Anammox系统对温度变化的响应规律研究
发布时间：2018-09-11 15:49
【摘要】：厌氧氨氧化技术作为一种高效的生物脱氮方法,获得了大量的研究和一定程度的实践应用,但该系统的运行温度大多控制在中温范围内(35℃)。而实际废水温度往往处于常温甚至低温状态。为此,研究厌氧氨氧化对低温的响应机制,进而建立高效、稳定的低温厌氧氨氧化系统,对拓宽该技术的应用范围就有重要的意义。基于此,本文利用实验室规模的UASB厌氧氨氧化系统,采用梯度降温方式,研究了温度变化对厌氧氨氧化活性影响的规律,考察了整个降温过程中系统的脱氮性能、污泥理化性质和微生物种群结构等变化特征。获得的主要研究结论如下:(1)长周期试验研究表明,随着温度降低,系统的脱氮能力逐渐下降,平均总氮去除负荷从33℃的7.587 kgN m-3 d-3降至13℃和8℃的4.47和3.192 kgN m-3 d-3。各降温初期的出水水质波动明显,且温度越低,氨氮、亚硝态氮的最大出水浓度越高,系统重新恢复稳定所需要的时间也越长。整个降温过程中,进水游离亚硝酸FNA,是系统是否发生紊乱的关键因素,其限值约为60μg/L,当反应器内浓度高于该值时,系统的脱氮效率也随之下降。(2)分析了降温过程中污泥原位活性和非原位活性的变化趋势,结果表明,污泥原位活性随着反应器温度降低而降低,33和13℃反应器内污泥活性分别为0.102和0.023 gN g-1VSS d-1,这是系统脱氮能力下降的主要原因。不同温度阶段的污泥,其非原位活性均随温度的降低而降低,可见降温过程中污泥的最适生长温度并未发生转变,仍在33℃左右。长期处于低温环境下的污泥(18、13℃),其在低温范围内的活性相比稳定运行于33℃下的污泥,有了显著的提高,这归功于污泥在低温环境下长期的驯化。根据阿伦尼乌斯方程,本实验中的厌氧氨氧化反应活化能Ea在23-13和33-23℃下分别为89.6和16.4 kJ/mol。温度越低,温度对反应的影响越大。(3)温度下降不仅改变了污泥的外观颜色、形状,还影响了系统中胞外聚合物EPS的含量,23℃下EPS总量明显降低,但反应器温度降至18、13℃后,该值又重新增加,其中相比多糖,蛋白质含量波动更大。另外,污泥平均粒径在温度从33℃降至28℃后明显增加(2.693增至3.389 mm),其后随着温度的下降而逐渐减小,13℃下减至2.275 mm,相应的粒径最集中的范围从33℃时的2.5-3mm变成13℃的1.5-2 mm。污泥沉降速度的变化与VSS/SS值呈负相关。(4)温度下降,微生物群落的多样性呈下降趋势,13℃时变化显著。温度从33℃降至23℃后,浮霉菌门的相对丰度从9.04%逐渐升至16.02%,温度进一步降低至13℃,该值出现了显著的下降,但是长期13℃驯化后又重新升高至56.34%。微生物属水平结果显示,本实验接种污泥仅含Candidatus Kuenenia这一种厌氧氨氧化菌,在实验末期(第199天),其在浮霉菌门下的丰度在高达98%,在总菌种中的丰度为55.18%。整个降温过程中未发现其他厌氧氨氧化菌种,反应器内优势厌氧氨氧化菌种并不会随温度变化而改变。另外,qPCR结果显示,AMX基因拷贝数随温度下降呈先减后增的趋势,相反,单位细胞厌氧氨氧化活性值则先增后增,23℃是温度关键点。
[Abstract]:Anaerobic ammonia oxidation technology, as an efficient biological denitrification method, has obtained a lot of research and practical application to a certain extent, but the operating temperature of the system is mostly controlled in the range of medium temperature (35 C). However, the actual wastewater temperature is often in the state of normal temperature or even low temperature. Establishing a high efficient and stable low temperature anaerobic ammonia oxidation system is of great significance for widening the application range of this technology. Based on this, the effect of temperature variation on the activity of anaerobic ammonia oxidation was studied by using a laboratory scale UASB anaerobic ammonia oxidation system and a gradient cooling method. The main conclusions are as follows: (1) With the decrease of temperature, the denitrification capacity of the system gradually decreases, and the average total nitrogen removal load decreases from 7.587 kgN M-3 D-3 to 4.47 kgN M-3 D-3 and 3.192 kgN M-3 D-3 at 33 C and 8 C respectively. The lower the temperature, the higher the maximum effluent concentration of ammonia nitrogen and nitrite nitrogen, and the longer the time needed for the system to restore stability. The results showed that the in-situ and Non-in-situ activities of sludge decreased with the decrease of reactor temperature, and the sludge activities in 33 and 13 C reactors were 0.102 and 0.023 gN g-1VSS d-1, respectively, which were the main reasons for the decrease of nitrogen removal capacity of the system. In the same temperature stage, the Non-in-situ activity of sludge decreases with the decrease of temperature. It can be seen that the optimum growth temperature of sludge does not change during the cooling process, but is still around 33 C. According to Arrhenius equation, the activation energy Ea of anaerobic ammonia oxidation reaction in this experiment was 89.6 kJ/mol at 23-13 and 16.4 kJ/mol at 33-23. The lower the temperature, the greater the effect of temperature on the reaction. (3) The decrease of temperature not only changed the appearance and shape of the sludge, but also affected the system. The content of EPS in the medium-sized extracellular polymer decreases obviously at 23 C, but it increases again when the reactor temperature drops to 18 C and 13 C. Compared with the polysaccharide, the protein content fluctuates more greatly. (4) Temperature decreased, microbial community diversity showed a downward trend and a significant change at 13 ~C. The relative abundance of Phytophthora decreased from 9.04% to 9.04% after the temperature dropped from 33 ~C to 23 ~C. The microbial level showed that the sludge inoculated in this experiment contained only Candidatus Kuenenia, an anaerobic ammonia-oxidizing bacterium, and its abundance under Phytophthora was as high as that at the end of the experiment (day 199). No other anaerobic ammonia-oxidizing bacteria were found during the whole cooling process, and the dominant anaerobic ammonia-oxidizing bacteria in the reactor did not change with temperature. In addition, qPCR results showed that the copy number of AMX gene decreased first and then increased with the decrease of temperature. On the contrary, the activity value of anaerobic ammonia-oxidizing bacteria per unit cell decreased. First increase and then increase, 23 C is the key point of temperature.