A new technology for cleaning up hazardous waste
using a sugar made from corn starch has won a $830,000 grant from
the U.S. Department of Defense.
Thomas Boving, an assistant professor of geosciences at the
University of Rhode Island, with colleagues from the University of
Arizona, the Colorado College of Mines, and the University of
Texas-San Antonio, has developed the innovative system to quickly
and economically remove a wide range of toxic materials from
groundwater using a substance called cyclodextrin.
"Cyclodextrin is a type of sugar made from corn starch," said
Boving, a native of Germany who joined the URI faculty in 1999.
"It's better than other technologies for cleaning up hazardous
materials because it's nontoxic and leaving it underground for a
period of time causes no harm."
Cyclodextrins, which are known chemically as
cyclicoligosaccharides, were discovered 100 years ago. They have
been used in the pharmaceutical industry to make drugs more water
soluble and to increase their bio-availablity and stability.
Cyclodextrins can also be used as processing aids to isolate
compounds from natural sources and to remove unwanted compounds such
as cholesterol from food products. But Boving's application of
cyclodextrin to hazardous waste is a first.
Due to the chemical structure of cyclodextrin, many toxic
materials like solvents, pesticides, and polycyclic aromatic
hydrocarbons are attracted to it.
To clean up a site, Boving will inject quantities of cyclodextrin
solution into contaminated soil and groundwater. After allowing the
material to move through the earth and attract the contaminants,
Boving will pump the cyclodextrin out of the ground.
A military installation in Virginia was selected as the field
demonstration site for Boving's technology. Beginning in May, his
team will conduct preliminary testing of the soils and groundwater
at the test site and prepare the field study. The actual field test
will take place over four months during the summer of 2002.
The most innovative part of the cleanup process is how costly
cyclodextrin is recycled. Boving and his colleagues from the URI
Chemical Engineering Department have developed a method of stripping
the contaminants from the cyclodextrin so the expensive substance
can be used again.
Boving has focused his research on removing contaminants from
water. Last year, he developed a system of separating pollutants
from storm water runoff before it reaches Narragansett Bay by using
shredded aspen wood. The wood sucessfully removed pyrene, a human
carcinogen, from roadway runoff.
Boving says that this grant from the Department of Defense's
Environmental Security Technology Certification program will allow
him to prove the benefits and advantages of his technology for
cleaning up aquifers. These geologic formations that hold water
underground have been contaminated by military or industrial
chemicals in many places.
"No one who has to clean up a site is going to use an unproven
system," Boving said, "so this grant will allow us to demonstrate
that our system is quicker and more economical than the most
commonly used methods today."
The Department of Defense controls about 28,000 sites that must
be cleaned up, and at least 500 of those contain the contaminants on
which Boving's cyclodextrin system is expected to perform best. In
addition, there are thousands of other sites around the country that
need cleaning. The government estimates it will cost about $1
trillion to clean up all of them.
"There is a tremendous amount of work to do to clean up the
thousands of toxic sites in the country," Boving said. "Obtaining
the military's seal of approval for our system is a big step in the
right direction for us."