Abstract：
Biochar amendment for landfill soil cover has the potential to enhance methane removal efficiency while minimizing the soil depth. However, there is a lack of information on the response of biochar-mediated soil cover to the changes in configuration and operational parameters during the methane transport and transformation processes. This study constructed three biochar-amended landfill soil covers, with reduced soil depths from 75 cm (C2) to 55 cm (C3) and 45 cm (C4), and the control group (C1) with 75 cm and no biochar. Two operation phases were conducted under two soil moisture contents and three inlet methane fluxes in each phase. The methane removal efficiency increased for all columns along with the increase in methane flux. However, increasing moisture content from 10% to 20% negatively influenced the methane removal efficiency due to mass transfer limitation when at a low inlet methane flux, especially for C1; while this adverse effect could be alleviated by a high flux. Except for the condition with low moisture content and flux combination, C3 showed comparable methane removal efficiency to C2, both dominating over C1. As for C4 with only 45 cm, a high moisture content combined with a high methane flux enabled its methane removal efficiency to be competitive with other soil depths. In addition to the geotechnical reasons for gas transport processes, the evolution in methanotroph community structure (mainly type I methanotrophs) induced by biochar amendment and variations in soil properties supplemented the biological reasons for the varying methane removal efficiencies.
摘要：
用于垃圾填埋场土壤覆盖的生物炭改良剂有可能提高甲烷去除效率，同时最大程度地减少土壤深度。然而,缺乏有关生物炭介导的土壤覆盖对甲烷运输和转化过程中配置和操作参数变化的响应的信息。本研究构建了三个生物炭改良的垃圾填埋场土壤覆盖层，土壤深度从75厘米（C2）减少到55厘米（C3）和45厘米（C4），和对照组（C1），75厘米，不含生物炭。在两个土壤水分含量和每个阶段的三个入口甲烷通量下进行了两个操作阶段。所有塔的甲烷去除效率随着甲烷通量的增加而增加。然而,在低入口甲烷通量时，由于传质限制，水分含量从10%增加到20%对甲烷去除效率产生负面影响。特别是对于C1;而这种不利影响可以通过高通量来缓解。除低含水率和焊剂组合条件外,C3显示出与C2相当的甲烷去除效率，两者均超过C1。至于只有45厘米的C4，高水分含量和高甲烷通量使其甲烷去除效率与其他土壤深度具有竞争力。除了气体运输过程的岩土原因外，生物炭修饰引起的甲烷菌群落结构（主要是I型甲烷菌）的演化和土壤特性的变化补充了甲烷去除效率变化的生物学原因。
