• 한국환경농학회지
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• 제20권4호
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• pp.238-243
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• 2001

본 연구에서는 소형 퇴비화 용기의 최적 조건에서 미생물이나 퇴비화 보조제를 첨가하지 않고 가정에서 발생되는 음식물쓰레기를 매일 1 kg씩 투입하여 퇴비화를 진행하였다. 실험결과를 요약하면 다음과 같다; 퇴비화 진행과정 중 수분함량은 $51.04{\sim}53.45%$로 유지되었다. 질소는 퇴비화 진행과정에서 산화되어 암모니아성 질소 및 아질산성 질소로서 검출되지 않았다. Hemicellulose, Lignin은 시간의 경과에 따라 뚜렷한 경향을 나타내지 않았으나, Cellulose는 점차 감소하는 것으로 나타났다. 중금속의 함량은 Cu, Cd, Pb, Hg, As는 검출되지 않았고 Cr은 $9.8{\sim}13.8$ mg/kg으로 부산물 비료의 기준치 300 mg/kg보다 낮았으며, Zn은 $25{\sim}100$ mg/kg이었다. 무기성분은 $P_2O_5$ $1.32{\sim}1.71%$, CaO $1.29{\sim}1.48%$, MgO $0.41{\sim}0.49%$, $K_2O$ $0.38{\sim}0.74%$로 퇴비화 과정 중 큰 변화가 없었다. 20일 동안 퇴비화한 후 무게 감소율은 습윤 기준 67.5%, 분해율은 48%이었다. 배출된 퇴비의 숙성도는 3등급이었다.

• Journal of Biosystems Engineering
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• 제36권3호
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• pp.217-222
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• 2011

This study was carried out in order to reduce the amount of underground water which is used in the double layered single span plastic greenhouse for retaining heat. For this research, two plastic green houses of the double layered single span plastic greenhouse were installed. There was equipped of internal small tunnel for keeping warm air in the interior of the house. Then the internal small tunnel for keeping warm air was fitted with PVC duct of 50 cm in diameter filled with subsurface water. The surplus solar energy in the greenhouse was stored in the water in the PVC duct. Four FCUs (Fan Coil Unit), which has the capacity of 8,000 kcal per hour, were installed in the middle of the house, and a circulation motor in heat storage water tank was operated from 10:30 a.m. to 16:00 p.m. in order to circulate water between the water tank and the FCUs. Consequently about 5 degrees celsius could be maintained in the interior of the internal small tunnel for keeping warm air with the external temperature of lower than minus 5 degrees celsius. It appeared that the alteration of an internal temperature of the house was flexible depending on the sunlight during daytime. To prevent the water freezing, mixing antifreezing liquid in the water or operating FCU continuously was needed. Also, in order to use the surplus solar thermal energy on plastic green house of water curtain system efficiently, storing the surplus heat during daytime simultaneously finding a method of using water curtain systematic underground water happened to be important. As a result of this research, when the house's interior temperature is below zero the operation of FCU appeared to be impossible. Considering the amount of water used in the house with water-curtain-heating system is 150~200 ton per day, using the system mentioned in this research showed that reducing the underground water more than 80% in order to maintain the internal temperature as the level of 5 degree celsius at the extreme temperature of minus 5 degrees celsius.