Effects of Coal Fly Ash on Composting Process of Household Garbage

음식쓰레기 퇴비화 과정에서 석탄회 첨가 효과

Because of the high water content of the household garbage, it is difficult to compost it. Therefore, this study was conducted to investigate the possibility of using coal fly ash as humidity conditioner for the household garbage composting. The summarized results are as follows : 1. The maximum temperatures were $35^{\circ}C$ in spring, $47^{\circ}C$ in summer, and $43^{\circ}C$ in winter during the composting periods. 2. The mass was reduced to 70.5% after 60 days. The average volume reduced down to 74.7% after 60 days. 3. The seasonal variation of pH values showed a similar tendency and reached 8.5 after 60 days. 4. The water content was reduced at an early stage of composting and not much changed thereafter. It had 49.7% in spring, 33.9% in summer, and 56.5% in winter after 60 days. Ash contents were not much changed during the composting periods. 5. The contents of inorganic compounds were in the range of $0.06{\sim}4.03%$ $P_2O_5$, $0.01{\sim}2.87%$ CaO, $0.18{\sim}1.43%$ MgO, and $0.39{\sim}2.03%$ $K_2O$. Heavy metal contents were in the range of $ND{\sim}14.08$ Hg ${\mu}g/kg$, $ND{\sim}0.80$ Cd mg/kg, $4.99{\sim}28.95$ Cu mg/kg, $ND{\sim}242.62$ Cr mg/kg, $ND{\sim}20.24$ Pb mg/kg, and $ND{\sim}59.87$ Zn mg/kg.

가정에서 발생되는 음식쓰레기의 높은 수분함량 때문에 원활한 퇴비화가 어렵다. 따라서 본 논문은 가정 쓰레기 퇴비화 수분조절제로서 석탄회의 이용가능성을 알아보고자 하였다. 결과를 요약하면 아래와 같다. 1. 퇴비화기간동안 최고 상승온도는 봄철 $35^{\circ}C$, 여름철 $47^{\circ}C$ 그리고 겨울철 $43^{\circ}C$이었다. 2. 질량은 60일후 70.5% 감소되었으며, 부피는 평균 74.7% 감소되었다. 3. pH의 변화는 3계절 모두 비슷한 경향을 보였으며, 60일 후의 pH는 8.5 였다. 4. 수분함량은 퇴비화 초기에 감소 경향을 보인 후 점차 거의 일정하였다. 60일 후 퇴비의 수함량은 봄철 49.7%, 여름철 33.9%, 겨울철 56.5%였다. 회분함량은 퇴비기간동안은 큰 변화가 없었다. 5. 무기성분 함량은 $P_2O_5$ $0.06{\sim}4.03%$, CaO $0.01{\sim}2.87%$, MgO $0.18{\sim}1.43%$, $K_2O$ $0.39{\sim}2.03%$였다. 각종 중금속 함량은 Hg $ND{\sim}14.08{\mu}g/kg$, Cd $ND{\sim}0.80mg/kg$, Cu $4.99{\sim}28.95mg/kg$, Cr $ND{\sim}242.62mg/kg$, Pb $ND{\sim}20.24mg/kg$, Zn $ND{\sim}59.87mg/kg$이었다.