序批式颗粒污泥单级自养脱氮系统氮转化途径及菌群特性研究

发布时间：2018-06-20 20:24

本文选题：单级自养脱氮 + 颗粒污泥　；参考：《武汉理工大学》2015年硕士论文

【摘要】：随着氮素污染的加剧,废水生物脱氮技术已引起世界各国的普遍关注。单级自养脱氮工艺是指自养菌在单一系统内实现NH4+到N2的全部转化过程,整个过程不消耗有机碳源,耗氧量少,尤其适合处理高氨氮、低碳氮比废水,是一种极具应用前景的高效低耗生物脱氮技术。由于单级自养脱氮系统中氮转化途径复杂,可能涉及到全程硝化反硝化、短程硝化反硝化、厌氧氨氧化等多条脱氮途径,关于系统中的主导脱氮途径,目前研究尚存在争议;同时单级自养脱氮工艺在启动和运行过程中,脱氮途径可能会发生动态演替,这些都不利于该工艺的精确调控及性能优化,进而限制了其在实际工程中的应用。针对以上问题,本研究以颗粒污泥为介质,在SBR反应器内构建单级自养脱氮系统,结合批式实验和物料衡算,对系统启动中各阶段的脱氮途径进行动态研究,同时采用qPCR技术对系统不同阶段污泥的菌群结构进行定量分析。主要研究结论如下:(1)在SBR反应器中接种城市污水厂氧化沟系统硝化污泥,采用人工配置的高氨氮废水为进水,在温度为30±2℃,pH为8±0.2条件下,经好氧颗粒污泥培养、亚硝化启动和单级自养脱氮工艺启动三个阶段,反应器运行284天后成功实现了单级自养脱氮。在进水氨氮浓度为200mg·L-1时,系统氨氮转化率可达96.5%,脱氮率可达89.1%,脱氮性能良好。(2)采用物料衡算和批式实验相结合的手段,研究了系统启动中各阶段的氮转化途径。研究表明:①在好氧颗粒污泥阶段和亚硝化阶段,系统内主导脱氮途径是硝化反硝化脱氮途径。好氧颗粒污泥培养阶段,出水中氮所占比例为6%,反硝化去除的氮占72%,剩余污泥排走的氮为6%,系统的氮平衡为91.27%,。②亚硝化阶段,随着进水氨氮浓度逐渐升高和COD浓度逐渐降低,系统亚硝化效果越来越好,硝化反硝化途径所占的脱氮比例也逐渐降低,在第82d到第110d,通过反硝化作用去除的氮在70%以上,是系统最大的脱氮途径,到第114d后,反硝化脱氮比例显著下降,最终降至14.57%;同时通过出水带走的氮所占比例大幅上升,由最初的4.47%最终升至82.66%。③单级自养脱氮阶段,系统存在多种脱氮途径,分别为亚硝化+厌氧氨氧化、硝化反硝化和氨吹脱。各途径脱氮贡献率分别为:硝化反硝化7.32%,氨吹脱5%,亚硝化+厌氧氨氧化57.88%。同时,系统内存在两条厌氧氨氧化途径:途径一,一部分NH4+发生短程硝化生成NO2-,由NO2-生成NH2OH,NH2OH与剩余的NH4+反应生成N2H4,最终N2H4进一步转化为N2;途径二,由NH4+生成NH2OH,NH2OH再与系统内的NO2-反应生成N2O,最后转化为N2。途径一所占比例较大,为32.71%;途径二所占比例为25.16%。(3)采用实时荧光定量核酸扩增检测(qPCR)技术,以接种污泥、亚硝化污泥和单级自养脱氮污泥为对象,对其氨氧化菌(AOB)、亚硝酸盐氧化菌(NOB)、反硝化菌(DNF)和厌氧氨氧化菌(AAOB)等主要功能菌的动态演替进行了定量分析。结果表明:接种污泥、亚硝化污泥和单级自养脱氮污泥中的AAOB基因拷贝数分别645个·μL-1,6790个·μL-1和74800个·μL-1,说明AAOB在亚硝化阶段有小幅度的增加,在单级自养脱氮阶段大量的富集;三种污泥中AOB基因拷贝数分别为10600个·μL-1、28000个·μL-1和22000个·μL-1,说明AOB在亚硝化阶段得到大量的富集,在单级自养脱氮阶段AOB和AAOB形成有机的平衡,其数量稍微减少;接种污泥中NOB基因拷贝数量最多,为17610个·μL-1,在亚硝化阶段由于AOB的竞争,NOB被大量淘汰,其基因拷贝数减少至2830,在单级自养脱氮阶段,由于系统主要进行厌氧反应,NOB被进一步淘汰,基因拷贝数只有669个·μL-1,DNF基因拷贝数的变化规律同NOB。这一结果也验证了单级自养脱氮系统各启动阶段的主要氮转化途径研究是正确的。
[Abstract]:With the aggravation of nitrogen pollution, the biological denitrification technology of wastewater has caused widespread concern all over the world. Single autotrophic nitrogen removal technology refers to the complete transformation process of autotrophic bacteria to realize NH4+ to N2 in a single system. The whole process does not consume organic carbon source and has less oxygen consumption. It is especially suitable for high ammonia nitrogen and low carbon and nitrogen waste water. It is a kind of great application. The high efficiency and low consumption biological denitrification technology in the future. Due to the complexity of nitrogen conversion in the single stage autotrophic and denitrification system, it may involve many ways of denitrification, short range nitrification and denitrification, anaerobic ammonia oxidation and other ways of denitrification. There are still disputes about the leading denitrification pathway in the system. In the process of operation, the dynamic succession of nitrogen removal pathway may occur, which are not conducive to the precise control and performance optimization of the process, and thus restrict its application in practical engineering. In view of the above problems, this study uses granular sludge as the medium to construct a single stage autotrophic nitrogen removal system in the SBR reactor, combined with batch experiment and material balance calculation. The dynamic study of the denitrification pathway at various stages of the system was carried out, and the qPCR technique was used to quantitatively analyze the structure of the sludge in different stages of the system. The main conclusions are as follows: (1) inoculating the nitrification sludge in the oxidation ditch system of the urban sewage plant in the SBR reactor, and using the high ammonia nitrogen wastewater as the influent in the human configuration, at a temperature of 30 + 2 Under the condition of 8 + 0.2 pH, the aerobic granular sludge culture, nitrification start and single stage autotrophic nitrogen removal process started three stages, and the single stage autotrophic nitrogen removal was achieved successfully after the