Spatial variability of nitrous oxide and methane emissions from an MBT landfill in operation: Strong N₂O hotspots at the working face

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• 作者：Peter Harborth ; Rol ; Fu? ; Kai M¨¹nnich ; Heinz Flessa ; Klaus Fricke
• 关键词：Nitrous oxide ; Methane ; Landfill gas ; MBT landfill ; GHG emissions ; Gas flux
• 刊名：Waste Management
• 出版年：2013
• 出版时间：October, 2013
• 年：2013
• 卷：33
• 期：10
• 页码：2099-2107
• 全文大小：819 K

文摘

Mechanical biological treatment (MBT) is an effective technique, which removes organic carbon from municipal solid waste (MSW) prior to deposition. Thereby, methane (CH₄) production in the landfill is strongly mitigated. However, direct measurements of greenhouse gas emissions from full-scale MBT landfills have not been conducted so far. Thus, CH₄ and nitrous oxide (N₂O) emissions from a German MBT landfill in operation as well as their concentrations in the landfill gas (LFG) were measured. High N₂O emissions of 20-200 g CO₂ eq. m^?2 h^?1 magnitude (up to 428 mg N m^?2 h^?1) were observed within 20 m of the working face. CH₄ emissions were highest at the landfill zone located at a distance of 30-40 m from the working face, where they reached about 10 g CO₂ eq. m^?2 h^?1. The MBT material in this area has been deposited several weeks earlier. Maximum LFG concentration for N₂O was 24.000 ppmv in material below the emission hotspot. At a depth of 50 cm from the landfill surface a strong negative correlation between N₂O and CH₄ concentrations was observed. From this and from the distribution pattern of extractable ammonium, nitrite, and nitrate it has been concluded that strong N₂O production is associated with nitrification activity and the occurrence of nitrite and nitrate, which is initiated by oxygen input during waste deposition. Therefore, CH₄ mitigation measures, which often employ aeration, could result in a net increase of GHG emissions due to increased N₂O emissions, especially at MBT landfills.