The Effect of waste Oyster Shell on Anaerobic Composting of Garbage

굴 패각이 음식쓰레기의 혐기성 퇴비화에 미치는 영향

Waste oyster shell was used to study the applicability on anaerobic composting of garbage. Experiment was conducted with five anaerobic reactors. After garbage and compost for inoculation were mixed, waste oyster shell was added into mixed waste in mesophillic temperature for 60 days with 30%, 60% respectively. The amount of produced methane gas, gas composition, organic removal efficiency and pH were measured. Result showed that the amounts of produced gas were 0.62 l /g-VS in R-1, 0.63 l /g-VS in R-2, 0.16 l /g-VS in R-3, 0.75 l /g-VS in R-4, 0.21 l /g-VS in R-5 and the amounts of produced methane gas were 0.32 l /g-VS in R-1, 0.37 l /g-VS in R-2, 0.04 l /g-VS in R-3, 0.42 l /g-VS in R-4, 0.05 l /g-VS in R-5. Proportion of mathane gas which determines the efficiency of anaerobic composting was over 55%. pH were 6.0~8.0 in R-2 and R-4 which contained 30% of waste oyster shell and pH were increased over 8.5 in R-3 and R-5 which contained 60% of waste oyster shell. Since pH were so high and it had a negative effect on microbial growth, anaerobic reaction were not well operated in R-3 and R-5.

본 연구는 $CaCO_3$가 주성분인 굴 패각을 이용하여 혐기성퇴비화 반응시 율속단계의 원인인 pH저하를 감소시킴으로써 혐기성퇴비화에의 굴 패각 적용가능성에 대하여 조사하였다. 실험은 혐기성퇴비화 반응조 5기(R-l~R-5)를 제작하여 음식쓰레기와 접종을 위한 숙성퇴비를 넣은 뒤 굴 패각을 음식쓰레기 주입량에 대해 30%, 60%를 주입하여 중온에서 60일동안 실험하였으며, 메탄가스 발생량, 가스성분비, 유기물제거율 및 pH 등을 측정하였다. 실험결과 가스발생량은 R-1 $0.62{\ell}/g-VS$, R-2 $0.63{\ell}/g-VS$, R-3 $0.16{\ell}/g-VS$, R-4 $0.75{\ell}/g-VS$, R-5 $0.21{\ell}/g-VS$로 나타났으며, 메탄가스 발생량은 R-1 $0.32{\ell}/g-VS$, R-2 $0.37{\ell}/g-VS$, R-3 $0.04{\ell}/g-VS$, R-4 $0.42{\ell}/g-VS$, R-5 $0.05{\ell}/g-VS$로 나타났다. 혐기성퇴비화의 효율을 결정짓는 가스성분비는 R-2, R-4에서의 메탄가스발생량이 전체가스발생량의 55%이상으로 경제성이 있는 것으로 나타났다. pH는 굴 패각을 30% 넣어준 R-2, R-4에서 pH 6.0~8.0을 유지하였으며, 굴 패각을 60% 넣어준 R-3, R-5에서는 pH가 8.5이상으로 상승하여 미생물에 악영향을 미침으로써 혐기성 반응이 제대로 이루어지지 못하였다.