Characteristics Of Metal Ions And Microbial Community Structure In Different Stages Of Landfill Leachate Treatment

With the development of the economy,with more and more domestic waste,the"two pollutants"leachate is inevitable in the process of waste treatment,and the treatment of landfill leachate has been the focus and difficulty of environmental treatment at home and abroad.Based on the treatment process of the landfill leachate treatment plant in Jiangcun gully,Xi'an,this paper uses inductively coupled plasma emission spectrometer?ICP?to detect and analyze the contents and changes of the metal ions in the leachate liquid,the effluent of the regulating pool,the biochemical effluent and the concentrated liquid in the leachate treatment plantand analyze the changes of metal ions in the leachate.The microgenome sequencing technology was used to detect the microbial communities in the four stages of leachate and to analyze and compare the dominant strains in the leachate and their microbial community structure in different stages.The aim of this study was to explore the effects of heavy metals on the biological treatment of landfill leachate and put forward the utilization of humus in the concentrated solution.Suggestions.Finally,the following main results are obtained:?1?Water in different stages of Landfill Leachate has19 kinds of metal ionswhich containing 5 kinds of conventional metal ions,14 kinds of heavy metal ions,and 5 kinds of heavy metal ions?Zn,Pb,Ni,Cr,Cu?are included in the list of priority pollution control of the Ministry of environmental protection.?2?During the leachate solution is placed in the regulating poolfor 40 days,the concentration changes of the 19 metal ions have a rise and fall,and the variation range is not consistent;there are 16 kinds of metal ion concentration rising from the effluent of the regulating pool to the biochemical pond,and the highest(Ca²⁺)increased by 217.74%and only 3,from the biochemical effluent to the concentration solution and the concentration of metal ions.There were 15 kinds of reduction,the maximum(Ca²⁺)decreased by 91.87%,and the increase was only 4.?3?During the original liquid to the regulating pool,the contents of various heavy metal ions are not consistent.The main influencing factors may include the difference of microbial growth and utilization,the degree of biological adsorption and analysis,the variation of acidity and alkalinity in the precipitation or dissolving degree,and the spatial and temporal heterogeneity of the landfill waste.?4?From the regulating pool to the effluent stage of biochemical treatment,the content of heavy metals in cationic heavy metals and oxygen ions all showed an increasing trend,and the increase of each metal ion was greatly different.The reason may be that the leachate studied by the UASB anaerobic pool and MBR treatment unit,the biochemical treatment tail section is mainly humus treatment,humus biological treatment process may destroy the humus metal ions bonding,thus increasing the content of heavy metals in water.?5?From the stage of biochemical effluent to concentrating liquid,the content of heavy metals in cation heavy metals and oxygen ions showed a decreasing trend,and the difference of each metal ion decreased greatly.The leachate treatment plant has been treated by UASB+MBR process.Biological treatment has entered the late stage of endogenous respiration.Heavy metals enter the liquid phase with the decay of microbes.Considering the treatment process of the treatment plant,some heavy metal ions are transferred from liquid to solid sludge after biochemical treatment.The metal ions are decreasing.?6?It was found to be 12,8,11 and 12 species of known bacteriainthefour samples,and all of which contain a large number of unclassified strains.Pseudomonas is the dominant genus in No.1 and 2.There are 29 species in this genus,including Pseudomonas aeruginosa,Pseudomonas fluorescens and Pseudomonas maloda to animals or humans.The disease was almost eliminated in biochemical water,indicating that the biochemical treatment stage had a good removal effect on the pathogen.?7?Ottowia is the dominant bacterial genus in biochemical effluent,and Thauera and Nitrosomonas account for 6.06%and 5%of the total bacteria,and soxobia is also called aerobic denitrifying bacteria.Before the biochemical stage,the contents of the genus Salmonella and nitrite are almost no,both are the dominant functional bacteria in the biochemical treatment stage,and the biochemical treatment stage can be made more effectively by artificial control of the conditions required for survival.?8?Issatchenkia is the dominant fungal genus in the leachate solution.Phlebiopsis accounts for 28.49%of the total number of fungi in the effluent of the regulating pool.It is the dominant genus in the regulating pool,which is about 400%in the leachate liquid,and20.82%of the total fungi,Issatchenkia6.39%,the decrease of 9.89%,fungi algae unclassified Incertae sedis,accounting for 2.96%of the total fungi,reduced by 1.61%;the percentage of the remaining fungi are less than 4%.?9?Put forward the proposal of the solution for the concentrated solution of the leachate treatment plant:before the regulating pool,before the biochemical treatment,the heavy metal is pretreated with the adsorption method,which can reduce the heavy metal ions into the liquid and solid phase of the concentrated liquid in advance,so that it can meet the conditions of the resource treatment.