Experimental study of methane oxidation efficiency in three configurations of earthen landfill cover through soil column test

IF 7.1 2区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Waste management Pub Date : 2024-10-10 DOI:10.1016/j.wasman.2024.09.034

H.W. Liu , Y. Huang , S. Feng , S.Q. You , Y. Hong , L.D. Shen

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Abstract

Soil column tests were conducted to investigate methane oxidation efficiency in three configurations of earthen landfill cover under two drying stages separated by an applied rainfall, including the monolithic evapotranspiration (ET) cover, the cover with capillary barrier effect (CCBE) and the three-layer cover. Comprehensive measurements were also documented for water–gas response in soil for analyzing the experimental outcomes. The maximum methane oxidation efficiency of three-layer cover, monolithic ET cover, and CCBE were about 71 %, 62 % and 58 %, respectively. This was because the three-layer cover had the largest oxygen (O₂) concentration in soil above depth of 400 mm, where methane oxidation mainly occurred. This was due to the good airtightness of the bottom hydraulic barrier layer, which led to the lowest air pressure above depth of 400 mm, thereby promoting the entry of atmospheric O₂ into the soil. The monolithic ET cover generally had a larger methane oxidation efficiency than CCBE during the first drying stage by up to 12 %, while the trend reversed overall during the second drying stage, likely due to the enhanced air-tightness of CCBE caused by higher soil water content after rainfall induced by the capillary barrier effects. The methane oxidation efficiency for each landfill cover became lower by up to 30 % during the second drying stage than that during the first drying stage, owing to the higher water content during the second drying stage after rainfall, leading to a larger gas pressure and hence a lower O₂ concentration at shallow soil.

查看原文本刊更多论文

通过土柱试验对三种土质垃圾填埋场覆盖层的甲烷氧化效率进行实验研究。

进行了土柱试验，以研究在两个干燥阶段和一个降雨阶段之间，三种土质垃圾填埋场覆盖层的甲烷氧化效率，包括整体蒸发蒸腾（ET）覆盖层、具有毛细管屏障效应（CCBE）的覆盖层和三层覆盖层。为分析实验结果，还对土壤中的水气反应进行了全面测量。三层覆盖层、单层蒸散发覆盖层和 CCBE 的甲烷氧化效率最大值分别约为 71%、62% 和 58%。这是因为三层覆盖在 400 毫米深度以上的土壤中氧气（O2）浓度最大，而甲烷氧化主要发生在这一深度。这是由于底部水力阻隔层的气密性良好，导致 400 毫米深度以上的气压最低，从而促进大气中的氧气进入土壤。在第一干燥阶段，整体 ET 覆盖层的甲烷氧化效率一般比 CCBE 高，最高可达 12%，而在第二干燥阶段，这一趋势发生了逆转，这可能是由于毛细管屏障效应导致降雨后土壤含水量增加，从而增强了 CCBE 的气密性。在第二干燥阶段，每个垃圾填埋场覆盖层的甲烷氧化效率都比第一干燥阶段低 30%，原因是降雨后第二干燥阶段土壤含水量增加，导致气体压力增大，从而降低了浅层土壤的氧气浓度。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Waste management 环境科学-工程：环境

CiteScore

15.60

自引率

6.20%

发文量

492

审稿时长

39 days

期刊介绍： Waste Management is devoted to the presentation and discussion of information on solid wastes,it covers the entire lifecycle of solid. wastes. Scope: Addresses solid wastes in both industrialized and economically developing countries Covers various types of solid wastes, including: Municipal (e.g., residential, institutional, commercial, light industrial) Agricultural Special (e.g., C and D, healthcare, household hazardous wastes, sewage sludge)