Estimation of emission factor for odorants released from swine excretion slurries

In this study, the odorant emission rates from excretory wastes collected in sealed containers from a large swine facility were determined offsite in a laboratory using both raw slurry from ([1] windowless pigpen (WP) and [2] open pigpen (OP)) and treated waste samples ([3] composting facility (CF) and [4] slurry treatment facility (SF)). The emission rates of up to 41 volatile odorants were measured for 100 g waste samples (of all four types) in a 0.75 L impinger with an air change rate of 8 h^-1. The initial emission rates (mg kg^-1·h^-1) for the most dominant species from each waste type can be summarized as: (1) WP: NH₃ (16.3) and H₂S (0.54); (2) OP: H₂S (1.78), NH₃ (1.69), and p-cresol (0.36); (3) CF: NH₃ (7.04), CH₃SH (0.30), and DMS (0.12); and (4) SF: NH₃ (11.7), H₂S (11.7), and p-cresol (0.25). Accordingly, the emission factors for the key odorant (m_E, kg·pig^-1)) for fattening pigs in the WP and OP facilities of S. Korea were extrapolated as 3.46 (NH₃) and 0.38 (H₂S), respectively. The emission factors were estimated assuming exponentially decaying emission rates and slurry production rates obtained from the literature.