模拟生物反应器加速产甲烷过程研究

渗滤液原液回灌易导致填埋垃圾产甲烷过程的滞后,从而对甲烷收集利用产生不利影响。通过3根实验室模拟生物反应器,研究了原液回灌(C1)、渗滤液好氧预处理后回灌(C2)和原液回灌+垃圾层上部通风曝气(C3)3种填埋方式下的填埋气产气规律。结果表明,C1甲烷浓度经历短暂上升,达到19.5%后开始逐渐降低,产甲烷速率和产甲烷总量均很低;C2甲烷浓度逐渐上升,在第121天时甲烷浓度达到50%,产甲烷最高速率和产甲烷总量分别为0.31 L/(kg·d)和25.2 L/kg。在停止上部垃圾层通风曝气后,C3甲烷浓度迅速上升,在81 d时甲烷浓度便达到50%以上,最大产甲烷速率和产甲烷总量分别为0.22 L/(kg·d)和16.0 L/kg。对各模拟柱填埋气可回收性评价结果表明,C3填埋气可回收利用比例最高,C2略低,C1在实验期间内则无可回收利用气体产生。

Acceleration of methane production in bioreactor landfills

Recirculation of raw leachate could result in inhibition of methane production in landfills.Three laboratory-scale columns C1,C2,and C3 were constructed to simulate landfill bioreactors under different operation conditions,including raw leachate recirculation,landfill bioreactor with aerobic pretreated leachate recirculation,and landfill bioreactor with aeration at the upper layer,respectively.Results showed that methane concentration in C1 decreased gradually after peaking (19.5%) on the 43rd day,and methane generation rate,as well as cumulative methane generation,was insignificant throughout the experiment.Methane concentration in C2 gradually increased to 50% on the 121st day,and the highest methane generation rate was 0.31 L/(kg·d).At the end of the experiment,the cumulative methane generation in C2 was 25.2 L/kg.Methane concentration in C3 increased quickly,arriving at 50% within 9 days after aeration ceased.The highest methane generation rate and the cumulative methane generation in C3 were 0.22 L/(kg·d) and 16.0 L/kg.Furthermore,analysis of landfill gas amount with different methane concentration levels showed that,gas collected in C3 had the highest energy utilization potential,followed by gas collected in C2,while gas collected in C1 during experiment was not suitable for energy utilization.