Role of Landfill Cover Materials in Mitigating GHG. Emissions in Biogeochemical Landfill Cover System

摘要

Municipal solid waste (MSW) landfills are known to be one of the major sources of greenhouse gas (GHG) emissions into the atmosphere. In order to alleviate these emissions, an innovative biogeochemical cover system is proposed to mitigate both methane (CH_4) and carbon dioxide (CO_2) emissions, which are the predominant gases in landfill gas (LFG) emissions. This paper investigates four materials: soil, non-activated biochar, methanotrophic activated biochar, and basic oxygen furnace (BOF) slag for their CH_4 and CO_2 uptake capacity. First, the physical and chemical properties of the four materials were tested. Thereafter, several series of batch tests were conducted to determine CH_4 and CO_2 uptake by each material. The results demonstrate that the soil has the potential to oxidize CH_4 into CO-2 due to presence of CH_4 oxidizing (methanotrophic) bacteria, while the BOF steel slag has potential to sequester CO_2. The methanotrophic activated biochar showed enhanced biological activity due to high methanotrophic population, mitigating CH_4 efficiently. However, the non-activated biochar had little to no effect on the uptake of either CH_4 or CO_2. Finally, the combination of these cover materials at different proportions in different configurations is being investigated to optimize the biogeochemical cover system to mitigate both CH_4 and CO_2 emissions.