There’s Money in Managing Manure--When It’s Done Right

New and expanding swine production facilities in North Carolina are required to use manure management systems that meet the strictest environmental performance standards in the nation. Fortunately, Agricultural Research Service (ARS) scientists and cooperators have developed a system that exceeds state benchmarks for controlling pollutants from swine farms.

Soil scientists Matias Vanotti and Ariel Szogi worked with Super Soil Systems USA of Clinton, N.C., to develop a second-generation system that met North Carolina’s environmental standards for manure management. As would be expected for new technologies, significant cost reductions were achieved by innovations and on-farm testing. The revamped system was two-thirds less expensive to build and operate than the first-generation system, which was tested in 2003.

The two researchers work at the ARS Coastal Plains Soil, Water and Plant Research Center in Florence, S.C. For this full-scale project, they collaborated with ARS microbiologist Patricia Millner at the agency’s Environmental Microbial and Food Safety Laboratory in Beltsville, Md., and ARS chemist John Loughrin at the agency’s Animal Waste Management Research Unit in Bowling Green, Ky.

The new on-farm treatment system used solid-liquid separation and nitrogen and phosphorus removal processes. It removed high levels of several pollutants from manure wastewater, including almost all of the pathogens, odor-causing constituents and ammonia. Replacing anaerobic-lagoon-based systems with the new technology also reduced greenhouse gas emissions by 97 percent.

Animal health and production also benefited. Swine daily weight gain increased, feed conversion improved, animal mortality decreased and 5.6 percent more hogs were sold per growing cycle.

Separated manure solids were converted in a centralized facility into composted materials and used for organic plant fertilizer, soil amendments and plant growth media. Producers can also profit from the new system by selling greenhouse gas emission reduction credits and water quality credits.

The new technology could help swine-producing states protect existing jobs and keep the door open for future job expansion. This technology was featured in a chapter of “Manufacturing Climate Solutions: Carbon-Reducing Technologies and U.S. Jobs,” published in 2008 by Duke University’s Center on Globalization, Governance & Competitiveness.

U.S. Patent Application Serial No. 11/820,396 was filed for this system on June 19, 2007.

ARS is the principal intramural scientific research agency of the U.S. Department of Agriculture.