受铜抑制的活性污泥硝化菌群结构演变及功能特征研究
发布时间：2018-12-24 14:27
【摘要】：活性污泥法是目前世界上普遍采用的废水生物处理方法之一,然而由于活性污泥中微生物组成非常复杂,从分子生物学角度研究活性污泥系统净水功能与微生物菌群结构变化之间关系的报道还较少。本文研究了序批式反应器(SBR)和缺氧/好氧(A/O)反应器内活性污泥系统中Cu的分布特点和Cu毒性冲击对生物硝化功能的影响,利用Illumina测序和q-PCR等技术研究了全细菌和硝化菌菌群结构以及硝化功能基因的动态变化。定量分析了硝化功能基因的转录与硝化菌生理代谢的关系。研究了污泥旁路回流技术强化A/O工艺脱氮及改善污泥特性的效果和微生物特征。通过静态试验研究发现,细胞内部的Cu对硝化菌呼吸速率的抑制符合饱和型生物毒性模型。SBR间歇式Cu浓度梯度投加试验发现:氨氧化功能基因(amoA)和亚硝酸盐氧化功能基因(nxrB)对Cu的毒性非常敏感,并且分别与氨氧化呼吸速率和亚硝酸盐氮呼吸速率正相关。主成分回归模型模拟结果显示细胞内部的Cu是抑制硝化菌活性的主要因素。Illumina测序结果显示,当Cu的生物量浓度达到13.0 mgCu/g·MLVSS时,SBR中微生物的多样性都被降低,菌群结构发生较大变化。Zoogloea,Thauera和Dechloromonas是SBR中对Cu耐受性最高的属,且均属于β-proteobacteria纲下的Rhodocyclaceae目。门分类下的未知菌群(Unclassified)随着Cu浓度的增加而急剧增加。本地建立的硝化菌16S rRNA数据库有效提高了硝化菌的分辨率,并发现Nitrosomonas和Nitrospira分别是SBR中主要的氨氧化细菌(AOB)和亚硝酸盐氧化细菌(NOB)。A/O反应器的Cu连续投加试验结果表明amoA、反硝化功能基因nirS、napA和nosZ基因的转录水平在生物硝化受抑制及恢复过程中均是先增加后减小,而nxrB和反硝化功能基因nirK基因转录水平持续降低。各种微生物在Cu毒性条件下的变化规律与SBR试验不同。相比于没有Cu投加的情况,当总Cu浓度为16.50 mg/L时,AOB的丰度明显降低,而NOB的丰度却明显增加。受到Cu的强烈抑制之后,AOB种群的恢复能力要强于NOB。在污泥旁路回流工艺系统功能和微生物方面的研究中,发现该系统在低温环境下能强化硝化菌的硝化作用,并且有效抑制污泥膨胀现象。
[Abstract]:Activated sludge process is one of the widely used wastewater treatment methods in the world. However, the microbial composition of activated sludge is very complex. There are few reports on the relationship between the water purification function of activated sludge system and the change of microbial flora structure from the point of view of molecular biology. The distribution characteristics of Cu in (SBR) and anoxic / aerobic (A / O) reactor and the effect of Cu toxicity shock on the biological nitrification function were studied in this paper. Illumina sequencing and q-PCR techniques were used to study the dynamic changes of bacterial and nitrifying bacteria community structure and nitrification function genes. The relationship between nitrifying function gene transcription and physiological metabolism of nitrifying bacteria was analyzed quantitatively. The effect of sludge bypass reflux technology on denitrification and improvement of sludge characteristics in A- O process was studied. The static test results show that, The inhibition of respiratory rate of nitrifying bacteria by Cu in cells was in accordance with the saturated biotoxicity model. The results of SBR intermittent Cu concentration gradient test showed that the ammonia oxidation function gene (amoA) and nitrite oxidation function gene (nxrB) were used in the experiment. The toxicity of Cu is very sensitive, And it was positively correlated with ammonia oxidation respiration rate and nitrite nitrogen respiration rate, respectively. The results of principal component regression model showed that Cu was the main factor to inhibit the activity of nitrifying bacteria. Illumina sequencing showed that when the concentration of Cu reached 13.0 mgCu/g MLVSS, the diversity of microbes in SBR was decreased. Zoogloea,Thauera and Dechloromonas were the most tolerant genera to Cu in SBR, and they belonged to Rhodocyclaceae order of 尾-proteobacteria class. The (Unclassified) of unknown flora increased sharply with the increase of Cu concentration. The 16s rRNA database of nitrifying bacteria established locally improves the resolution of nitrifying bacteria effectively. It was found that Nitrosomonas and Nitrospira were the main ammonia-oxidizing bacteria (AOB) in SBR and (NOB). A / O reactor for nitrite oxidation respectively. The results of Cu continuous addition test showed that amoA, denitrification function gene nirS,. The transcription level of napA and nosZ genes increased at first and then decreased during the inhibition and restoration of bionitrification, while the transcription level of nxrB and nirK gene of denitrification function gene decreased continuously. The variation of various microorganisms under Cu toxicity is different from that of SBR test. When the total Cu concentration was 16.50 mg/L, the abundance of AOB decreased significantly, but the abundance of NOB increased significantly. After being strongly inhibited by Cu, the recovery ability of AOB population is stronger than that of NOB.. In the study of sludge by-pass reflux system function and microorganism, it was found that the system could enhance nitrification of nitrifying bacteria in low temperature environment, and effectively inhibit sludge bulking phenomenon.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：X703;X172
