|VAN WEELDEN, MARK - Iowa State University|
|ANDERSON, DANIEL - Iowa State University|
|PEPPLE, LAURA - University Of Illinois|
Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2015
Publication Date: 1/1/2016
Citation: Van Weelden, M., Anderson, D., Kerr, B.J., Trabue, S.L., Peeple, L. 2016. Impact of fiber source and feed particle size on swine manure properties related to spontaneous foam formation during anaerobic decomposition. Bioresource Technology. 202:84-92. doi: 10.1016/j.biortech.2015.11.080.
Interpretive Summary: The accumulation of foam on the surface of deep pit manure storages is a serious concern for pork producers. Foam accumulation can significantly reduce the amount of space available for manure storage, which may force farm managers to apply manure during untimely seasonal windows or seek other means of manure storage. In addition, foam accumulation can impact safety at swine facilities where foam has the capacity to trap gases (i.e., methane) produced by the anaerobic decomposition of swine manure, and if the foam layer is broken, the release of methane may be rapid enough for explosive concentrations to occur in the barn. Results of this study indicate that foaming properties of the manure were impacted by feed grind size and fiber source. Factors that reduced digestibility (bigger grind size, more neutral detergent fiber) resulted in increased foaming properties. It was hypothesized that this was due to increased microbial activity due to a greater amount of carbon in the manure. Aging the manure resulted in more fine silt sized particles (2 to 25 microns), which play an essential role in stabilizing foam bubbles in this system; however, it did little to alter other foaming properties. Research results described in this report provides scientists and swine producers information on dietary and physical factors that may be associated with foam generation in swine manure storage facilities.
Technical Abstract: Foam accumulation in deep-pit manure storage facilities is of concern for swine producers because of the logistical and safety-related problems it creates. A feeding trial was performed to evaluate the impact of feed grind size, fiber source, and manure age on foaming characteristics. Animals were fed: 1) C-SBM (corn-soybean meal): 2) C-DDGS (corn-dried distiller grains with solubles); and 3) C-Soybean Hull (corn-soybean meal with soybean hulls) with each diet ground to either fine (374 microns) or coarse (631 microns) particle size. Two sets of 24 pigs were fed and their manure collected. Factors that decreased feed digestibility (larger grind size and increased fiber content) resulted in increased solids loading to the manure, greater foaming characteristics, more particles in the critical particle size range (2 to 25 mm), and a greater biological activity/potential. Increased manure age reduced foaming potential characteristics, but increased percent of particles in the 2 to 25 micron range.