受銅抑制的活性污泥硝化菌群結(jié)構(gòu)演變及功能特征研究
發(fā)布時(shí)間：2018-12-24 14:27
【摘要】：活性污泥法是目前世界上普遍采用的廢水生物處理方法之一,然而由于活性污泥中微生物組成非常復(fù)雜,從分子生物學(xué)角度研究活性污泥系統(tǒng)凈水功能與微生物菌群結(jié)構(gòu)變化之間關(guān)系的報(bào)道還較少。本文研究了序批式反應(yīng)器(SBR)和缺氧/好氧(A/O)反應(yīng)器內(nèi)活性污泥系統(tǒng)中Cu的分布特點(diǎn)和Cu毒性沖擊對生物硝化功能的影響,利用Illumina測序和q-PCR等技術(shù)研究了全細(xì)菌和硝化菌菌群結(jié)構(gòu)以及硝化功能基因的動(dòng)態(tài)變化。定量分析了硝化功能基因的轉(zhuǎn)錄與硝化菌生理代謝的關(guān)系。研究了污泥旁路回流技術(shù)強(qiáng)化A/O工藝脫氮及改善污泥特性的效果和微生物特征。通過靜態(tài)試驗(yàn)研究發(fā)現(xiàn),細(xì)胞內(nèi)部的Cu對硝化菌呼吸速率的抑制符合飽和型生物毒性模型。SBR間歇式Cu濃度梯度投加試驗(yàn)發(fā)現(xiàn):氨氧化功能基因(amoA)和亞硝酸鹽氧化功能基因(nxrB)對Cu的毒性非常敏感,并且分別與氨氧化呼吸速率和亞硝酸鹽氮呼吸速率正相關(guān)。主成分回歸模型模擬結(jié)果顯示細(xì)胞內(nèi)部的Cu是抑制硝化菌活性的主要因素。Illumina測序結(jié)果顯示,當(dāng)Cu的生物量濃度達(dá)到13.0 mgCu/g·MLVSS時(shí),SBR中微生物的多樣性都被降低,菌群結(jié)構(gòu)發(fā)生較大變化。Zoogloea,Thauera和Dechloromonas是SBR中對Cu耐受性最高的屬,且均屬于β-proteobacteria綱下的Rhodocyclaceae目。門分類下的未知菌群(Unclassified)隨著Cu濃度的增加而急劇增加。本地建立的硝化菌16S rRNA數(shù)據(jù)庫有效提高了硝化菌的分辨率,并發(fā)現(xiàn)Nitrosomonas和Nitrospira分別是SBR中主要的氨氧化細(xì)菌(AOB)和亞硝酸鹽氧化細(xì)菌(NOB)。A/O反應(yīng)器的Cu連續(xù)投加試驗(yàn)結(jié)果表明amoA、反硝化功能基因nirS、napA和nosZ基因的轉(zhuǎn)錄水平在生物硝化受抑制及恢復(fù)過程中均是先增加后減小,而nxrB和反硝化功能基因nirK基因轉(zhuǎn)錄水平持續(xù)降低。各種微生物在Cu毒性條件下的變化規(guī)律與SBR試驗(yàn)不同。相比于沒有Cu投加的情況,當(dāng)總Cu濃度為16.50 mg/L時(shí),AOB的豐度明顯降低,而NOB的豐度卻明顯增加。受到Cu的強(qiáng)烈抑制之后,AOB種群的恢復(fù)能力要強(qiáng)于NOB。在污泥旁路回流工藝系統(tǒng)功能和微生物方面的研究中,發(fā)現(xiàn)該系統(tǒng)在低溫環(huán)境下能強(qiáng)化硝化菌的硝化作用,并且有效抑制污泥膨脹現(xiàn)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.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：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.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：X703;X172
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