【作者】 刘伟；

【导师】 金鹏康；

【作者基本信息】 西安建筑科技大学 ， 环境科学与工程， 2023， 硕士

【摘要】 城市污水管道中污水流速是影响产甲烷菌（Methanogenic Archaea,MA）和硫酸盐还原菌（Sulfate-Reducing Bacteria,SRB）分布及代谢的关键因素。论文系统地研究了污水管道中流速变化对甲烷和硫化物生成的影响特性,探究了不同污水流速下MA和SRB的菌群分布变化规律及其代谢功能转变特性,解析了MA和SRB的之间的代谢关联关系及其水力扰动机理,研究结果为实现城市污水管道中甲烷和硫化物的水力调控提供理论基础。运用微生物测序方法与分箱分析手段,探究了污水管道中MA和SRB的代谢关联关系,结果表明,部分分箱中存在多种甲烷代谢和硫化物代谢关键基因,这些分箱均独自具有同步生成甲烷和硫化物的潜在功能;而其它分箱中仅存有单种甲烷代谢或硫化物代谢关键基因,此类分箱需协同代谢以完成甲烷和硫化物的生成过程,由此构成了MA和SRB之间的两种代谢关联关系。通过探究不同流速下MA和SRB的菌群分布变化规律,结果发现,管道中主导甲烷释放的菌属为Methanothrix、Methanobacterium,主导硫化物释放菌属为Desulfomonile、Desulfobulbus、Desulfovibrio等。随着流速升高,MA菌群相对丰度升高,SRB菌群相对丰度降低,说明流速会改变MA和SRB菌群分布,进而影响二者之间的代谢关联关系。将测序结果与KEGG数据库对比,获得的MA和SRB各代谢层级功能基因注释结果表明,流速从0.1 m·s^-1升高至0.7 m·s^-1时,污水管道中微生物的碳代谢、氮代谢和能量代谢功能基因相对丰度分别升高0.12%、0.08%和0.13%,其对应功能将逐渐增强;在能量代谢组中,甲烷代谢功能基因相对丰度升高0.21%,而硫化物代谢功能基因相对丰度降低0.12%,可见污水流速升高会削弱SRB的硫化物代谢能力,从而影响MA和SRB之间的共生关联关系,在一定程度上抑制了污染物的产生。通过检测分析不同流速下甲烷代谢、硫化物代谢通路中的关键酶、基因相对丰度变化和控制流速调控菌群代谢及气体产生过程,研究了污水管道中MA和SRB的水力调控机制,结果表明,当流速从0.1 m·s^-1升高至0.7 m·s^-1时,甲烷代谢通路中关键酶、基因相对丰度会升高,污水管道中甲烷浓度升高1倍左右,而硫化物代谢通路中关键酶、基因相对丰度则会降低,同时硫化物浓度也会迅速降低达到72%。因此,通过控制流速来影响甲烷代谢和硫化物代谢过程,减少甲烷代谢和硫化物代谢之间的物质交换,弱化二者的代谢关联关系,实现调控管道中甲烷和硫化物释放的目的。更多还原

【Abstract】 The sewage flow rate in urban sewage pipelines is a crucial factor affecting the distribution and metabolism of Methanogenic Archaea（MA）and Sulfate-Reducing Bacteria（SRB）.This work systematically studied the response characteristics of flow velocity in sewage pipes on methane and sulfide generation,explored the change rule of bacterial distribution and metabolic function transformation characteristics of MA and SRB under different sewage flow velocities,and analyzed the metabolic correlation between MA and SRB and their hydraulic disturbance mechanism.This work provides a theoretical basis for hydraulic control of methane and sulfide in municipal sewage pipes.The metabolic correlation between MA and SRB in sewage pipes was investigated by microbial sequencing and bin analysis methods.The results showed several critical genes in methane metabolism and sulfide metabolism in some of the bins.These bins had the potential function of synchronously producing methane and sulfide.However,other compartments contain only a critical gene for methane or sulfide metabolism.Such compartments require collaborative metabolism to complete the formation process of methane and sulfide,thus constituting two metabolic associations between MA and SRB.By exploring the distribution of MA and SRB bacteria at different flow rates,it was found that Methanothrix and Methanobacterium dominated the methane release in the pipeline.Desulfomonile,Desulfobulbus,Desulfovibrio are the dominant sulfide-releasing bacteria.The relative abundance of MA bacteria is going up,and the relative abundance of SRB bacteria is going down with the increase in flow rate,indicating that the flow rate is changing the distribution of MA and SRB bacteria,thereby affecting their metabolic correlation.The sequencing results were compared with the KEGG database.The functional gene annotation results of MA and SRB metabolic levels showed that the relative abundance of functional genes of carbon metabolism,nitrogen metabolism,and energy metabolism increased by 0.12%,0.08%,and 0.13%,respectively,when the flow velocity increased from 0.1 m·s^-1 to 0.7 m·s^-1.Its corresponding function will be gradually enhanced In the energy metabolism group,the relative abundance of methane metabolism functional genes increased by 0.21%,while the relative abundance of sulfide metabolism functional genes decreased by 0.12%.It can be seen that the increase in sewage flow rate will weaken the sulfide metabolism capacity of SRB,thus affecting the symbiotic association between MA and SRB and inhibiting the production of pollutants to some extent.The hydraulic regulation mechanism of MA and SRB in sewage pipes was studied by detecting and analyzing the relative abundance changes of critical enzymes and genes in methane metabolism and sulfide metabolism pathway and the process of regulating bacterial metabolism and gas production under the control of flow velocity.The results showed that when the flow velocity increased from 0.1 m·s^-1 to 0.7 m·s^-1,the relative abundance of key enzymes and genes in the methane metabolic pathway increased.As a result,the methane concentration in the sewage pipe will increase about once,while the relative abundance of key enzymes and genes in the sulfide metabolic pathway will decrease.The sulfide concentration will also decrease rapidly to 72%.Therefore,the process of methane metabolism and sulfide metabolism is affected by controlling the flow velocity to reduce the material exchange between methane metabolism and sulfide metabolism,weaken the metabolic correlation between the two,and achieve the purpose of regulating the release of methane and sulfide in the pipeline.更多还原