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703
[Abstract]:Anaerobic ammonia oxidation technology, as an efficient biological denitrification method, has obtained a lot of research and practical application to a certain extent, but the operating temperature of the system is mostly controlled in the range of medium temperature (35 C). However, the actual wastewater temperature is often in the state of normal temperature or even low temperature. Establishing a high efficient and stable low temperature anaerobic ammonia oxidation system is of great significance for widening the application range of this technology. Based on this, the effect of temperature variation on the activity of anaerobic ammonia oxidation was studied by using a laboratory scale UASB anaerobic ammonia oxidation system and a gradient cooling method. The main conclusions are as follows: (1) With the decrease of temperature, the denitrification capacity of the system gradually decreases, and the average total nitrogen removal load decreases from 7.587 kgN M-3 D-3 to 4.47 kgN M-3 D-3 and 3.192 kgN M-3 D-3 at 33 C and 8 C respectively. The lower the temperature, the higher the maximum effluent concentration of ammonia nitrogen and nitrite nitrogen, and the longer the time needed for the system to restore stability. The results showed that the in-situ and Non-in-situ activities of sludge decreased with the decrease of reactor temperature, and the sludge activities in 33 and 13 C reactors were 0.102 and 0.023 gN g-1VSS d-1, respectively, which were the main reasons for the decrease of nitrogen removal capacity of the system. In the same temperature stage, the Non-in-situ activity of sludge decreases with the decrease of temperature. It can be seen that the optimum growth temperature of sludge does not change during the cooling process, but is still around 33 C. According to Arrhenius equation, the activation energy Ea of anaerobic ammonia oxidation reaction in this experiment was 89.6 kJ/mol at 23-13 and 16.4 kJ/mol at 33-23. The lower the temperature, the greater the effect of temperature on the reaction. (3) The decrease of temperature not only changed the appearance and shape of the sludge, but also affected the system. The content of EPS in the medium-sized extracellular polymer decreases obviously at 23 C, but it increases again when the reactor temperature drops to 18 C and 13 C. Compared with the polysaccharide, the protein content fluctuates more greatly. (4) Temperature decreased, microbial community diversity showed a downward trend and a significant change at 13 ~C. The relative abundance of Phytophthora decreased from 9.04% to 9.04% after the temperature dropped from 33 ~C to 23 ~C. The microbial level showed that the sludge inoculated in this experiment contained only Candidatus Kuenenia, an anaerobic ammonia-oxidizing bacterium, and its abundance under Phytophthora was as high as that at the end of the experiment (day 199). No other anaerobic ammonia-oxidizing bacteria were found during the whole cooling process, and the dominant anaerobic ammonia-oxidizing bacteria in the reactor did not change with temperature. In addition, qPCR results showed that the copy number of AMX gene decreased first and then increased with the decrease of temperature. On the contrary, the activity value of anaerobic ammonia-oxidizing bacteria per unit cell decreased. First increase and then increase, 23 C is the key point of temperature.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703
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