(506e) Study on Swine Manure Foaming to Understand Its Major Reason and Its Relations to Industrial Products

In the past few years, a sharp increase of pit-foaming is discovered in swine production facilities. The foams on the swine manure hold significant amount of methane gas, limited the space for manure storage and creates a potential safety hazard. Cases of flash fires and explosions were reported recently in Midwestern states, causing significant assets loss and worker injuries. This research combined with the field sampling and lab simulation to study the foaming mechanism, including manure compositional analysis, microbial community analysis and surfactant identification. Microbial community analysis results show that unlike many foaming cases in wastewater treatment facilities, the manure foaming was not induced by the massive growth of filamentous bacteria. Instead, it is indicated from the lab simulations that the increased concentration of long chain fatty acids together with solid particles in manure solution could initiate the generation of stable foam bubbles. Analysis on solid particles suggests that protein contributes as the major surfactant in manure solution, and further proteomic study will specify which group of protein is mainly involved in this foaming. This research also explored the possibility of some feeding factors that may be related to this foaming phenomenon, like dried distiller grains solubles (DDGS) addition in pig diets and lower digestibility of feed in the pork production. Since DDGS is a major by-product of corn ethanol industry, this will help to improve the industrial process design and provide more applicable products.