Methane Emission Reduction Enhanced by Hydrophobic Biochar-Modified Soil Cover

Abstract

The microbial oxidation of CH4 in biochar-modified soil cover is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes full of low CH4 generation rates. The mechanism of methane oxidizing bacteria (MOB) can be enhanced by amending the landfill cover soil with biochar, which is recalcitrant to biological degradation and can adsorb CH4 while facilitating the growth and activity of MOB within its porous structure. However, the increase in the permeability coefficient and water content of the cover due to the addition of biochar also affects the methane removal efficiency. A hydrophobic biochar modified by KH-570 was employed to reduce the water content and to promote the diffusion and oxidation of CH4 in the cover. Several series of small-scale column tests were conducted to quantify the CH4 oxidation properties of the landfill cover soil amended with biochar and hydrophobic biochar under different levels of exposed CH4 concentrations (5% and 15%), heights (10–66 cm), and temperatures (15–40 °C). After 30 days of domestication, the removal rate of the hydrophobic biochar-modified soil cover reached 98.8%. The water holding capacity of the cover and the CH4 oxidation efficiency under different moisture contents were investigated in different columns. The hydrophobic biochar-modified soil cover has a weak water holding capacity, low saturated water content, and optimal CH4 oxidation efficiency at this time.

Mitigation of Methane, NMVOCs and Odor Emissions in Active and Passive Biofiltration Systems at Municipal Solid Waste Landfills

“…Between 110 and 90 cm depth, the biological oxidation was about 30% while between 30 and 10 cm it was about 80%. The trend is comparable with the results found by other authors [31,34,35,49,50]. The overall biowindows CH 4 oxidation efficiency was 88.05 ± 7.9% (n = 20).…”

Industrial biochar systems for atmospheric carbon removal: a review

“…Furthermore, another basic concept is the direct burial of biochar in landfills, as a long-term storage reservoir. The concept of applying biochar to the soil cover of landfills for the mitigation of methane emissions has been investigated in the literature, showing positive results (Wu et al 2020). However, the idea of direct burial of biochar in landfills mainly revolves around the long-term safe storage of sequestered carbon.…”

Processes for Bioenergy and Resources Recovery from Biowaste

“…The Special Issue showcases ten full-length original research articles [13][14][15][16][17][18][19][20][21][22], one short communication [23], and one review article [24] covering different aspects of various processes for bioenergy and resource recovery from biowaste. Specifically, the accepted manuscripts covered a range of essential topics in the areas of anaerobic digestion, microbial fermentation, and thermochemical conversion targeting various value-added resources, including biogas, syngas, bio-oil, and organic acids ( Figure 1).…”