reactor operation 284 days. When the influent ammonia nitrogen concentration is 200mg L-1, the system ammonia nitrogen conversion rate can reach 96.5%, the nitrogen removal rate is up to 89.1%, and the denitrification performance is good. (2) materials are adopted. The nitrogen conversion pathway at various stages of the system was studied by means of balance calculation and batch experiment. The study showed that: (1) the dominant denitrification pathway in the aerobic granular sludge stage and nitrification stage is nitrification denitrification denitrification. The proportion of nitrogen in the effluent of aerobic granular sludge is 6%, and the denitrification nitrogen is 72. The nitrogen balance of the residual sludge was 6% and the nitrogen balance of the system was 91.27%. (2) the nitrification stage, with the gradual increase of the ammonia nitrogen concentration and the gradual decrease of the COD concentration, the system nitrification effect became better and better. The denitrification ratio of nitrification and denitrification was gradually reduced, and the nitrogen removal by denitrification was more than 70% in 82d to 110D. It is the largest denitrification pathway of the system. After 114d, the denitrification denitrification ratio decreases significantly and eventually drops to 14.57%, while the proportion of nitrogen taken away by the effluent rises substantially, from the initial 4.47% to the single stage autotrophic nitrogen removal stage, and there are a variety of denitrification pathways, respectively, nitrification + ANAMMOX, nitrification and denitrification. The contribution rates of nitrogen removal are as follows: nitrification and denitrification 7.32%, ammonia stripping 5%, nitrification and anammox 57.88%. simultaneously, the system is stored in two anammox pathways: one, one part of NH4+ produces NO2-, NH2OH is generated by NO2-, NH2OH and the remaining NH4+ react to N2H4, and N2H4 is eventually transformed into N2; route two, NH2OH is generated by NH4+, and NH2OH is reacted with NO2- in the system to generate N2O. Finally, the proportion of N2. pathway is larger, 32.71%, and the proportion of the two is 25.16%. (3) using real time fluorescence quantitative nucleic acid amplification detection (qPCR) technology to inoculate the sludge, nitrosation sludge and single autotrophic denitrification sludge as the object and ammonia. The dynamic succession of major functional bacteria, such as oxidizing bacteria (AOB), nitrite oxidizing bacteria (NOB), denitrifying bacteria (DNF) and anaerobic ammonia oxidizing bacteria (AAOB), was quantitatively analyzed. The results showed that the copies of AAOB gene copies in the inoculated sludge, nitrosation sludge and single autotrophic nitrogen removal sludge were 645. Mu, L-16790, mu L-1 and 74800. Mu L-1, respectively, indicating AAOB There is a small increase in the nitrosation stage and a large amount of enrichment in the stage of single autotrophic nitrogen removal. The number of copies of AOB genes in the three kinds of sludge are 10600. L-128000, mu L-1 and 22000. L-1 respectively, indicating that AOB has been enriched in the nitrosation stage and formed an organic balance in the single stage autotrophic denitrification stage AOB and AAOB, with a slight amount of it. The number of NOB gene copies in the inoculated sludge was the most, 17610. Mu L-1. In the nitrosation stage, the NOB was eliminated by the competition of AOB, and the copy number of the gene was reduced to 2830. In the single stage autotrophic nitrogen removal stage, the NOB was only 669. L-1, and the copy number of the DNF gene was only 669. L-1. The results show that the main nitrogen transformation pathway in the start-up stage of the single stage autotrophic nitrogen removal system is correct by NOB..
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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