In the present study, we evaluated the effect of pH modulation on concentrations of odorous compounds and pollutants in pit slurry from pig operation building. A slurry sample was taken from the pit of a pig operation building where 50 finishing pigs [(Landrase × Yorkshire) × Duroc] were kept. Three levels of pH (6, 8 and 10) were measured and adjusted daily during the incubation periods using chemical reagents of 1 N HCl or 3 N NaOH. Concentrations of odorous compounds and pollutants were analyzed from slurry incubated for 7 days. When these material concentrations were compared with the pH 8 slurry which was the pH of pit slurry, levels of short chain fatty acids, indoles and total organic carbon were reduced 7%, 68% and 2%, respectively, in the pH 6 treatment (P<0.05). Ammonium nitrogen, phenols and total nitrogen concentrations were lower by 31%, 18% and 17%, respectively, than with the pH 10 slurry (P<0.05). When the odor contribution in pH treatments was assessed according to the odor activity value, it was found to be 23% lower in the pH 6 treatment compared with pH 8. The pH modulation would affect odor emissions and microbial activity from pit slurry. Although not all odorous compounds showed the reduction effect with the same pH control, this study can be effectively used as base data when using additives for pH control.

The principal hygienic problem caused by livestock industry is the odor exposed to farm workers. This study was performed to assess air cleaner efficiency for reducing odor through on-site evaluation. The concentration of ammonia and hydrogen sulfide, which are major odorous compounds generated from livestock building, were monitored by realtime direct recorder. The odor mixture was measured by air dilution method applying human noses of five panels. Their reduction efficiencies were represented by difference between initial concentration exhausted by non-treatment and concentration measured after treatment of respective control mechanism (water, germicide and plasma ion) of air cleaner. Mean levels of ammonia and hydrogen sulfide were 1.84 (SD:0.22) ppm and 76.83 (SD:1.37) ppb for non-treatment, 1.23 (SD:0.09) ppm and 59.07 (SD:2.68) ppb for wet scrubber (water), 1.08 (SD:0.03) ppm and 58.55 (SD:1.62) ppb for wet scrubber (germicide), and 0.96 (SD:0.03) ppm and 53.66 (SD:1.37) ppb for plasma ion, respectively. Mean dilution factors of odor mixture were 100 for non-treatment, 66.9 for wet scrubber (water), 144.2 for wet scrubber (germicide), and 66.94 for plasma ion, respectively. Based on the results obtained from on-site evaluation, ammonia and hydrogen sulfide showed the mean reduction efficiency of 40% and 25.7% compared with non-treatment process of air cleaner, respectively. In the case of odor mixture, the highest dilution factor was observed at wet scrubber (germicide) compared with other control mechanism of air cleaner.

An objectives of this study is to investigate indoor concentrations of 22 odorous compounds, which are regulated by the domestic act, emitted from pig buildings through on-site visit per month from July, 2011 to June, 2012. Of 22 odorous compounds, the highest concentration was found in ammonia with ppm unit, followed by hydrogen sulfide, methyl ethyl ketone, propionic acid and butylic acid with ppb unit of approximate hundred level. The other odorous compounds were detected below ppb unit of approximate ten level. A remarkable finding is that there is no pig building which showed the airborne levels of five aldehyde-based odorous compounds (acetaldehyde, propionaldehyde, butyraldehyde, n-valeraldehyde and i-valeraldehyde). In general, indoor concentrations of odorous compounds in pig buildings were higher in scraper type than slurry type based on pig manure collection system and higher in enclosed type than winch-curtain type based on ventilation mode, respectively. In temporal distribution of odorous compounds, their concentrations in summer season (June to August) when ventilation rate in pig building decreased relatively were generally higher than those in winter season (December to February) when ventilation rate in pig building is relatively high. The seasons of spring (March to May) and autumn (September to November) showed middle levels of odorous compounds between summer and winter.

The purpose of this study is to investigate concentration and emission coefficients of 22 odorous compounds, which are regulated by the domestic act, emitted from pig buildings by on-site survey. The odorous compounds which were detected in at least one pig building were ammonia, hydrogen sulfide, methyl mercaptan, dimethyl sulfide, dimethyl disulfide, trimethyl amine, stylene, toluene, xylene and methyl ethyl ketone whereas other 12 odorous compounds were not detected in pig buildings. In general, indoor concentrations of odorous compounds in pig buildings were higher in scraper type than slurry type based on pig manure collection system and higher in enclosed type than winch-curtain type based on ventilation mode, respectively. In monthly distribution of odorous compounds, their concentrations in September and October when ventilation rate in pig building decreased relatively were generally higher than those in July and August when ventilation rate in pig building is relatively high. On the contrary, the emission coefficients of odorous compounds in pig building were generally higher in July and August than September and October. The levels of emission coefficients of odorous compounds obtained from this study were similar or slightly higher compared to those reported previously from foreign countries.

The objective of this study is to quantify the levels of airborne bacteria in pig building according to pig housing type. Mean concentration of airborne bacteria in the housing room of gestation/farrowing pigs were 3,690(±1,528)cfu m^-3 in spring, 10,145(±4,266)cfu m^-3 in summer, 1,546(±835)cfu m^-3 in autumn, and 2,582(±916)cfu m^-3 in winter, respectively. Mean concentrations of airborne bacteria in the housing room of nursery pigs were 11,628(±5,624)cfu m^-3 in spring, 36,054(±13,260)cfu m^-3 in summer, 2,743(±1,688)cfu m^-3 in autumn, and 4,075(±2,300)cfu m^-3 in winter, respectively. Mean concentrations of airborne bacteria in the housing room of growing/fattening pigs were 34,025(±8,652)cfu m^-3 in spring, 36,619(±10,234)cfu m^-3 in summer, 10,230(±3,521)cfu m^-3 in autumn, and 26,208(±5,248)cfu m^-3 in winter, respectively. As a result, mean concentrations of airborne bacteria in terms of pig housing type were highest in growing/fattening housing room followed by nursery housing room and gestation/farrowing housing room (p<0.05). The pig building showed the highest levels of airborne bacteria in summer followed by spring, winter and autumn (p>0.05). Overall airborne bacteria which have particle size over 2.1㎛ (stage 1~stage 4) accounted for approximately 80% compared to total airborne bacteria regardless of pig housing type. The predominant airborne bacteria in pig building were Micrococcus spp., Brevibacillus spp. and G(+) Bacillus.