Relevance of soil physical properties for the microbial oxidation of methane in landfill covers
Relevance of soil physical properties for the microbial oxidation of methane in landfill covers
复制标题
DOI：
10.1016/j.soilbio.2010.07.004
复制
发表时间：
2011-09-01
影响因子：
9.7
通讯作者：
Pfeiffer, Eva-Maria
中科院分区：
文献类型：
--
作者：
Gebert, Julia;Groengroeft, Alexander;Pfeiffer, Eva-Maria
填埋场覆盖土壤中甲烷的微生物氧化为减少填埋场甲烷排放提供了巨大的潜力。高甲烷降解率只能实现，如果大气中的氧气供应的甲烷营养群落是足够的。因此，如果环境变量，如pH值或营养状态是不受限制的，系统性能建议由可用于气体输送的孔的份额。扩散试验以及柱的研究进行了调查充气孔隙率和压实度的扩散率和甲烷氧化效率的影响。结果表明，有效扩散系数控制氧气通过土壤迁移是指数相关的充满空气的孔隙空间，并可以显着降低压实。孔隙系统的不连续性和曲折性强烈阻碍了空气填充孔隙度低于10%的扩散迁移。在柱研究中，土壤气体成分和甲烷氧化速率与压实度和平流底层通量的大小相关。低通气，因此低甲烷氧化率在高压实率和/或高底部通量，而高速率可以保持在较低的通量和/或低压实率。在低压实度（普罗克特密度的75%）下，3.5 g CH 4 m（-2）h（-1）的通量可以在任何时候被桑迪壤土完全氧化，在实验期间没有达到其容量极限。我们的研究表明，用于甲烷氧化生物覆盖物的土壤应保持至少14体积%的空气填充孔隙率。在低和中等压实度下，这是由砂、壤质砂、桑迪壤土和一些粗结构壤土提供的。(C)2010爱思唯尔有限公司版权所有。
The microbial oxidation of methane in landfill cover soils offers great potential to reduce methane emissions from landfills. High methane degradation rates can only be accomplished if the supply of atmospheric oxygen to the methanotrophic community is adequate. Thus, if environmental variables such as pH or nutrient status are not limiting, system performance is suggested to be governed by the share of pores available for gas transport. Diffusion tests as well as column studies were conducted to investigate the effect of air-filled porosity and degree of compaction on diffusivity and methane oxidation efficiency. Results show that the effective diffusion coefficient governing oxygen migration through soil is exponentially related to air-filled porosity space and can be significantly decreased by compaction. Discontinuity and tortuosity of the pore system strongly impeded diffusive migration at air-filled porosities below 10%. In the column study, soil gas composition and methane oxidation rates correlated with both the degree of compaction and the magnitude of advective bottom flux. Low aeration and hence low methane oxidation rates prevailed at high compaction rates and/or high bottom fluxes whereas high rates could be maintained at lower fluxes and/or low compaction rates. At a low degree of compaction (75% of the Proctor density), fluxes of 3.5 g CH4 m(-2) h(-1) could be fully oxidized at all times by a sandy loam, the capacity limit of which was not reached during the experiment. Our studies suggest that soils intended for use as methane-oxidizing biocovers are to maintain an air-filled porosity of at least 14 vol.%. At low and medium degree of compaction, this is provided by sands, loamy sands, sandy loams and some of the coarsely textured loams. (C) 2010 Elsevier Ltd. All rights reserved.