Odor characterization from barns and slurry treatment facilities at a commercial swine facility in South Korea

In this study, emission characteristics of major odorants in pig confinement facilities were investigated through comparative analysis between odorant composition and odor intensity. Odorant samples in ambient air were collected from five different paired sampling sites: (1) in- and outside of windowless pig barn, (2) in- and outside of open pig barn, (3) before/after slurry treatment (via liquid fertilization), (4) before/after composting, and (5) two reference background sites on a pig confinement facility. A total of 47 compounds consisting of key offensive odorants (such as reduced sulfur and volatile organic compounds) were measured from each selected site. When the results are compared in terms of odor intensity, a list of odorants (sulfur compounds, volatile fatty acids, phenols, and indoles) were generally seen at enhanced levels on most sites. In two types of pig barn facilities (windowless (‘W’) and open (‘O’)), butyric and valeric acid were the predominant species. The removal efficiency of odorants was quite different between the two slurry treatment approaches of composting and liquid fertilization. Although the efficiencies of odor removal in the former were not sufficient, that of the latter was fairly significant in terms of odor intensity. However, some odorants like hydrogen sulfide, methanethiol, p-cresol, and butyric acid were still retained above the odor threshold level. Accordingly, odorant emissions from animal housing facilities can be characterized most effectively by key odorants such as volatile fatty acids and reduced sulfur species.