低温条件下全程自养脱氮工艺的磁场强化及其微生物响应机理研究

Completely autotrophic nitrogen removal over nitrite process (CANON) is considered as one of the most efficient biological nitrogen removal processes. However, the application of CANON process is limited due to the long startup period as well as low and fluctuant nitrogen removal efficiency at low temperature. Moreover, the metabolic characteristics of autotrophic microorganisms employed in CANON process are varied, which is unfavorable for the enhancement of CANON process at low temperature. In order to solve the above problems, the CANON process will be exposed to magnetic field in the proposed project, and the operation of magnetic field will be optimized to enhance the nitrogen removal efficiency and running stability of CANON process. The morphology of activated sludge and the structure of microbial communities will be measured to determine the response characteristics of microorganisms to the magnetic field at low temperature. Meanwhile, the variations of related enzyme activities and signal molecules release in the microorganisms will be detected, and the components of extracellular polymeric substance secreted by microorganisms will also be analyzed. Combined with the transformation of nitrogen in reactors, the microbial response mechanisms to magnetic field will be further explored. Based on the above research, the intensified CANON process by magnetic field will be established and used to treat actual wastewater and the performance will be evaluated. The successful completion of the proposed project will provide theoretical and technical support for the application of CANON process.

全程自养脱氮工艺（CANON）被认为是最经济便捷的污水生物脱氮路径之一，然而，该工艺在低温条件下存在启动周期长、脱氮效率低、运行不稳定等问题，限制了其工程化应用。而该工艺中不同自养微生物生长代谢特征的差异，导致低温下该工艺的强化比较困难。为解决以上问题，本项目通过向CANON工艺施加适宜的磁场，并优化磁场产生和作用方式，以强化该工艺在低温条件下的脱氮效率和运行稳定性；分析磁场作用下CANON工艺反应器内活性污泥结构、微生物形态及群落结构的变化，明确该工艺相关自养脱氮微生物对磁场强化作用的响应特征；研究磁场作用下相关微生物主要功能酶活性及微生物自我调控信号分子的变化，结合微生物胞外物质组成及反应器内物质转化过程，解析磁场作用下微生物的响应机理；并根据以上研究，建立磁场强化型CANON污水处理系统并处理实际污水，评价其运行效果。本研究成果将为CANON工艺的工程化应用提供理论和技术支持

全程自养脱氮工艺（CANON）被认为是最经济便捷的污水生物脱氮路径之一，然而该工艺在低温条件下存在启动周期长、脱氮效率低、运行不稳定等问题，限制了其工程化应用。而该工艺中不同自养微生物生长代谢特征的差异，导致低温下该工艺的强化比较困难。为解决以上问题，本项目通过向CANON工艺施加适宜的磁场，以强化该工艺在低温条件下的脱氮效率和运行稳定性；分析磁场作用下CANON工艺反应器内活性污泥结构、微生物形态及群落结构的变化，明确该工艺相关自养脱氮微生物对磁场强化作用的响应特征；研究磁场作用下相关微生物主要功能酶活性及微生物自我调控信号分子的变化，结合微生物胞外物质组成及反应器内物质转化过程，解析磁场作用下微生物的响应机理。主要研究结论如下：（1）磁场对CANON工艺的启动具有强化作用，脱氮效率得到明显增强，启动周期缩短，尤其是在低温条件下，磁场的强化作用更为明显。（2）磁场作用下污泥的生长速度明显加快，胞外聚合物中多糖和蛋白的含量及比例提高；Nitrosomonas 和Candidatus Brocadia菌属在磁场作用下得到了富集。（3）磁场作用下CANON工艺对进水pH的抗冲击能力更强。当pH低于5.5或高于8.5时，CANON工艺脱氮效果遭到破坏，但是当进水pH恢复到偏中性时，磁场作用下的反应器能更快地恢复脱氮效果。（4）磁场作用强化了短程硝化过程，亚硝酸盐积累及相关酶活性得到强化，同时厌氧氨氧化过程也得到强化，其SAA活性和血红素含量在磁场作用下显著增加，磁场能够强化Anammox工艺脱氮效果。本研究成果将为CANON工艺的工程化应用提供理论和技术支持。