Management practices from large-scale swine production facilities have resulted in the increased collection and storage of manure for off-season fertilization use. Odor produced during storage has increased the tension among rural neighbors and among urban and rural residents, and greenhouse gas emissions may contribute to climate change. Production of these compounds from stored manure is the result of microbial activity of the anaerobic bacterial populations present during storage. We have been studying the bacterial populations of stored manure to develop methods to reduce bacterial metabolic activity and production of gaseous emissions, including the toxic odorant hydrogen sulfide produced by sulfate-reducing bacteria. Quebracho and other condensed tannins were tested for effects on total gas, hydrogen sulfide, and methane production and levels of sulfate-reducing bacteria in in vitro swine manure slurries. Quebracho condensed tannins were found to be most effective of tannins tested, and total gas, hydrogen sulfide, and methane production were all inhibited by greater than 90% from in vitro manure slurries. The inhibition was maintained for at least 28 days. Total bacterial numbers in the manure were reduced significantly following addition of quebracho tannins, as were sulfate-reducing bacteria. These results indicate that the condensed tannins are eliciting a collective effect on the bacterial population, and the addition of quebracho tannins to stored swine manure may reduce odorous and greenhouse gas emissions.
Why Would We Want to Inhibit Gas Production of Stored Manure?
Develop methods for reducing odor and emissions from stored swine manure.
What Did We Do?
Tested the effects of addition of condensed tannins to in vitro swine manure slurries on production of total gas, hydrogen sulfide, methane, and on the levels of hydrogen sulfide-producing sulfate reducing bacteria.
What Have We Learned?
Addition of condensed tannins to in vitro swine manure slurries reduces production of total gas, with quebracho condensed tannins being the most effective. 0.5% w/v Quebracho condensed tannins reduced total gas, hydrogen sulfide, and methane by at least 90% over a minimum of 28 days. Levels of sulfate reducing bacterial were also significantly reduced by addition of the tannns. This technique should assist swine producers in lowering emission and odors from stored manure.
We are interested in scaling up the testing to on-farm sites and also testing the tannins for reducing foaming from manure storage pits.
Terence R. Whitehead, Research Microbiologist, USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604, email@example.com
Cheryl Spence, USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604
Michael A. Cotta, USDA-ARS-National Center for Agricultural Utilization Research, Peoria, IL 61604
Whitehead, T.R., Spence, C., and Cotta, M.A. Inhibition of Hydrogen Sulfide, Methane and Total Gas Production and Sulfate-Reducing Bacteria in In Vitro Swine Manure Slurries by Tannins, with Focus on Condensed Quebracho Tannins. (2012) Appl. Microbiol. Biotech. http://link.springer.com/article/10.1007/s00253-012-4562-6/fulltext.html
Development and Comparison of SYBR Green Quantitative Real-Time PCR Assays for Detection and Enumeration of Sulfate-Reducing Bacteria in Stored Swine Manure. (2008) J. Appl. Microbiol. 105: 2143-2152. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2672.2008.03900.x/pdf
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