上下导气系统对生物反应器压实垃圾中渗滤液和填埋气迁移的影响研究

建立了2组实验室模拟填埋场生物反应器,利用上层和下层同时导排填埋气的方法,研究了填埋气和渗滤液在垃圾体中的产生和迁移情况.并在考虑渗滤液回灌的情况下,设置了C1(渗滤液回灌前加压)、C2(渗滤液回灌后加压)2组对照实验.结果表明,C1在加压后出现短暂的水位雍高现象并在第33 d后消失,而C2一直未出现水位雍高现象,上下同时导气系统能促进渗滤液和填埋气排出,#有效缓解和消除水位雍高.压力促使C1、C2的填埋气由往上迁移转变为往下迁移,C1经历了10 d的填埋气向下迁移准备期,而C2在回灌后填埋气直接往下迁移,回灌会促进孔隙通道打开,有利于气液向下排出.

Gas and leachate migrations with gas collections at the top and bottom of compacted municipal solid waste (MSW) in simulated bioreactors

Two simulated bioreactors were constructed to investigate the effects of compaction and leachate recirculation on leachate and biogas migration. A bioreactor (C1) was compacted before leachate recirculation started. The other (C2) was compacted after leachate recirculation started. Generated biogas from municipal solid waste (MSW) was collected from two ports at the top and the bottom of a bioreactor. Results show that the use of both top and bottom port to collect biogas could effectively facilitate leachate discharge, and reduced the formation of leachate pond on the compacted MSW. With a stress load of 42 kPa in C1, leachate was temporarily increased but lowered with releasing biogas from the bottom port. In C2, the formation of leachate pond was not observed under the same compacted conditions. Leachate recirculation accelerated the decomposition of MSW and increased pore channels in waste, which promoted gas migration. In addition, collecting biogas from the top and the bottom of the compacted MSW increased biogas collection efficiency and reduced leachate levels in the simulated bioreactors.