FOWL MANURE MAY HELP THE ENVIRONMENT
Disposal of animal manure is one of the biggest problems facing
agriculture today. Now, scientists with the Agricultural Research Service
may have found a way to convert some types into a material that can be
used to help keep the environment clean.
Currently, animal waste is valued at between $3 and $10 per ton, and most
of it is used as a fertilizer. Unfortunately, when added to soil, a
buildup of nutrients--namely nitrogen, phosphorus and potassium--can
occur, especially if it's applied repeatedly to the same area. This can
lead to non-point source pollution runoff into rivers and streams as well
as nitrogen leaching into shallow groundwater, which has caused some
states to introduce legislation that would limit such applications.
Isabel Lima, a chemist in the Commodity Utilization Research Unit at ARS'
Southern Regional Research Center in New Orleans, La., has discovered a
potentially less detrimental way to utilize animal waste. She has found a
way to convert it into activated carbons, which soak up unwanted
pollutants and can be used for environmental remediation.
Right now, bituminous coal and coconut shells are the two materials most
commonly used by U.S. manufacturers to make activated carbons. However,
coal is an expensive and nonrenewable resource, costing between $60 and
$80 per ton, while coconut shells are not readily available here.
So far, Lima has focused her studies on poultry litter, which is
inexpensive and available. When pelletized and activated under specific
conditions, the litter becomes a highly porous material with a large
surface area. In early tests, these carbons performed very well in
adsorbing copper, which suggests they may do well as a wastewater filter
for other metal ions. Their adsorption rate may also make them more cost
effective than carbons currently on the market.
This technology could provide farmers with an acceptable way to
beneficially use their animal manure, especially in environmentally
sensitive areas with dense poultry populations, such as Maryland's eastern
Lima will be presenting her findings at the WEF/AWWA/CWEA Joint Residuals
and Biosolids Management Conference and Exhibition in Baltimore, Md.,
ARS is the U.S. Department of Agriculture's chief scientific research