Evaluation of a Mechanical Foam Mitigation Device in Swine Deep-pit Manure Storage

Abstract. Foam production in deep-pit swine manure storages has become a significant problem for the Midwestern US swine industry in recent years. Pit foaming creates management concerns as well as both animal and worker safety challenges for swine producers. There is an increased risk of flash fires or explosions when substantial foam develops, and foam reduces the effective manure storage capacity. Consequently, a mechanical device to mitigate foam safely and quickly in these facilities was developed. The objective of this study was to assess the efficacy of a purpose-built mechanical foam mitigation device to destroy foam in foaming swine deep-pit manure storages and to evaluate its performance during continuous versus periodic device operation at two different installation locations on a barn. A swine production facility in central Illinois, with a recent history of extensive foam production, was selected to evaluate the mechanical foam mitigation device. The device was tested in three similar barns for both continuous and periodic operation. Most installation locations were at pump-out ports outside the building, with one test run conducted inside a building. Results showed that the device was capable of destroying foam at rates ranging from 3% to 6% of initial foam volume destroyed per hour. Based on this limited testing, periodic operation had an advantage over continuous operation in terms of foam destruction rate in foam depths greater than 0.2 m when the device was installed in a pump-out port. The device was found to be capable of reducing foam depth over a radial distance of at least 21 m when installed in a pump-out port and operated continuously.