回灌渗滤液VFA浓度对填埋层甲烷化代谢的影响

Impact of VFA Concentration of Recirculated Leachate on Stabilized Methanogenetic Landfill Layer

处于稳定产甲烷阶段的填埋层具有降解回灌渗滤液有机物的能力,但高浓度渗滤液的主要组分(挥发性脂肪酸(VFA))可能影响填埋层的甲烷化代谢,导致填埋层对回灌渗滤液有机物降解效率恶化.采用实验室模拟填埋柱回灌不同ρ(VFA)模拟渗滤液的方法,研究不同VFA负荷对稳定产甲烷阶段填埋层甲烷化代谢的影响.结果表明:稳定产甲烷填埋层具有处理高ρ(VFA-C)渗滤液的能力,其有机碳的转化能力小于1.0 g/(kg.d);当回灌渗滤液中的ρ(VFA-C)大于14.8 g/L(有机负荷为2.2 g/(kg.d))时可抑制填埋层的甲烷化代谢,但这种抑制可随着回灌渗滤液中ρ(VFA-C)的降低而得到解除;为保证填埋层内垃圾的降解,应控制回灌渗滤液的有机负荷不超过1.0 g/(kg.d).

Organic matters in recirculated leachate could be treated by the stabilized methanogenetic landfill layer. However, high content of volatile fatty acids （VFA） in the recirculated leachate could inhibit the methanogenesis in the landfill layer, and reduce its removal efficiency for organics. Lab-scale stabilized methanogenetie landfill column, recirculated with simulated leachate, was setup and the effect of VFA mass concentration of recireulated leaehate on the methanogenesis of bioreactor landfill layer studied. The results indicate that leaehate with high VFA- C mass concentration could be treated by the methanogenetic landfill layer, whose capacity less than 1.0 g/（kg· d）. Methanogenesis is inhibited when the VFA-C mass concentration of recirculated more than 14.8 g/L, with the organic loading of 2.2 g/（kg·d）. However, the inhibition could be eliminated when the VFA-C mass concentration drops to 12.0 g/L. For the purpose of maintaining the waste degradation in the stabilized methanogenetic landfill layer, the VFA- C concentration of recirculated leachate should be less than 1.0 g/（ kg· d）.