The Influence Of Carbon Source On The Structure And Function Of The Bacterial Colony In The Acid Mine Wastewater Treatment Reactor

Acid Mine Drainage(AMD)is rich in heavy metals and sulfate ions,which is currently a serious global environmental problem.The treatment of AMD with microorganisms mainly composed of Sulfate-reducing bacteria(SRB)is one of the most promising treatment methods at present.Carbon source is an important factor that restricts the efficiency of microbial treatment of AMD.In-depth discussion of the removal mechanism of different carbon sources on AMD in the sulfuric acid reduction reactor has important reference significance for the actual engineering application of microbial treatment in AMD treatment.This thesis takes the continuous operation of the upflow anaerobic sludge blanket(UASB)for the treatment of AMD as the research object,and investigates the treatment of AMD with soluble starch,molasses,lactic acid,glucose,and glycerol as carbon sources.Investigate the removal of SO₄^2-reduction efficiency,TOC,Cu,Zn,Fe and other pollutants in the reactor.Using high-throughput sequencing of 16S r RNA genes to investigate the differences in microbial community diversity,structure,function,and microbial relationships in reactors under different carbon sources,and to clarify the internal relationship of“Carbon source-Microbial community-Treatment effect”,which can be The selection of carbon source in the sulfuric acid reduction bioreactor for the treatment of actual acid mine wastewater provides a theoretical basis.The main results of the paper are as follows:(1)When the influent SO₄^2-is 1050 mg/L,the COD/SO₄^2-is 0.67,and the p H is4.50,during the continuous and stable operation of the AMD treatment reactor,the reactors with glycerol,sodium lactate and molasses as carbon sources have higher sulfuric acid reduction efficiency.The average sulfate removal rates in the reactors of these three carbon sources are 63.25%,50.8%and48.55%respectively.But the reactor with glucose as the carbon source has the lowest sulfuric acid reduction efficiency,and its sulfuric acid reduction efficiency and effluent p H are 32.24%and 6.21 respectively.Under this sulfuric acid reduction effect,the five different carbon source reactors can remove metals well when treating AMD.Among them,the removal rate of copper and zinc is 100%,and the removal rate of iron is more than 96.55%.Elemental analysis further shows the removal of heavy metals.It precipitates in the bottom sludge in the form of metal sulfides.(2)In the stable operation period under the above operating conditions,the TOC of the reactor effluent varies with the addition of carbon sources.The reactor carbon source in descending order of TOC removal rate is:starch 90.9%,glucose 87.9%,molasses 87.1%,glycerol 86.9%,sodium lactate 83.4%.(3)Under the same operating conditions of reactors with different carbon sources,the structure and diversity of the bacterial community in the reactor have certain differences due to different carbon sources.In the reactor,the carbon sources that reduce the microbial species diversity(Shannon index)from high to low are sodium lactate,glycerin,molasses,glucose,and starch.This result is positively correlated with the sulfuric acid reduction efficiency of the reactor.The results of principal co-ordinates analysis(PCo A)showed that the microbial structures in the carbon source reactors for glycerol and sodium lactate were similar,while the microbial structures in the carbon sources of starch,molasses and glucose were closer.(4)After stable operation,the species and abundance of bacteria in different carbon source reactors also have obvious differences.For example,the abundance of Clostridiaceae?1 in the reactor is starch 18.87%,molasses 20.20%,sodium lactate8.44%,glucose 35.80%,glycerol 14.75%,and the abundance in the Prevotellaceae reactor is starch.33.34%,molasses 13.70%,sodium lactate 0.52%,glucose 6.95%,glycerol 0.59%.Correlation analysis shows that there is a significant correlation between some species differences and the sulfuric acid reduction efficiency in AMD,such as Burkholderiaceae,Acidithiobacillaceae,etc.,have a negative correlation with the removal of AMD,while Desulfobulbaceae,Desulfobacteriaceae,etc.The dominant SRB species such as Desulfobacteraceae are positively correlated with the removal of sulfate and metallic iron and the increase of p H.(5)The relationship between species is also an important factor affecting the structure of the bacterial colony.The network analysis of the bacterial community species in different carbon source reactors shows that the relationship between the bacterial community species in the reactor is based on the Proteobacteria and Firmicutes are key ecological network node species,and there are certain differences in different reactors.The relationship between community species in most reactors is positive,indicating that the relationship between different bacterial species in the reactor is mainly cooperative and mutually beneficial.There is a negative correlation between Prevotella in the starch reactor and Sphingopyxis in the molasses reactor,Clostridium?sensu?stricto?1 in the glucose reactor and other microorganisms,indicating that sulfate reducing bacteria and the most dominant bacteria There is a competitive relationship for the existence of nutritional factors such as carbon sources.(6)Different from the bacterial community structure,the functions of the microbial community in AMD treatment reactors with different carbon sources are similar,with only differences in functional abundance.Metabolism and Genetic Information Processing are the main components in Level 1 pathways,and all carbon source reactors are functionally consistent.There are significant differences in the abundance of Energy metabolism,replication and repair,and Glycan biosynthesis and metabolism in the Level 2 pathway.