Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials.
Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials.
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DOI：
10.1016/j.wasman.2010.10.006
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发表时间：
2011-05
期刊：
影响因子：
8.1
通讯作者：
Ingke Rachor;J. Gebert;A. Gröngröft;E. Pfeiffer
中科院分区：
文献类型：
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作者：
Ingke Rachor;J. Gebert;A. Gröngröft;E. Pfeiffer
工程覆盖土壤中甲烷的微生物氧化被认为是减少旧垃圾填埋场或含有低甲烷生成率废物的场地排放的一种有效选择。进行了实验室柱研究，以获得设计标准，使建设一个有效的甲烷氧化覆盖范围内的土壤，可供填埋场运营商。因此，在模拟填埋场条件下，不同土壤的甲烷氧化能力进行了评估。五个桑迪潜在的垃圾填埋场覆盖材料与不同含量的粉土和粘土进行了调查，甲烷氧化和相应的土壤气体成分超过四个月。土壤被压实到其普罗克特密度的95%，导致体积密度为1.4- 1.7 gcm −3，这反映了由于空气填充孔隙减少而导致甲烷氧化的相当不利的条件。将土壤含水量调整为田间持水量，使土壤含水量在16.2 - 48.5vol.%之间。调查的入口通量范围为25至约100 g CH 4 m −2d−1，涵盖了在西欧气候条件下允许填埋场覆盖物完全氧化的甲烷负荷，因此建议将其作为善后处理释放的标准。气体浓度的垂直分布、甲烷通量平衡以及稳定碳同位素研究可以进行清晰的过程识别。较高的进口流量导致的包气带的减少，在绝对甲烷氧化速率的增加和氧化甲烷的相对比例下降。对于每种材料，确定了特定的最大氧化速率，其在20和95 g CH 4 m −2d− 1之间变化，并且与土壤的充气孔隙度呈正相关。甲烷氧化效率和气体剖面数据意味着氧化能力和大气扩散进入之间的密切联系。对于一种具有高水平的细颗粒和高有机物含量的材料，甲烷产生阻碍了甲烷氧化潜力的量化。关于垃圾填埋场覆盖层的设计，得出的结论是，预期甲烷负荷的大小、覆盖材料的质地和预期压实度是需要了解的关键变量。在此基础上，柱研究可以作为一个适当的测试系统，以确定甲烷氧化能力的土壤填埋场覆盖材料。
The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4–1.7gcm−3, reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5vol.%. The investigated inlet fluxes ranged from 25 to about 100g CH4m−2d−1, covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95g CH4m−2d−1and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity and diffusive ingress of atmospheric air. For one material with elevated levels of fine particles and high organic matter content, methane production impeded the quantification of methane oxidation potentials. Regarding the design of landfill cover layers it was concluded that the magnitude of the expected methane load, the texture and expected compaction of the cover material are key variables that need to be known. Based on these, a column study can serve as an appropriate testing system to determine the methane oxidation capacity of a soil intended as landfill cover material.