Estimation of emission factor for odorants released from swine excretion slurries

Abstract

In this study, an odorant emissions inventory was investigated with respect to excretory wastes produced from two types of pigpen facilities (windowless vs. open) in South Korea. To this end, emissions from different types of swine wastes were classified into four source types according to the level of type of waste treatment, [1] windowless pigpen (WP) and [2] open pigpen (OP) (both as raw slurry) and [3] composting facility (CF) and [4] slurry treatment facility (SF) (both as after treatment). Simple emission factors (EF: kg pig-1) assuming a constant emission rate over one year (without decay) were estimated for up to 41 volatile odorants based on the measurement of their flux values from each of all four 100 g waste samples in a 0.75 L impinger with an air change rate of 8 hour-1. The EF (kg pig-1) values of the most dominant species from each source type can be summarized as: (1) WP: NH3 (302) and H2S (10.1), (2) OP: H2S (33.0), NH3 (31.3), and p-cresol (6.16), (3) CF: NH3 (30.1), CH3SH (1.30), and DMS (0.51), and (4) SF: NH3 (168), H2S (14.2), and p-cresol (3.31). Based on these simple EF values, the annual emission of pigpen odorants (mE: t year-1) for 869,290 fattening pigs in South Korea was estimated as 342,500 t y-1 which mainly consisted of NH3 293,300 t (85.6%), H2S 33,100 t (9.7%), and p-cresol 6,390 t (1.9%). However, the actual EF values will be much lower as emission rates decay exponentially over time with the proper considerations for feedstuff nitrogen/sulfur mass balance.