垃圾填埋场新型覆盖层材料厚度对甲烷氧化行为的影响

甲烷是一种长期存在于大气中的重要温室气体,它对温室效应的贡献率是二氧化碳的21倍,生活垃圾填埋场是仅次于水稻田的第二大甲烷人为排放源,减少垃圾填埋场的甲烷气体排放对缓解全球变暖压力具有重要意义.在实验室条件下模拟垃圾填埋场甲烷排放情况,将堆肥+陶粒混合物(体积比1:1)这一新型覆盖层材料按6个厚度(30、40、50、60、70、80 cm)装入有机玻璃柱中研究甲烷氧化与覆盖层深度的关系.研究结果表明:试验94 d甲烷氧化率开始下降,到实验结束前6个柱体中甲烷氧化率相似,维持在24.6%～34.8%之间;甲烷氧化速率由于甲烷通入量不断加大呈现先增加后减小的趋势,最低值为2.45 mol·m~(-2)·d~(-1),最高值为17.82 mol·m~(-2)·d~(-1);在试验第119～121d对各个柱体不同深度的气体成分进行分析.发现甲烷氧化的范围主要集中在基质0cm～30cm深处.

Effects of thickness of new landfill cover material on the methane oxidation

Methane is a one of key greenhouse gases. Landfill is the second-largest source of anthropogenic methane emissions followin the rice field. Reducing the emission of methane in landfill has great significance for mitigating global warming. In this paper, the relationship between methane oxidation and landfill thickness was studied with 6 simulated columns.which were filled with a mixture of ceramsite and compost(50 vol %of compost and 50 vol% of ceramsite). The result show the methane oxidation efficiency decreased at the 94th day of the experiment. At the end of the experiment, the oxidation efficiency in 6 simulated columns was similar, varying between 24.6% and 34.8%. With the increase of methane input, the oxidation velocity of methane increased firstly and decreased thereafter, with the minimum value of 2.45 mol·m~(-2)·d~(-1) and the maximum value of 17.82 mol·m~(-2)·d~(-1). The most intensive methane oxidation occured at the layer of 0～30 cm, based on the analysis of gas composition at the different depths of 6 columns within 119 and 121 day's experiment..