以硝氮为主要氮源反硝化除磷细菌的驯化及影响因素研究

发布时间：2018-02-22 10:05

本文关键词： 生物除磷反硝化除磷细菌污泥驯化氮源　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：强化生物除磷技术(Enhance Biological Phosphorus Removal, EBPR)被普遍认为是一种经济有效的除磷方法,而反硝化除磷工艺作为EBPR中的新兴领域,已逐渐成为学者研究的焦点。该工艺是在厌氧/缺氧交替条件下,厌氧释磷之后,缺氧段利用硝酸盐或亚硝酸盐作为电子受体过量吸磷,最终通过排除富含磷的剩余污泥达到除磷的目的。因其与传统除磷方法相比具有诸多优势,人们陆续开始对反硝化除磷细菌的培养及相关影响因素进行研究。但报道的所有培养方式均是以氨氮作为氮源,并且因培养方式的差异,影响状况也存在分歧。本文首次探讨以硝氮为主要氮源的培养方式,驯化反硝化除磷细菌(Denitrifying phosphorus-accumulating organisms, DPAO),并针对亚硝氮和氨氮对其活性的影响进行相关研究。本文以活性污泥为种泥,通过序批式反应器(Sequencing batch reactor, SBR)在厌氧/缺氧/好氧交替的条件下驯化以硝酸盐作为主要氮源的反硝化除磷细菌。在330天的培养时间内,对不同驯化阶段的一个周期内氮磷等各指标变化进行研究及相应的动力学分析。通过荧光原位杂交和16S rRNA测序的分子生物学技术,确定菌体群落的组成。结果表明,随着驯化的进行,厌氧阶段释磷速度逐渐加快,释磷量增加,最终的去除率可达到91.8%,同时硝氮去除率可达100%。在此过程中,释磷和吸磷随时间变化的规律,符合一级动力学方程。通过分子生物学技术分析,聚磷菌占总菌的80.56%,其中反硝化除磷菌占50%以上,聚糖菌仅为5.6%。此外,在整个驯化过程中,水质和环境条件的变化使出水中磷浓度出现波动,而出水硝氮的变化不大。因此,以硝酸盐作为主要氮源培养DPAO的方式是可行的,拥有较好的脱氮除磷效率,并有利于使聚磷菌成为优势菌种。最后优化反应条件,达到长期稳定运行,同步脱氮和除磷的效果良好。同时,本文针对所培养的DPAO,考察了亚硝氮和氨氮对其活性的影响。批示实验结果表明缺氧段投加亚硝氮浓度在75 mg/L以下时,可作为电子受体进行除磷,浓度达到100 mg/L会开始产生抑制；进水中亚硝氮的存在会对DPAO释磷明显抑制。氨氮对DPAO的影响,表现在随着氨氮浓度的增加,厌氧释磷量和缺氧吸磷量有明显的增加。随后在序批式反应器中考察了亚硝氮和氨氮对DPAO的短期抑制及DPAO恢复能力。进水亚硝氮浓度为40 mg/L时；会先产生抑制随后可以恢复；浓度升至80 mg/L,抑制后难以完全恢复,去除率仅为原来的70%。而进水中含有80 mg/L氨氮时,释磷量和吸磷量均有所增加,但整体除磷效率并未有明显变化,氨氮消耗量恒定。
[Abstract]:Enhanced Biological Phosphorus removal (EBPRs) is widely considered as an economical and effective method for phosphorus removal. Denitrifying phosphorus removal process is a new field in EBPR. The process is that after anaerobic phosphorus release, nitrate or nitrite is used as electron acceptor to absorb phosphorus in anoxic stage. In the end, phosphorus removal can be achieved by removing excess sludge rich in phosphorus, because it has many advantages compared with traditional phosphorus removal methods. People began to study the culture of denitrifying phosphorus removal bacteria and related factors, but all the reported culture methods were ammonia nitrogen as a source of nitrogen, and because of the different culture methods, The effects of denitrification and denitrification phosphorus-accumulating organismsDPAON were investigated for the first time, and the effects of nitrite and ammonia nitrogen on their activity were also studied. In this paper, activated sludge was used as seed sludge. The denitrifying phosphorus removal bacteria with nitrate as the main nitrogen source were domesticated by sequencing batch reactor (SBR) under the condition of anaerobic / anoxic / aerobic alternation. The changes of nitrogen and phosphorus in one cycle at different acclimation stages were studied and the corresponding kinetic analysis was carried out. The composition of bacterial community was determined by fluorescence in situ hybridization and 16s rRNA sequencing. With the acclimation, the rate of phosphorus release in anaerobic stage was accelerated gradually, the amount of phosphorus release increased, the final removal rate of phosphorus reached 91.8%, and the removal rate of nitrate and nitrogen reached 100%. In this process, the regularity of phosphorus release and phosphorus absorption with time was observed. According to the first-order kinetic equation, through molecular biological analysis, it was found that phosphorus accumulating bacteria accounted for 80.56% of the total bacteria, of which denitrifying phosphorus removal bacteria accounted for more than 50%, and saccharomycetes only 5.6. In addition, during the whole domestication process, The change of water quality and environmental conditions caused the fluctuation of phosphorus concentration in effluent, but the change of nitrate and nitrogen in effluent was not obvious. Therefore, it is feasible to culture DPAO with nitrate as the main nitrogen source and has good efficiency of denitrification and phosphorus removal. Finally, the reaction conditions are optimized to achieve long-term stable operation, and the effect of simultaneous denitrification and phosphorus removal is good. In this paper, the effects of nitrite and ammonia on the activity of DPAO were investigated. The experimental results showed that when the concentration of nitrite was below 75 mg/L in anoxic stage, phosphorus could be removed as an electron receptor, and when the concentration reached 100 mg/L, it would be inhibited. The presence of nitrite in influent significantly inhibited the release of phosphorus from DPAO. The effect of ammonia nitrogen on DPAO was observed with the increase of ammonia nitrogen concentration. The short-term inhibition of nitrite and ammonia nitrogen on DPAO and the recovery ability of DPAO were investigated in a sequencing batch reactor. When the influent concentration of nitrite nitrogen was 40 mg/L, the inhibition could be first produced and then recovered. When the concentration rose to 80 mg / L, it was difficult to recover completely, and the removal rate was only 70%. When the influent contained 80 mg/L ammonia nitrogen, the phosphorus release and phosphorus uptake increased, but the overall phosphorus removal efficiency did not change obviously, and the ammonia nitrogen consumption was constant.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;X172

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