Succession Of Bacterial And Archaeal Community Structure During The Simulated Process Of Landfill Stabilization

In China,landfilling is major disposal way for municipal solid waste?MSW?.MSW is gradually decomposed and landfill is going to reach to stable state.Microbial community play vital role in MSW decomposition.However,little is known about the microbial community dynamics along refuse decomposition process and how environmental parameters impact the community.Study on succession of microbial community structure along the stabilization process of landfill is helpful to understand the degradation mechanism of refuse and provides the theoretical basic for the next generation bioreactor landfill.In this study,the stabilization process of landfill was simulated in laboratory by leachate recirculation and the related physiochemical parameters of refuse and leachate was monitored.Physical and chemical parameters of the refuse and leachate divided the stabilization process into three typical phases?aerobic phase,anaerobic acid phase,and methanogenic phase?.High throughout MiSeq sequencing was used to analysis the bacterial and archaeal community structure in refuse and leachate along landfill stabilization process.The main conclusions are as follows:?1?In the process of landfill stabilization,the bacterial community of refuse and leachate are mainly composed of Bacteroidetes,Firmicutes and Proteobacteria,accounting for>90%relative abundance of total community.Along aerobic phase,anaerobic acid phase and methanogenic phase,the relative abundance of Bacteroidetes in refuse has increased gradually,Proteobacteria has decreased firstly and then increased,but Firmicutes has decreased firstly and then increased.On the other hand,the relative abundance of Bacteroidetes in leachate has increased and then decreased,both the Proteobacteria and the Firmicutes have decreased firstly and then increased.Bacterial community structure at the genus level in refuse and leachate in each phase has its own characteristics.Multivariate analysis showed that nitrate and five-day biochemical oxygen demand?BOD₅?are the main factors affecting the bacterial community structure of leachate,however,TP,nitrate and BOD₅ are the main factors affecting the bacterial community structure of refuse.?2?In the process of landfill stabilization,the archaeal community of refuse and leachate are mainly composed of Methanomicrobiales,Methanosarcinales and E2.Along aerobic phase,anaerobic acid phase and methanogenic phase,the methanogenic community in refuse has been dominated by hydrogenotrophic Methanofollis?56.71%?at first,then dominated by acetotrophic Methanosarcina?18.99%?and hydrogenotrophic Methanofollis?13.22%?together,and by hydrogenotrophic Methanocorpusculum?61.26%?at last;however,the methanogenic archaea in leachate is always dominated by hydrogenotrophic methanogens,which has gradually shifted from Methanoculleus?32.34%?to Methanocorpusculum?85.92%?.Multivariate analysis has showed that BOD₅and pH are the main factors affecting the archaeal community structure of leachate,but BOD₅,and nitrate are the main factors affecting the structure of the archaeal community of refuse.?3?BOD₅ significantly affects the bacterial and archaeal community structure in refuse and leachate.