[CPEO-MEF] "Acetone Speeds Remediation of TNT-Contaminated Soil"

[CPEO Moderator <cpeo@cpeo.org>]

To Read INEEL's June 1999 Press release go to: 
http://environment.inel.gov/press/contextnews.cfm?ID=33



The following is from the GNET website
http://www.gnet.org/Coldfusion/News_Page2.cfm?NewsID=9963

Acetone Speeds Remediation of TNT-Contaminated Soil 
EarthVision Environmental News 

04/21/00 

 IDAHO FALLS, ID, April 21, 2000 - Last June, researchers announced they
were using a unique composting process that included ingredients such as
potatoes, manure and acetone to see if it could remediate chunks of
trinitrotoluene (TNT) and TNT-contaminated soils. Although using composting
to remove the explosive, which is often found at old gunnery ranges and
military wastewater lagoons, wasn't news, the addition of acetone was. Now,
results are in and the researchers working at the Idaho National
Engineering and Environmental Laboratory (INEEL) have declared the method a
success. By the end of the process, the TNT is completely degraded and the
acetone evaporates. 

 INEEL microbiologists Corey Radtke, Richard M. Lehman and Francisco F.
 Roberto also found the microbial populations at work degrading the
explosive lived quite happily under the modified conditions. The report by
has been published in Bioremediation Journal. 

 "The beauty of this method is that when the experiment is done," said
INEEL microbiologist Radtke, "the treated soil can go into INEEL's landfill
and we never have to worry about it again." 

 Part of the land on which the INEEL sits was a World War II era Naval
gunnery range. As a result of military activities, particles of TNT ranging
in size from about 56 grams to less than a hundredth of a gram contaminate
about a thousand cubic yards of soil. Although the TNT isn't a likely
explosion hazard, the US Environmental Protection Agency (EPA) has declared
TNT a possible human carcinogen under its Integrated Risk Information
System. As a part of its overall environmental mission and to safeguard the
health of its workers, the INEEL said it is trying to clean up the TNT. 

 Even though TNT is considered carcinogenic, naturally occurring microbes
will "eat" it if the conditions are right. However, chunks of TNT aren't
broken down very efficiently so the TNT would have to be treated to get the
size down. Microbiologists knew from earlier studies that acetone could
extract TNT from the dirt but once they applied the acetone, they couldn't
find a way to recover the solvent containing the dissolved explosive. So,
they decided to try composting the contaminated soil without first removing
the acetone. 

 What the team found was without the acetone the compost reactions still
had an average of 2000 parts per million TNT after 20 days. The addition of
acetone allowed the microbes to degrade the TNT to less than 500 parts per
million within one day and the concentration of TNT was down to safe levels
within a week. 

 The researchers note that the compost doesn't heat up as fast when acetone
is added, but that the temperature - usually an indication of how the
amount of microbial activity - does not seem to be important for TNT
degradation. They suggest that since the microbes can use acetone as a food
source, its addition creates such a feast that the microbes don't have to
work as hard to degrade the explosive substance. 

 The team has already scaled up its experiments to 30-gallon batches of
soil at a time. However, due to INEEL's strict safety and documentation
requirements, the researchers say they don't know how much money this
method could save the national lab. The INEEL has about a thousand cubic
yards of TNT-contaminated soil, or enough to fill about 40 garbage trucks. 

 The title of the published article is Increased biotransformation
efficiency of chunk-TNT contaminated soil using acetone pretreatments,
found in Volume 4, Issue 1, pages 57-67 of Bioremeditation Journal. 
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