有機廢棄物堆積條件對溫室氣體釋出之影響

With the increasing of greenhouse gases in the atmosphere, greenhouse effect has become one of the most important environmental topics. Methane and carbon dioxide will be released to atmosphere during anaerobic digestion in landfill. Column reactor was used to study the effect of moisture content and composition on carbon dioxide and methane emissions during digestion. The initial stage of degradation is aerobic, and large amount of carbon dioxide is produced, then the condition becomes anaerobic and flavors methane production. The maximum carbon dioxide and methane concentrations were 5.0×10^4-1.2×10^5, and 0.8-13 ppm, respectively when the mixture of food wastes and used papers with 4:1 at the initial moisture content 83%. The ratios o f CH_4/CO_2 concentration ranged from 0.12 to 0.60. However, the maximum carbon dioxide and methane concentrations were 1.0×10^5-7.5×10^6, and 6-8 ppm, respectively at initial moisture content 89%. The ratio of CH_4/CO_2 concentration was 0.3. Carbon dioxide emission was significant at the early stage and after turning due to the aerobic condition. The ratio of methane to carbon dioxide indicated the onset of methanogenesis, that started after 24 days of installation. Methane emission increased with the moisture content and organic carbon content of raw materials.