Effect of aerobically treated manure on odorous material emissions from a swine finishing barn equipped with a continuous pit recirculation system

Abstract

This study was conducted to determine reduction of various odorous materials from a swine farm equipped with a continuous pit recirculation system (CPRS) with aerobically treated liquid manure.Methods: CPRS is used in swine farms in South Korea, primarily to improve air quality in pig houses. In this study, CPRS consists of a manure aerobic treatment system and a fit recirculation system; the solid fraction is separated and composted, whereas the aerobically treated liquid fraction (290.0 ± 21.0% per day of total stored swine slurry) is continuously returned to the pit. Four confinement pig barns in three piggery farms were used; two were equipped with CPRS and the other two operated a slurry pit under the slatted floor.Results: All chemical contents of slurry pit manure in the control were greater than those of slurry pit manure in the CRPS treatment (p<0.05). Electrical conductivity and pH contents did not differ among treatments. The biological oxygen demand (BOD) of the slurry pit treatment was greater than that of the other treatments (p<0.05). Total nitrogen, total phosphorus, and ammonia nitrogen contents of the slurry pit treatment were greater than those of other treatments (p<0.05). Odor intensity of the CPRS treatment was lower than that of the control at indoor, exhaust, and outside sampling points (p<0.05). The temperature and carbon dioxide of the CPRS treatment in the pig barn was significantly lower than those of control (p<0.05). All measured odorous material contents of the CPRS group were significantly lower than those of the control group (p<0.05). A c c e p t e d A r t i c l eConclusion: CPRS application in pig farms is considered a good option as it continuously reduces the organic load of animal manure and lowers the average odorant concentration below the threshold of detecting odorous materials.

Seasonal atmospheric characteristics in a swine finishing barn equipped with a continuous pit recirculation system using aerobically treated manure

“…Furthermore, in a previous study, CPRS using aerobically treated liquid swine manure showed a reduction in various odorous materials, such as NH3, H2S, and VOCs [4]. However, in South Korea, because the CPRS system has been operating for a relatively short period, further verification is required.…”

“…We used the same pig finishing confinement building as in the previous study [4] (Table 1, Figure 1).…”

“…The aerated liquid manure is called a "liquid fertilizer" and is commonly stored in a storage tank and then spread in farmlands during the periods specified by the law in South Korea. Finishing pigs were allocated to each experimental barn according to the method of Choi et al (2022) [4]. The average stocking density was 0.92±0.18 m 2 /head (Farm A, 1.00 m 2 /head; Farm B, 1.05 m 2 /head; Farm C, 0.72 m 2 /head).…”

“…The average stocking density was 0.92±0.18 m 2 /head (Farm A, 1.00 m 2 /head; Farm B, 1.05 m 2 /head; Farm C, 0.72 m 2 /head). A fully slatted floor was installed in the barn, with 100 cm deep pits and 600 cm A c c e p t e d A r t i c l e high shanks, and the recirculated aerated liquid manure was sampled in April, August, October, and November for 2 years at 1000 to 1200 h according to the method of Choi et al (2022) [4]. Samples were collected from the storage tank, slurry pit under the swine room, outlet of slurry pit, and anoxic tank using the method described by Choi et al (2022) [4].…”

“…The air inlets were located on the ceiling, and the exhaust ventilation fans were wallmounted (Farm A, four air inlets; Farm B, six air inlets; Farm C, three air inlets). In each room, air samples were collected from central points within the room, downstream and upstream of each continuously operated fan, and outside the room according to the method of Choi et al (2022) [4].…”