新型短程硝化自养生物脱氮具有脱氮路径短的优点，有望解决污水厂碳源不足和曝气能耗高等运行问题。目前制约新型短程脱氮工艺实现的主要瓶颈是短程硝化过程的稳定控制，而稳定短程硝化的难点是亚硝酸盐氧化菌的选择性抑制。如何实现不同类别的氨氧化菌与亚硝酸盐氧化菌的选择性调控，是近年来短程硝化探索的热点和难点问题。因此，本论文针对低碱度条件下序批式反应器中活性污泥短程硝化过程的微生物群落调控方法、发生机制及模型预测开展了深入研究工作，旨在为短程硝化脱氮在实际污水中的技术开发和工程应用提供支持。首先，论文探究了低碱度进水条件下短程硝化的发生条件，研究了低pH（4.0～5.0）条件下的短程硝化策略，在悬浮活性污泥中实现了相对较低氨氮浓度废水（100 mg NH4+-N?L−1）短程硝化的长期稳定运行。研究发现在酸性短程硝化过程中，Nitrosomonas和Nitrosospira这两种氨氧化菌可以实现合作共存，并随着pH逐步降低，Ca. Nitrosoglobus菌属逐渐成为主要的耐酸、耐游离亚硝酸抑制的氨氧化菌。在建立上述酸性短程硝化的基础上，论文采用宏基因组测序组装方法，进一步揭示了短程硝化微生物群落代谢机制，并以低强度间歇超声实现短程硝化过程为例，对比了生化抑制和物理抑制策略下短程硝化菌群代谢机制的差异，发现细胞信号传导、能量转化和脂质代谢在氨氧化菌的耐受和亚硝酸盐氧化菌的抑制中发挥重要作用。在此基础上，本研究进一步围绕短程硝化过程微生物群落动态演替的特征展开研究，在传统活性污泥动力学模型的基础上，拓展建立了耦合微生物群落动态演替过程的动力学模型，以描述低碱度环境条件驱动的短程硝化发生过程及其微生物群落演替驱动机制。模型通过短期序批实验对模型参数进行校准，校准模型实现了连续500多天的短程硝化出水氮浓度动态变化的准确模拟，并可模拟不同pH条件下反应器内硝化微生物群落组成随运行时间的动态演替过程。最后，基于生化反应动力学与微生物群落动态演替驱动关系耦合模型，建立了适用于不同进水浓度等更广泛运行条件下的短程硝化过程发生模型，模拟预测了不同条件下实现短程硝化的控制条件，获得短程硝化稳定发生的适用控制策略和条件范围。验证结果表明，较高碱度的进水难以基于原位游离亚硝酸实现短程硝化，而低碱度条件下可以驯化出耐酸氨氧化菌，从而实现低氨氮浓度下的高效稳定短程硝化。
The short-cut autotrophic nitrogen removal technology, as a forward-looking approach, promises to save more than half of the oxygen and all of the organic matter requirement, and greatly reduce the amount of residual sludge. This results in significant cost savings and enhanced energy efficiency. However, the main challenge hindering the implementation of short-cut nitrogen removal process lies in the stable operation of partial nitritation (PN), specifically the selective inhibition of nitrite-oxidizing bacteria (NOB), which has remained a persistent issue in recent years. Therefore, this thesis undertook comprehensive research on microbial community regulation strategies, underlying mechanisms, and predictive modeling to achieve PN in sequencing batch reactors (SBRs) under low alkalinity conditions, aiming to support the technological development and practical application of PN in wastewater treatment.Initially, the thesis investigated the conditions conducive to PN under low alkalinity influent and explored PN strategies under low pH (4.0~5.0) conditions. Long-term stable PN operation was achieved in SBR suspended activated sludge with relatively low ammonia-nitrogen concentration wastewater (100 mg NH4+-N?L−1). The study revealed cooperative coexistence of two ammonia-oxidizing bacteria (AOB) species, Nitrosomonas and Nitrosospira, during acidic PN realization in the SBR. Additionally, through gradual pH reduction, a novel genus, Ca. Nitrosoglobus, was domesticated and emerged as the predominant acid- and free nitrous acid (FNA)-tolerant AOB.Subsequently, leveraging metagenomic techniques, this thesis delved into the metabolic mechanisms of nitrifying microbial communities, comparing differences in metabolic responses under low pH chemical inhibition and ultrasound-induced physical stimulation. It was found that signaling processes, energy conversion, and lipid metabolism play pivotal roles in AOB tolerance and NOB inhibition.Building upon this foundation, the study characterized the dynamic succession of microbial communities in PN and developed a model that couples microbial community dynamics with traditional activated sludge kinetic models to describe PN processes. Model parameters were calibrated using short-term batch tests, enabling accurate simulation of NH4+, NO2?, and NO3? concentrations in the reactor effluent and dynamics of nitrifying microbial communities over 500 days.Finally, the model was applied to predict PN under a wider range of operating conditions and validated against long-term nitrification and partial nitrification processes. The results confirmed the difficulty of achieving PN based on in situ FNA under high alkalinity conditions, while demonstrating that efficient and stable PN can be attained at low ammonia concentrations under low alkalinity conditions.