[Abstract]:Activated sludge process is one of the widely used wastewater treatment methods in the world. However, the microbial composition of activated sludge is very complex. There are few reports on the relationship between the water purification function of activated sludge system and the change of microbial flora structure from the point of view of molecular biology. The distribution characteristics of Cu in (SBR) and anoxic / aerobic (A / O) reactor and the effect of Cu toxicity shock on the biological nitrification function were studied in this paper. Illumina sequencing and q-PCR techniques were used to study the dynamic changes of bacterial and nitrifying bacteria community structure and nitrification function genes. The relationship between nitrifying function gene transcription and physiological metabolism of nitrifying bacteria was analyzed quantitatively. The effect of sludge bypass reflux technology on denitrification and improvement of sludge characteristics in A- O process was studied. The static test results show that, The inhibition of respiratory rate of nitrifying bacteria by Cu in cells was in accordance with the saturated biotoxicity model. The results of SBR intermittent Cu concentration gradient test showed that the ammonia oxidation function gene (amoA) and nitrite oxidation function gene (nxrB) were used in the experiment. The toxicity of Cu is very sensitive, And it was positively correlated with ammonia oxidation respiration rate and nitrite nitrogen respiration rate, respectively. The results of principal component regression model showed that Cu was the main factor to inhibit the activity of nitrifying bacteria. Illumina sequencing showed that when the concentration of Cu reached 13.0 mgCu/g MLVSS, the diversity of microbes in SBR was decreased. Zoogloea,Thauera and Dechloromonas were the most tolerant genera to Cu in SBR, and they belonged to Rhodocyclaceae order of 尾-proteobacteria class. The (Unclassified) of unknown flora increased sharply with the increase of Cu concentration. The 16s rRNA database of nitrifying bacteria established locally improves the resolution of nitrifying bacteria effectively. It was found that Nitrosomonas and Nitrospira were the main ammonia-oxidizing bacteria (AOB) in SBR and (NOB). A / O reactor for nitrite oxidation respectively. The results of Cu continuous addition test showed that amoA, denitrification function gene nirS,. The transcription level of napA and nosZ genes increased at first and then decreased during the inhibition and restoration of bionitrification, while the transcription level of nxrB and nirK gene of denitrification function gene decreased continuously. The variation of various microorganisms under Cu toxicity is different from that of SBR test. When the total Cu concentration was 16.50 mg/L, the abundance of AOB decreased significantly, but the abundance of NOB increased significantly. After being strongly inhibited by Cu, the recovery ability of AOB population is stronger than that of NOB.. In the study of sludge by-pass reflux system function and microorganism, it was found that the system could enhance nitrification of nitrifying bacteria in low temperature environment, and effectively inhibit sludge bulking phenomenon.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：X703;X172
【相似文献】
相关期刊论文 前10条
1 王歆鹏,陈坚,华兆哲,伦世仪,乐涛;硝化菌群在不同条件下的增殖速率和硝化活性[J];应用与环境生物学报;1999年01期
2 崔文娟;董琳茜;孙s钍，
本文编号：2390744
本文链接：https://www.wllwen.com/shoufeilunwen/jckxbs/2390744.html
