好氧污泥强化造粒过程中不同元素的空间分布规律及微生物群落演替特征

发布时间：2018-06-25 06:54

本文选题：好氧污泥 + 强化造粒　；参考：《西安建筑科技大学》2017年硕士论文

【摘要】：好氧颗粒污泥以其良好的沉降性能、密实的结构、较高的生物量和对有害物质的吸附能力受到了国内外研究者的广泛关注。但是,启动时间长和运行稳定性差是好氧颗粒污泥技术目前面临的主要问题。本研究通过在好氧污泥颗粒化初期(10~16天)投加硫酸铝的方式来加速好氧污泥的颗粒化进程,并进一步通过在解体的好氧颗粒污泥中短期投加硫酸铝(91~93天)来加速解体好氧颗粒污泥的再形成。采用X荧光光谱仪测定元素含量,扫描电镜和能量弥散X射线光谱仪联用的方法测定元素的空间分布,并使用变性梯度凝胶电泳(DGGE)技术对期间微生物的群落演替特征进行了分析。研究结果如下:(1)在SBR反应器运行的10~16天投加硫酸铝强化造粒可以加速好氧污泥的颗粒化进程,并且强化造粒形成的颗粒污泥机械强度高、生物量高、沉降性好、平均粒径大。同时,硫酸铝的投加并未对COD、TN和NH4+的去除率造成明显影响,但在一定程度上可以提高TP的去除率。(2)在强化造粒形成的颗粒污泥中,其Al元素含量从16天的45.69±0.55%逐渐下降至43天的1.09±0.39%,总体呈一个近似线性下降的趋势,而自然形成的颗粒中Al元素含量始终低于0.02%。与此同时,颗粒中P和S元素的含量分别由7.21±0.047%和32.11±0.23%逐渐回升至13.64±0.071%和47.82±0.21%。在成熟后的颗粒中,Al元素和P元素主要以沉淀物的形式分布在污泥颗粒的核心。这说明混凝剂投加期间微生物之间的聚集方式以物化絮凝为主,混凝剂投加停止后微生物的自絮凝逐渐替代了混凝剂的无机絮凝,成为微生物聚集的主要手段。这样的结果证明了Al3+强化造粒过程是一个物化-生化的耦合过程。(3)通过DGGE技术分析了强化造粒期间污泥内微生物的群落演替特征。对DGGE图谱和相应的测序结果分析后发现,强化造粒形成的颗粒污泥和自然形成的颗粒污泥之间微生物群落结构并无明显差异,这说明硫酸铝的投加未对颗粒污泥内微生物的种群结构造成明显影响。其中,颗粒污泥内的优势菌群主要分布于变形菌门(Proteobacteria),假单胞菌(Pseudomonas)是其中的主要菌属。(4)在成熟的好氧颗粒污泥解体后,向其中短期投加硫酸铝可以有效加速颗粒污泥的再形成,并且通过强化方式再形成的颗粒污泥比自然修复形成的颗粒污泥具有更加良好的污泥特性和更高的细菌总数。同时,硫酸铝的投加在一定程度上改变了污泥中微生物的EPS组分。对DGGE图谱和相应的测序结果分析后发现,加药结束后的第7天,通过强化方式再形成的颗粒污泥中微生物多样性更加丰富。而20天后,两个反应器中微生物的多样性已无明显差异。这说明好氧颗粒污泥的解体会导致其内部微生物的多样性出现下降,而硫酸铝的投加促进了其中微生物的相互聚集,从而有效加速了好氧颗粒污泥内微生物多样性的恢复。
[Abstract]:Aerobic granular sludge has been widely concerned by researchers at home and abroad for its good settling performance, dense structure, high biomass and adsorption ability to harmful substances. However, long start-up time and poor operational stability are the main problems of aerobic granular sludge technology. In this study, the process of aerobic sludge granulation was accelerated by adding aluminum sulfate in the initial stage of aerobic sludge granulation (10 ~ 16 days). Furthermore, the dissolution of aerobic granular sludge was accelerated by adding aluminum sulfate (91 ~ 93 days) to the decomposed aerobic granular sludge for a short period of time. The content of elements was determined by X-ray fluorescence spectrometer, and the spatial distribution of elements was determined by means of scanning electron microscope and energy dispersive X-ray spectrometer. Denaturing gradient gel electrophoresis (DGGE) was used to analyze the community succession characteristics of microbes during the period. The results are as follows: (1) the granulation process of aerobic sludge can be accelerated by adding aluminum sulfate in SBR reactor for 10 ~ 16 days, and the granulated sludge formed by enhanced granulation has high mechanical strength, high biomass, good sedimentation and large average particle size. At the same time, the addition of aluminum sulfate has no obvious effect on the removal rate of COD, TN and NH _ 4, but to some extent can improve the removal rate of TP. (2) in granulated sludge formed by enhanced granulation, The Al content decreased gradually from 45.69 卤0.55% in 16 days to 1.09 卤0.39 in 43 days, and the content of Al in the naturally formed particles was always lower than 0.02%. At the same time, the contents of P and S gradually increased from 7.21 卤0.047% and 32.11 卤0.23% to 13.64 卤0.071% and 47.82 卤0.21%, respectively. In the mature particles, Al and P elements mainly distribute in the core of sludge granules as precipitates. This shows that the main way of microbial aggregation during coagulant is physico-chemical flocculation, and the self-flocculation of microorganisms gradually replaces the inorganic flocculation of coagulant and becomes the main means of microbial aggregation after the coagulant is stopped. The results show that the process of enhanced Al3 granulation is a physico-chemical-biochemical coupling process. (3) the characteristics of microbial community succession in sludge during enhanced granulation were analyzed by DGGE. The analysis of DGGE map and sequencing results showed that there was no significant difference in microbial community structure between granular sludge formed by enhanced granulation and granular sludge formed naturally. This indicated that the addition of aluminum sulfate had no obvious effect on the microbial population structure in granular sludge. Among them, the dominant microflora in granular sludge is mainly distributed in Proteobacteria, Pseudomonas is one of the main bacteria. (4) after the dissolution of mature aerobic granular sludge, the short-term addition of aluminum sulfate to the granular sludge can effectively accelerate the formation of granular sludge. And the granular sludge formed by reinforcement has better characteristics of sludge and higher bacterial count than that formed by natural remediation. At the same time, the addition of aluminum sulfate changed the EPS component of microorganisms in sludge to some extent. The analysis of DGGE map and corresponding sequencing results showed that the microbial diversity in granular sludge which was formed by the way of reinforcement was more abundant on the 7th day after the drug was added. After 20 days, there was no significant difference in microbial diversity between the two reactors. This indicated that the dissolution of aerobic granular sludge would lead to the decrease of microbial diversity in aerobic granular sludge, and the addition of aluminum sulfate promoted the mutual aggregation of microbes in aerobic granular sludge, thus effectively accelerating the recovery of microbial diversity in aerobic granular sludge.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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