填埋场内渗滤液竖向迁移过程中硫酸盐还原过程的动态演变

Dynamic evolution of sulfate reduction process during vertical migration of leachate in landfill

填埋场内渗滤液的竖向迁移过程重塑物质分布,引发一系列生化反应.本文探究了渗滤液回灌情景下随渗滤液竖向迁移过程的硫酸盐动态还原转化行为.结果表明,受渗滤液竖向迁移影响,硫酸盐(SO42-)还原行为在垂向填埋层间呈显著差异,主要还原产物硫化氢(H2S)和甲硫醚(DMS)均随填埋深度的递增而衰减,说明填埋场恶臭污染防治的主要位点在于浅表层填埋区.渗滤液中SO42-、COD、TOC的消耗量之间存在差别化计量关系.当渗滤液中SO42-浓度高于500 mg·L^(-1)时,COD/SO42-与H2S释放量呈正相关.渗滤液迁移过程中不同填埋层内SO42-还原均不彻底,其连续回灌引起的还原产物持续释放值得深度关注.本研究可为填埋场渗滤液回灌运行过程中的含硫恶臭防治提供科学依据.

The vertical migration of leachate inside landfill site reshapes substance distribution and triggers a series of biochemical reaction.In this research,the dynamic reduction and transformation behavior of sulfate during the leachate vertical migration under leachate recirculation was investigated.It shows that the sulfate(SO42-)reduction behavior differs significantly among vertical landfill layers with the leachate vertical migration.The main reduction products,hydrogen sulfide(H2S)and methionine(DMS),attenuated with increasing landfill depth.The consumption of SO42-,COD and TOC in leachate shows different stoichiometric relationships.When the leachate SO42-concentration is higher than 500 mg·L^(-1),the COD/SO42-ratio is positively correlated with the released H2S amount.In the process of leachate migration,SO42-can’t be completely reduced in all tested landfill layers.The long-term release of SO42-reduction products caused by leachate continuous recirculation needs special attention.This study provides scientific basis for the prevention and control of sulfur-containing odor during the operation of landfill leachate recirculation.