, and much more accurately, monitor drinking water supplies, rather than relying on “grab samples”— small volumes of water collected to spot check a larger supply.
The NASA grant will fund a pilot project to build the device, which would channel about five liters of water per hour through hundreds of parallel tubes in a glass or Plexiglas container. The tubes each would be about a quarter of a millimeter wide to ensure that any microbes would pass close enough to electricity conducted by a copper plate. Once the microbes were collected and concentrated, bacteria and viruses from dozens of liters of water would be trapped in about a milliliter of water—about a thimbleful—which then could be tested.
The device would be designed to collect any pathogen that might be in the water, rather than targeting certain bacteria or viruses.
The city of El Paso has offered its water utility as a testing ground. If Pillai and Beskok are successful, they hope the space agency will team them up with NASA scientists and provide more funds for a more comprehensive study.
One day, in addition to its use on Earth, a laptop-size version of the device could be used to ensure the safety of recycled drinking water supplies on the international space station or on future spacecraft heading to the moon or Mars.
For more information contact Dr. A. Beskok at abeskok@tamu. edu or (979) 862-1073.
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