Molecular-approach Diagnosis of Green gases Emission from landfill sites of Municipal Solid Wastes

在本研究中，我们分析了1)城市固体废物有机有机物组分(OFMSW)在实验室规模的垂直柱中的初始降解过程，模拟了填埋场土层；2)填埋场土壤微生物群落的结构和多样性。制备了4个模拟填埋柱，在不同的条件下考察了氧和水的有效性。OFMSW降解的较早阶段为150天，相当于产酸阶段。在接下来的一段时间内，随着时间的推移，有机物的降解率越来越小，对应于甲烷产生阶段。在此基础上，提出了垃圾填埋场的运行方式：1)提高填埋场上部的好氧条件；2)渗滤液回流。甲烷产率在柱底部(如厌氧部分)最高，而在柱表面(如好氧部分)最低。由此可见，场地的甲烷净产生量应由甲烷氧化菌减去。根据第一年的产气量数据，对填埋场各部分对全球变暖的贡献进行了评估，结果表明，准好氧部分的贡献远高于二氧化碳产生量较大的好氧部位，这一结果表明垃圾填埋场的甲烷净产生量应该减去。被甲烷氧化的细菌。根据第一年的产气量数据，对各柱段对全球变暖的贡献进行了评价，结果表明，准好氧段对全球变暖的贡献远高于好氧段，因为好氧段产生了大量的二氧化碳。

In the present study, we analyzed 1) initial degradation process of organic organic fraction of municipal solid wastes (OFMSW) in the laboratory-scale vertical column, which simulates landfill site soil layers, 2) structure and diversity of the microbial communities of landfill site soil. Four simulated landfill columns were prepared with different conditions with respect to oxygen and water availability. A significant extent of OFMSW degradation occurred during rather earlier stage of 150 days, corresponding to acid-producing phase. During the following period organic degradation becomes less and less with time elapsed, corresponding to methane-producing phase. Based on these observation, we proposed the way of landfill site operation, so as to 1) enhance aerobic condition at the upper portion of landfill site, and 2) recirculate the leachate liquid. Methane production yield was highest in bottom of the columns (e.g., anaerobic part) while it was lowest in surface of the columns (e.g., aerobic part). Thus result suggested that net methane production in the site should be subtracted by methane oxidizing bacteria. Contribution of the each column parts to global warming was evaluated, based on the gas generation data during the first year, and the result showed that contribution of semi aerobic part was much higher compared with that of aerobic site in which significant amount of carbon dioxide was produced.This result suggested that net methane production in the landfill sites should be subtracted. by methane oxidizing' bacteria. Contribution of the each column parts to global warming was evaluated, based on the gas generation data during the first year, and the result showed that contribution of semi aerobic part was much higher compared with that of aerobic part in which significant amount of carbon dioxide was produced.