Sadasivam Bala Yamini, Reddy Krishna R
University of Illinois at Chicago, Department of Civil and Materials Engineering, 842 West Taylor Street, Chicago, IL 60607, USA.
Waste Manag. 2015 Sep;43:218-29. doi: 10.1016/j.wasman.2015.04.025. Epub 2015 May 21.
Mitigation of landfill gas (LFG) is among the critical aspects considered in the design of a landfill cover in order to prevent atmospheric pollution and control global warming. In general, landfill cover soils can partially remove methane (CH4) through microbial oxidation carried out by methanotrophic bacteria present within them. The oxidizing capacity of these landfill cover soils may be improved by adding organic materials, such as biochar, which increase adsorption and promote subsequent or simultaneous oxidation of CH4. In this study, seven wood-derived biochars and granular activated carbon (GAC) were characterized for their CH4 adsorption capacity by conducting batch and small-scale column studies. The effects of influential factors, such as exposed CH4 concentration, moisture content and temperature on CH4 adsorption onto biochars, were determined. The CH4 transport was modeled using a 1-D advection-dispersion equation that accounted for sorption. The effects of LFG inflow rates and moisture content on the combined adsorption and transport properties of biochars were determined. The maximum CH4 adsorption capacity of GAC (3.21mol/kg) was significantly higher than that of the biochars (0.05-0.9mol/kg). The CH4 gas dispersion coefficients for all of the biochars ranged from 1×10(-3) to 3×10(-3)m(2)s(-1). The presence of moisture significantly suppressed the extent of methane adsorption onto the biochars and caused the methane to break through within shorter periods of time. Overall, certain biochar types have a high potential to enhance CH4 adsorption and transport properties when used as a cover material in landfills. However, field-scale studies need to be conducted in order to evaluate the performance of biochar-based cover system under a more dynamic field condition that captures the effect of seasonal and temporal changes.
减少垃圾填埋气（LFG）是垃圾填埋场覆盖层设计中考虑的关键方面之一，以防止大气污染和控制全球变暖。一般来说，垃圾填埋场覆盖层土壤可以通过其中存在的甲烷氧化细菌进行的微生物氧化作用部分去除甲烷（CH4）。通过添加有机材料（如生物炭）可以提高这些垃圾填埋场覆盖层土壤的氧化能力，生物炭可增加吸附并促进CH4的后续或同时氧化。在本研究中，通过进行批量和小规模柱实验，对七种木材衍生的生物炭和颗粒活性炭（GAC）的CH4吸附能力进行了表征。确定了诸如暴露的CH4浓度、水分含量和温度等影响因素对生物炭吸附CH4的影响。使用考虑吸附作用的一维对流扩散方程对CH4传输进行了建模。确定了LFG流入速率和水分含量对生物炭吸附和传输综合性能的影响。GAC的最大CH4吸附容量（3.21mol/kg）显著高于生物炭（0.05 - 0.9mol/kg）。所有生物炭的CH4气体扩散系数范围为1×10(-3)至3×10(-3)m(2)s(-1)。水分的存在显著抑制了生物炭对甲烷的吸附程度，并导致甲烷在更短时间内突破。总体而言，某些类型的生物炭在用作垃圾填埋场覆盖材料时具有增强CH4吸附和传输性能的巨大潜力。然而，需要进行现场规模的研究，以评估基于生物炭的覆盖系统在更动态的现场条件下的性能，该条件能够捕捉季节和时间变化的影响。
