U.S. Water News Online
CHAPEL HILL, N.C. -- During disasters, civilian or military
conflicts and wilderness recreation, disinfecting drinking, cooking
and wash water can make the difference between getting sick and
staying well, but chemical disinfectants such as chlorine and fuels
to boil water often are unavailable in the field.
To help solve that problem, researchers have developed a
battery-powered disinfecting "pen." The device electrochemically
generates mixed oxidants from a salt solution that individuals can
use to purify drinking water.
Tests of the invention recently took place at the University of
North Carolina at Chapel Hill's Environmental Health Microbiology
Laboratories. Dr. Mark D. Sobsey, professor of environmental sciences
and engineering at the UNC-CH School of Public Health, led the effort
with doctoral students Maren E. Anderson and Julie A. Kase.
Los Alamos Technical Associates and MIOX Corp. of Albuquerque
developed the pen, and the latter funded the UNC-CH research. Results
of the independent analysis were presented at a news conference at
the 100th annual general meeting of the American Society for
Microbiology in Los Angeles late last month.
Investigators evaluated the new battery-powered tool to see how
well it inactivated waterborne parasites, viruses, and bacteria.
Several alternative pen cell designs also were tested by seeding
oxidant solutions generated from the pen with test microbes,
including highly chlorine-resistant Cryptosporidium parvum, a
major source of contamination in water.
"There was dramatic -- more than 99.99 percent -- reduction of all
test bacteria and viruses within one to 10 minutes," Sobsey said.
"Considerable inactivation of C. parvum was also achieved
within 90 minutes, the amount depending on the design of the pen
Experiments demonstrated that the miniature pen cell
electrochemically generated a mixture of oxidants from a salt
solution that was able to inactivate C. parvum eggs, as well
as bacterial spores, bacteria, and viruses to produce safer drinking
water in minutes, he said.
"The pen cell makes it possible for people to easily and quickly
have safe supplies of personal drinking water in remote and isolated
areas and during situations where water supplies are at risk of being
contaminated," Sobsey said. "There is a very big need for this, and
it almost certainly will save lives."
Users put a small amount of water into the pen, and then salt
pellets dissolve in the water, which comes in contact with
battery-powered electrodes, he explained. Within 30 or so seconds of
flicking a switch, a chemical reaction known as electrolysis
generates chlorine and other oxidants from the saltwater.
"The solution contents are then added to a quart bottle of water
or a canteen," Sobsey said. "This delivers enough oxidants to
disinfect the water in 10 minutes even better than plain chlorine
does, and then the water can be drunk safely."
To protect soldiers, the Defense Advanced Research Projects Agency
(DARPA) paid for developing the MIOX Disinfection Pen, which is seven
inches long and weighs four ounces. A lighter, less expensive version
is being designed for the outdoor recreation market.
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