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Re: [SANET-MG] New technology removes viruses from drinking water
Thanks for the important development in water technology. The patent
application for the process is:United States Patent Application 20060249465
Jin; Yan ; et al. November 9, 2006
Removal of microorganisms and disinfection byproduct precursors using
elemental iron or
A process for removing microorganisms and/or precursors of disinfection
by-products from a medium sought to be
treated comprising treating the medium with one or more elements capable
of forming an oxide, a hydroxide, and/or
an oxyhydroxide through corrosion is disclosed. A system for effecting
the removal or inactivation of
microorganisms disinfection by-product precursors is also contemplated
Neal Van Milligen wrote:
New technology removes viruses from drinking water
3:21 p.m., Feb. 26, 2007--University of Delaware researchers have
developed an inexpensive, nonchlorine-based technology that can remove
harmful microorganisms, including viruses, from drinking water.
UD's patented technology, developed jointly by researchers in the
College of Agriculture and Natural Resources and the College of
Engineering, incorporates highly reactive iron in the filtering
process to deliver a chemical “knock-out punch” to a host of notorious
pathogens, from /E. coli/ to rotavirus.
The new technology could dramatically improve the safety of drinking
water around the globe, particularly in developing countries.
According to the World Health Organization (WHO), over a billion
people--one-sixth of the world's population--lack access to safe water
Four billion cases of diarrheal disease occur worldwide every year,
resulting in 1.8 million deaths, primarily infants and children in
developing countries. Eighty-eight percent of this disease is
attributed to unsafe water supplies, inadequate sanitation and hygiene.
In the United States, viruses are the target pathogenic microorganisms
in the new Ground Water Rule under the Environmental Protection
Agency's Safe Drinking Water Act, which took effect on Jan. 8.
“What is unique about our technology is its ability to remove
viruses--the smallest of the pathogens--from water supplies,” Pei
Chiu, an associate professor in UD's Department of Civil and
Environmental Engineering, said.
Chiu collaborated with Yan Jin, a professor of environmental soil
physics in UD's plant and soil sciences department, to develop the
technology. They then sought the expertise of virologist Kali Kniel,
an assistant professor in the animal and food sciences department, who
has provided critical assistance with the testing phase.
“A serious challenge facing the water treatment industry is how to
simultaneously control microbial pathogens, disinfectants such as
chlorine, and toxic disinfection byproducts in our drinking water, and
at an acceptable cost,” Chiu noted.
Viruses are difficult to eliminate in drinking water using current
methods because they are far smaller than bacteria, highly mobile, and
resistant to chlorination, which is the dominant disinfection method
used in the United States, according to the researchers.
Of all the inhabitants of the microbial world, viruses are the
smallest--as tiny as 10 nanometers. According to the American Society
for Microbiology, if a virus could be enlarged to the size of a
baseball, the average bacterium would be the size of the pitcher's
mound, and a single cell in your body would be the size of a ballpark.
“By using elemental iron in the filtration process, we were able to
remove viral agents from drinking water at very high efficiencies. Of
a quarter of a million particles going in, only a few were going out,”
The elemental or “zero-valent” iron (Fe) used in the technology is
widely available as a byproduct of iron and steel production, and it
is inexpensive, currently costing less than 40 cents a pound
(~$750/ton). Viruses are either chemically inactivated by or
irreversibly adsorbed to the iron, according to the scientists.
*Technology removes 99.999 percent of viruses*
The idea for the UD research sprang up when Jin and Chiu were
discussing their respective projects over lunch one day.
Since joining UD in 1995, Jin's primary research area has been
investigating the survival, attachment and transport behavior of
viruses in soil and groundwater aquifers. One of the projects, which
was sponsored by the American Water Works Association Research
Foundation, involved testing virus transport potential in soils
collected from different regions across the United States. Jin's group
found that the soils high in iron and aluminum oxides removed viruses
much more efficiently than those that didn't contain metal oxides.
“We knew that iron had been used to treat a variety of pollutants in
groundwater, but no one had tested iron against biological agents,”
Chiu said. So the two researchers decided to pursue some experiments.
With partial support from the U.S. Department of Agriculture and the
Delaware Water Resources Center, through its graduate fellowship
program, the scientists and their students began evaluating the
effectiveness of iron granules in removing viruses from water under
continuous flow conditions and over extended periods. Two
bacteriophages--viruses that infect bacteria--were used in the initial
Dr. Kali Kniel <http://www.udel.edu/PR/UDaily/2007/feb/Kniel-lg.jpg>
/Kali Kniel, a virologist at UD, has provided critical expertise in
documenting the UD technology's effectiveness in removing pathogens
such as rotavirus, shown in the magnified view at right. Rotavirus is
the number-one cause of diarrhea in children./
Since then, Kniel has been documenting the technology's effectiveness
against human pathogens including /E. coli/ 0157:H7, hepatitis A,
norovirus and rotavirus. Rotavirus is the number-one cause of diarrhea
in children, according to Kniel.
“In 20 minutes, we found 99.99 percent removal of the viruses,” Chiu
said. “And we found that removal of the viruses got even better than
that with time, to more than 99.999 percent.”
The elemental iron also removed organic material, such as humic acid,
that naturally occurs in groundwater and other sources of drinking
water. During the disinfection process, this natural organic material
can react with chlorine to produce a variety of toxic chemicals called
“Our iron-based technology can help ensure drinking-water safety by
reducing microbial pathogens and disinfection byproducts
simultaneously,” Chiu noted.
*Applications in agriculture and food safety*
Besides helping to safeguard drinking water, the UD technology may
have applications in agriculture.
Integrated into the wash-water system at a produce-packing house, it
could help clean and safeguard fresh and “ready to eat” vegetables,
particularly leafy greens like lettuce and spinach, as well as fruit,
according to Kniel.
“Sometimes on farms, wash-water is recirculated, so this technology
could help prevent plant pathogens from spreading to other plants,”
This UD research underscores the importance of interdisciplinary study
in solving problems.
“There are lots of exciting things you can discover working together,”
Jin said, smiling. “In this project, we all need each other. Pei is
the engineer and knows where we should put this step and how to scale
it up. I study how viruses and other types of colloidal particles are
transported in water, and Kali knows all about waterborne pathogens.
“Our hope is that the technology we've developed will help people in
our country and around the world, especially in developing countries,”
Currently, the Centre for Affordable Water and Sanitation Technology
in Calgary, Canada, is exploring use of the UD technology in a
portable water treatment unit. Since 2001, the registered Canadian
charity has provided technical training in water and sanitation to
more than 300 organizations in 43 countries of the developing world,
impacting nearly a million people.
The University of Delaware is pursuing commercialization opportunities
for the research. Patents have been filed in the United States,
Canada, France, Germany and Switzerland. For more information, contact
Bruce Morrissey, UD director of technology development, Office of the
Vice Provost for Research and Graduate Studies, at [firstname.lastname@example.org
<mailto:email@example.com>] or (302) 831-4230.
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