【作者】 高珊珊；

【导师】 杨基先； 马放；

【作者基本信息】 哈尔滨工业大学 ， 微生物学， 2007， 硕士

【摘要】 近年来,国内外的不少研究和报道已能充分证明好氧反硝化菌的存在。这一发现突破了传统理论的认识,为生物脱氮技术提供了一种崭新的思路,并发展出在有氧条件下同步硝化反硝化的污水处理脱氮工艺。作为生物脱氮新技术之一的细菌好氧反硝化与传统的细菌厌氧反硝化相比更具有独特优势:1.好氧反硝化菌能在有氧条件下进行反硝化,使得同步硝化反硝化成为可能,硝化反应的产物可直接成为反硝化反应的底物,避免了培养过程亚硝酸盐和硝酸盐的积累对硝化反应的抑制,加速了硝化-反硝化进程。同时,反硝化作用补偿硝化反应消耗的碱度,维持了反应系统pH值稳定,降低了操作难度和运行成本。2.大部分好氧反硝化菌适应性较强、生长速度快、产量高并且溶解氧浓度要求较低,反硝化速度快且彻底,适合治理大面积氮污染水域。因此,进一步发掘好氧反硝化菌资源,并对其进行深入的研究已成为必然。本文通过定量投加硝酸盐和控制反应器曝气强度来驯化活性污泥以提高活性污泥在好氧条件下对硝酸盐的去除率,达到富集好氧反硝化菌的目的。筛选出五株快速去除硝酸盐的好氧反硝化细菌。根据16SrDNA序列分析确定了所筛菌的分类学和系统发育地位,并从其基因中扩增出与好氧反硝化作用相关的周质硝酸盐还原酶的亚基napA,为探讨其生理生化特性奠定基础。同时考察了五株菌在不同碳源以及C/N条件下的反硝化特性,当C/N为9时,筛选菌株均能进行完全的反硝化。当以丁二酸钠作为电子供体时,其脱氮效果最好。以G2和G5为例探讨了pH值和温度对反硝化效率的影响,当温度为25℃～35℃,pH值为中性偏碱,脱氮率能达到90%以上。本文采用活性污泥连续流反应器,探讨了好氧反硝化细菌对含硝氮废水的处理效果,并运用PCR-DGGE技术对运行期间反应器中微生物菌群结构的稳定性进行了分析。结果表明,在水温20℃～25℃,进水COD负荷402.14～288.57g/ (m~3·d),硝态氮负荷105.98～91.56g/(m~3·d),总氮负荷110.30～88.84g/ (m~3·d),pH值6.3～7.5,溶解氧(DO)≥5mg/L的条件下的稳定运行阶段,系统对于硝酸盐的平均去除率为98.35%,COD平均去除率为91.11%。变性梯度凝胶电泳(DGGE)结果显示,在系统稳定运行阶段,菌株G2和G5在反应器中能够稳定存在,并且逐渐成为优势菌群。更多还原

【Abstract】 In recent years, many domestic and foreign researches and reports have confirmed the existence of aerobic denitrifying bacteria. This discovery broke through the traditional theory, provided a brank-new idea for the biological nitrogen removal, and developed the nitrogen removal technology in sewage which is simultaneous nitrification and denitrification(SND). There are two predominance for aerobic denitrification, one of new technology for biological nitrogen removal, compared with traditional: first aerobic denitrifying bacteria can remove nitrogen under aerobic condition, which makes simultaneous nitrification and denitrification possible. The nitration product may directly become the denitrification substrate, which will suppress the accumulation of the nitrate and nitrous acid and accelerate the process of nitrification and denitrification.Simultaneously, the denitrification compensates the alkalinity consumed during nitrification, stabilizes pH value of reaction system, reduces the operation difficulty and the running cost. Second,aerobic denitrification has been adapted to disposing of large scale sewage due to the characteristic of aerobic denitrification bacteria: excelled adaptability, fast growth, high yield, relative low requirement for dissolved oxygen, fast denitrifing speed and complete reaction. Therefore it is necessary to exploit more aerobic denitrification bacteria and research them profoundly.In order to enrich the aerobic denitrification bacteria, The activated sludge was domesticated in sequencing batch reactor (SBR) reactor by adding rations nitrate and controlling the aeration intensity of reactor to enhance the removal of nitrate under aerobic condition. We screened five aerobic denitrifing bacteria, determined their phylogenetic status by phylogentic analysis based on partial 16SrDNA, and cloned their partial napA gene was cloned, the gene was subunit of periplasmic nitrate reduutase(NAR), which was considered to be relartive to aerobic denitrification.The carbon source test showed that as C/N ratio was 9, all strains can complete denitrification. When sodium succinate was used as electron donor, the denitrification effect was obviously more than that of carbon source and nitrogen removal rate were above 96%. We discussed the co-effect of pH radio and temperature to the denitrification efficiency of strains G2 and G5. When temperature was at 25℃～35℃and the optimal pH value was about 7, the nitrogen removal rate can reach up to 90%. Removal of wastewater containing nitrate nitrogen was performed using the activated sludge with aerobic denitrifying bacteria on continuous-flow reactor. The results showed that the average removal rate of nitrate nitrogen can be up to 98.35%, the average removal rate of COD can be up to 91.11% and the nitrite nitrogen in the effluent was kept in a lower level during the stable operating period, with pH radio was 6.3～7.5, influent COD loading of 402.14～288.57g/ (m~3·d) and nitrate nitrogen loading 105.98～91.56g/(m~3·d) at 20℃～25℃, and the dissolved oxygen concentration was kept at a high level(≥5mg/L). The results of DGGE showed that during the stable operating period, the aerobic denitrifying bacteria, G2 and G5, existed steadily, which were the dominant microorganisms all the time.更多还原