Old landfills require pre‐aeration before excavation to reduce the emissions of volatile organic compounds and methane. Variation and distribution of gas species during landfill aeration is important in designing an aeration system and evaluating aeration progress. Limited research is conducted on the variation of gas concentration in aerobic landfills considering methane oxidation and aerobic waste degradation. In this study, a numerical model is developed considering reactions to simulate the changes in methane, oxygen, and carbon dioxide concentrations in landfills during air injection and extraction. Parameter sensitivity analyses are conducted to evaluate the effects of permeability, dispersion coefficient, maximum methane oxidation rate, and oxygen consumption rate on simulation results. Results show that the model is sensitive to oxygen consumption rate. Overall, the application of this model in aerobic landfills provides a practical method to predict gas concentration variation. This model can be used in the optimal design of in situ aeration system.

中文翻译：

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模拟垃圾填埋场注气和抽气过程中的气体浓度

旧的垃圾填埋场在开挖前需要进行预曝气，以减少挥发性有机化合物和甲烷的排放。垃圾填埋场曝气过程中气体种类的变化和分布对于设计曝气系统和评估曝气进度至关重要。考虑到甲烷氧化和需氧废物降解，对需氧垃圾填埋场中气体浓度的变化进行了有限的研究。在这项研究中，开发了一个考虑反应的数值模型，以模拟空气注入和抽出过程中垃圾填埋场中甲烷，氧气和二氧化碳浓度的变化。进行参数敏感性分析以评估渗透率，弥散系数，最大甲烷氧化速率和耗氧速率对模拟结果的影响。结果表明该模型对耗氧率敏感。总体而言，该模型在好氧填埋场中的应用提供了一种预测气体浓度变化的实用方法。该模型可用于原位曝气系统的优化设计。