Abstract
This study was carried out to estimate the economic impacts on operation cost and curtail the bulking agent between two kinds of plants in swine farms. Bulking agents and Plants have a variety of roles in the fields of the composting for livestock manure and also represent an economic problem in terms of plant operation costs and compost production. Two farms which have rotary(size of reactor : 10${\times}$35${\times}$1.5m) or bucket(size of reactor : 10${\times}$68${\times}$2m) plants were used for 24 weeks for bucket conveyor system, which are composed of refilling rice hull as a bulking agent every 3 weeks till decreasing volume, for 4 weeks for rotary conveyor system, which has continuous compost production system without refilling rice hull, respectively. Composts was produced in 24 weeks in the bucket conveyor system, in 4 weeks in the rotary conveyor system, respectively. The results are as follows : 1. The tissue change of Rice hull at the composts of 45 days pursuant to composting steps was more crumbling in bucket conveyor system than in rotary conveyor system. 2. Microbial counts of the final composts for safety and quality showed that total bacteria counts was 1.01${\times}$108 cfu/g in bucket conveyor system, 2.82${\times}$108 cfu/g in rotary conveyor system, Salmonella was 0.3${\times}$102 cfu/g in bucket conveyor system, 7.6${\times}$102 cfu/g in rotary conveyor system, colifom bacteria was 0.5${\times}$106 cfu/g in bucket conveyor system, 1.5${\times}$106cfu/g in rotary conveyor system, fungi 1.24${\times}$106 cfu/g in bucket conveyor system, 0.01${\times}$106 cfu/g in rotary conveyor system, respectively. However, Any system used in this trial could not be met the regulation of A grade compost of EPA and USA. 3. C:N ratio according to the composting was more rapidly changed in bucket conveyor system with 64.5 of 5 days compost to 25.4 of final products than in rotary conveyor system with 26.7 of 5 days compost to 25.9 of final products. 4. Based on the mechanical characteristics of plants used in trial and compared with Rotary conveyor system, the Bucket conveyor system in which has 0.72 ㎥/㎥ of bulking agent capacity per slurry could be curtailed 1.78 ㎥of rice hull for disposal of waste, 1㎥. It was proper facilities to produce composts quantitative in Rotary conveyor system, and to treat waste quantitative and obtain good results in compost quality in Bucket conveyor system.
