State-of-the-Art Technology Chosen to Clean Up Wastewater from
July 19, 2001
The attorney general of North Carolina
and Smithfield Foods, Inc. have
selected technology adapted by Agricultural
Research Service scientists in Florence, S.C., to clean up and dispose of
manure from swine-production wastewater at a 4,360-pig farm in North
Carolinas Duplin County.
The environmentally superior new technology will be used by Smithfield Foods
to replace current lagoons for cleaning up wastewater in the states hog
operations, according to ARS soil scientists Matias B. Vanotti and Patrick G.
Hunt at the ARS Coastal Plain Soil,
Water and Plant Research Center in Florence.
Swine production in the United States is increasing rapidly. In North
Carolina alone, it grew from 2.6 million hogs in 1990 to more than 9 million in
1997. The expansion has caused monumental waste-treatment problems that are one
of the regions greatest environmental issues.
These problems are related to flushing waste from high-density confinement
facilities into anaerobic lagoons and then applying the wastewater to cropland.
Besides nitrogen, swine manure contains phosphorus and other chemicals that can
fertilize plants. But land application can become problematic when more manure
nitrogen is applied than crops or forage can use.
Vanotti, Hunt and a team of ARS colleagues devised an innovative way to
remove the ammonia form of nitrogen from swine manure quickly, effectively and
relatively inexpensively. They adapted a Japanese state-of-the-art technology
for treating municipal wastewater with large populations of nitrifying bacteria
entrapped in polymer gel pellets.
The full-scale treatment system to be built in Duplin County will separate
solids and liquids, make a soil-less growth medium from the solids, remove the
nitrogen and phosphorus from the wastewater, and recycle clean water for the
cleaning of the swine houses.
For more details, see the July issue of Agricultural Research.
ARS is the U.S. Department of
Agricultures chief scientific research agency.