Effects of Biochar on Methane Oxidation and Properties of Landfill Cover Soil: Long-Term Column Incubation Tests
Effects of Biochar on Methane Oxidation and Properties of Landfill Cover Soil: Long-Term Column Incubation Tests
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DOI：
10.1061/(asce)ee.1943-7870.0001829
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发表时间：
2021-01-01
影响因子：
2.2
通讯作者：
Chetri, Jyoti K.
中科院分区：
文献类型：
--
作者：
Reddy, Krishna R.;Yargicoglu, Erin N.;Chetri, Jyoti K.
垃圾填埋气对全球气候变化构成重大风险。垃圾填埋气是由非常高浓度的甲烷(CH4)组成的，按体积计算接近50%。本研究通过长期土柱培养试验，研究了生物炭改良剂在粉质粘土填埋场覆盖土中作为减少CH4排放的一种手段。在柱子试验中评估了2%和10%(按重量计)生物炭改良土壤的改良率；根据以前的文献综述，改良剂要么应用于预计甲烷氧化活性最高的区域[表层以下0.20-0.40米(20-40厘米)]，要么应用于整个土层[表层以下0-0.60米(0-60厘米)]。柱子在模拟垃圾填埋场覆盖条件下孵化，在底部使用合成垃圾填埋气(60%CH4和40%二氧化碳)，并在顶空空气冲洗400天。对覆盖基材的初始和最终物理化学性质进行了评估，以将CH4的去除效率和长期性能与关键的覆盖层性能相关联。在整个试验过程中，观察到添加生物炭增加了土壤孔隙度、持水能力、水力传导性和土壤总湿度。在所有试验阶段中，生物炭改良剂用量最大(10%)的土柱对CH4的平均去除效率也最高[CH4负荷约为0.05-0.2 kg m(-2)天(-1)(50-200 g m(-2)天(-1)])。所有被测试的设计在测试的甲烷负荷下都显示出相对较高的甲烷去除效率(>；90%)。研究结果表明，添加生物炭可以改善土壤覆盖物对CH4氧化的长期强化性能，这可能有助于减少水分损失，减少实际填埋场覆盖物中的干燥开裂和逃逸排放。(C)2020年美国土木工程师学会。
Landfill gas poses significant risk to global climate change. Landfill gas is composed of very high concentrations of methane (CH4), nearly 50% by volume. The present study investigates the use of biochar amendment to silty clay landfill cover soil as a means of reducing CH4 emissions via long-term soil column incubation experiments. Amendment ratios of 2% and 10% (by weight) biochar-amended soil were evaluated in column tests; amendments were either applied to the zone in which CH4 oxidation activity was expected to be highest based on previous literature reviews [0.20-0.40 m (20-40 cm) below the surface] or throughout the entire soil layer [0-0.60 m (0-60 cm) below the surface]. Columns were incubated under simulated landfill cover conditions by applying synthetic landfill gas (60% CH4 and 40% CO2) at the base and atmospheric air flushing the headspace for >400 days. Initial and terminal physicochemical properties of the cover substrates were assessed to relate CH4 removal efficiency and long-term performance to key cover properties. An increase in soil porosity, water holding capacity, hydraulic conductivity, and overall soil moisture throughout testing was observed with biochar addition. The soil column with the greatest amount of biochar amendment (10% by weight) also had the highest average CH4 removal efficiency across all test stages [CH4 loads of approximately 0.05-0.2 kg m(-2) day(-1) (50-200 g m(-2) day(-1))]. All tested designs displayed relatively high CH4 removal efficiencies (>90%) at the CH4 loads tested. The study results suggest that the long-term performance of soil covers for enhanced CH4 oxidation may be improved by the addition of biochar, which may help to reduce moisture loss and minimize desiccation cracking and fugitive emissions in actual landfill covers. (C) 2020 American Society of Civil Engineers.