분뇨순환 돈사의 악취특성 및 제거에 관한 연구

Abstract

Analysis results on the odor emission characteristics and causing factors at livestock Wastes circulation system pig houses are as follows; 1. The concentration of complex odors in pig house C applied livestock Wastes circulation system was relatively lower than A, B general pig houses and concentration of Hydrogen sulfide, designated odor, was similar at each pig house which are 0.23 ppm for A, 0.20 ppm for B and 0.19 ppm for pig house C. Hydrogen sulfide was identified as a major contributor to odor at all pig houses in a contribution level test. Concentration of the ammonia at pig house A was 18.0 ppm and it was much higher than pig house B and C which use environmental enhancers 12.9 ppm and 8.5 ppm respectively.

2.The concentration of organic acid as designated odor compounds was surveyed as follows: 0.14 ~ 0.29 ppm for propionic acid, 0.08 ~ 0.18 ppm for butyric acid, 0.02 ~ 0.03 ppm for n-valeric acid and 0.01 ~ 0.04 ppm for I-valeric acid. The concentration of all compounds was much higher in pig house A than pig houses B and C because pig house A did not use environmental enhancers and the organic acid concentration of pig house C was the lowest. There was no significant difference of sulfur compounds between the pig houses caused by usage of environmental enhancers because the concentration of sulfur compounds were identified lower than 0.01 ppm. Organic acid, as well as hydrogen sulfide, was evaluated as a major odor-causing substance, so it must be significantly considered to reduce the odor in the pig house.

3. The concentration of water pollutants was analyzed and the average concentration of pig house A was higher than pig houses B and C. The concentration of s-BOD directly causing the odor at pig house ranged from 228 to 6,510 ㎎/L and was remarkably lower than the concentration of livestock Wastes after six months, which is 12,876 ㎎/L, with changes of pig livestock Wastes components after aeration and stirring (with liquid and solid separation). It confirmed that usage of environmental enhancers could lead to lower odor production and the activated states of microorganism in livestock Wastes could be a major factor in reducing odor production.

4. Measurement results of ammonia and hydrogen sulfide by automatic measuring equipment showed that the emission of above compounds is dependent on the amount of ventilation. The concentration of ammonia and hydrogen sulfide was higher at night than during the day and was concluded that the amount of ventilation is increased during the day than at night so that odor substances were emitted outside. It is concluded that ammonia and hydrogen sulfide at the pig house could be controlled by the amount of ventilation and method and emissions of the two substances are proportional to each other. The temperature and humidity of all three pig houses were surveyed and complied with the feeding and management criteria. The correlation between external and internal temperature and humidity at the pig houses was relatively low because choosing the optimal method of ventilation could buffer the temperature and humidity.

5. The evaluation of odor emission shows that the concentration of most parameter in pig house C was lower than pig house B because they fed additives containing microorganisms to pigs and sprayed it to the slurry pits and livestock Wastes treatment facility while pig house B only used environmental enhancers. The livestock Wastes circulation system in pig houses doesn't produce extra solids so it effectively reduces the odor-causing sources by not making solid-liquid separations and composting facility. Because of improvements on the environment, extra profits will be generated such as decreasing of overcrowded farming, mortality intensity, operation and maintenance costs. This study shows that the effectiveness of treatment at livestock Wastes circulation systems and the usage of microorganisms and the results could be used to develop methods for reducing odors in the pig house and that there is a need to study the specific methods to reduce odors in the pig house.