The United States is one of the top 3 countries in producing pork. It generates lots of profits and jobs, but this industry also generates lots of odor and gaseous emissions. This unwanted side effect is always one of the biggest concerns in the pork industry. NH3 and H2S are extremely harmful to the health of humans and animals, especially during the manure pump-out season, there is always news about people or livestock fainted or fatal due to the exposure of NH3 and H2S. Volatile organic compounds (VOCs) are the main sources generating odor. Small particle matters in the air will carry these odorous VOCs to miles away and affecting their living environment. Greenhouse gases (GHG) will accumulate in the atmosphere and causes climate changes. Manure additive is one of many ways to potentially mitigate the emissions. It is relatively less expensive compared with other methods, and easy to apply without changing the current swine farm’s structures. We tested 12 marketed products for their efficacy in mitigating emissions of target gases from stored manure using the recommended dosages from the labels of the products and a pilot-scale system simulating manure storage in a deep pit. The results were statistically insignificant with the comparisons of the untreated manure for all 12 products tested. Most of the products advertise a not-defined microbial mode of action without specific information about a proprietary blend of microbes acting as an active ingredient. One possible reason that leads to this result is that the recommended dosages at this pilot-scale are not effectively addressing the complexity of microbial activity in manure itself.

Key Findings
• The recommended dosages from the 12 products tested in this research did not show statistically significant reductions on the targeted gases and had no impact on manure properties.
• Manure properties from different farms were statistically different from each other.