在当前的全球经济发展趋势和政治格局背景下，我国提出“力争于2030年前达到碳达峰，2060年前达到碳中和”的目标。为此，寻求一种绿色经济的污水处理工艺已十分迫切。厌氧氨氧化(Anammox)是当前已知的最为经济的生物脱氮技术之一，具有无需外加有机碳源、无需曝气、污泥产量低等优势。

        厌氧氨氧化菌(AnAOB)发挥生物脱氮作用需要同时存在铵盐态氮(NH₄⁺-N)、亚硝酸盐态氮(NO₂^--N)，获得稳定的NO₂^--N电子受体是实现Anammox的关键，因此，部分亚硝化-厌氧氨氧化(PN/A)耦合工艺受到了广泛关注。Anammox作为耦合工艺中不可缺失的一部分，有学者尝试利用新式调控手段促进该反应过程，投加纳米零价铁(nZVI)具有易操作、对环境污染少等特点，在水污染治理方面受到了广泛重视。同时，无机碳源(IC)不仅参与Anammox过程，还会对调控过程产生影响，因此有必要讨论进水IC浓度不同时，nZVI投加量对Anammox工艺的影响。

        针对以上问题，本文采用添加选择性硝化抑制剂-NaClO₃、改变曝气量的方式实现PN工艺的启动及稳定运行；接种生物膜启动连续流Anammox反应器，通过修正的Stover-kincannon模型预测Anammox反应器最大脱氮潜能；利用高通量测序、扫描电镜技术对比启动前后微生物种群特性；将稳定运行的PN、Anammox工艺串联考察组合工艺对氮素的去除效果；设置进水IC/TN分别为0.24、0.05，考察nZVI投加量对Anammox脱氮效果的影响，并分析其作用机理，结论如下：

        （1）为实现NO₂^--N积累，向PN反应器投加NaClO₃，投加量为6 mmol/L时，NH₄⁺-N去除率为88.89%，NO₂^--N积累率为95.44%，成功实现NO₂^--N的积累。实现NO₂^--N积累后，采用曝气量控制氨氧化过程，当曝气量为0.3 L/min时，出水NH₄⁺-N平均浓度为53.92 mg/L，出水NO₂^--N平均浓度为57.63 mg/L，出水NO₂^--N/NH₄⁺-N基本符合Anammox进水要求。

        （2）Anammox反应器经过78 d运行达到稳定状态，NH₄⁺-N、NO₂^--N与TN去除率分别达到99.24%、99.06%与84.76%。Stover-kincannon模型预测出Anammox反应器的最大容积负荷为0.1974 kg/(m³·d)，运行78 d时的容积负荷为预测值的52.68%，有较大的提升空间。扫描电镜结果显示：启动前的细菌形态主要为杆菌，启动后的细菌形态主要为球菌。

        （3）高通量测序结果表明：对于PN工艺，接种污泥的优势菌属之一为硝化螺旋菌(Nitrospira)，占比为3.25%，启动成功后，亚硝化毛杆菌(Nitrosomonas)为优势菌属之一，占比为14.68%，是AOB常见的菌属；对于Anammox工艺，接种生物膜中属于AnAOB的是斯图加特库氏菌(Candidatus Kuenenia)，占比为1.05%，成功启动后，属于AnAOB的是布罗卡地菌(Candidatus Brocadia)、unclassified_Candidatus_Brocadiaceae，占比分别为13.00%、2.25%，出现运行环境改变导致菌属发生变化的现象。

        （4）PN、Anammox工艺稳定运行后，将两者串联形成PN/A耦合工艺，串联初期未对PN工艺的出水进行pH调节，导致后续Anammox工艺对TN去除效果变差，去除率逐渐降低至62.48%，将PN工艺出水pH调节至7.6左右，脱氮效果逐渐恢复至81.96%。

        （5）当Anammox工艺进水IC/TN为0.24，投加适量nZVI可以提高TN去除率，而过量nZVI会使TN去除率降低；同时，根据典型周期内氮素变化可知，适量nZVI可以提高基质利用速率。

        （6）当Anammox工艺进水IC/TN为0.05，适量nZVI能减弱IC不足导致的TN去除率下降问题；同时，进水IC减少，投加适量nZVI对基质利用速率的提高幅度更大。高通量测序结果表明：IC减少，Candidatus Brocadia占比由8.16%减少至7.13%，unclassified_Candidatus_Brocadiaceae占比由34.92%升高至39.08%，表明该菌属对铁有依赖性，投加nZVI能使该菌种得到富集且适应IC不足的环境。

        Against the backdrop of current global economic development trends and political landscape, China has proposed the goal of achieving carbon peak by 2030 and carbon neutrality by 2060. Therefore, it is urgent to seek a green and economical sewage treatment process. Anammox is one of the most economical biological nitrogen removal technologies known at present, which has the advantages of no additional organic carbon source, no aeration, low sludge production, etc.

        Anaerobic ammonia oxidizing bacteria (AnAOB) need ammonium salt nitrogen (NH₄⁺-N) and nitrite nitrogen (NO₂^--N) to play the role of biological nitrogen removal. Obtaining a stable NO₂^--N electron acceptor is the key to realizing Anammox. Therefore, Partial Nitrification-Anammox system (PN/A) coupling process has attracted extensive attention. Anammox is an indispensable part of the coupling process, and some scholars have attempted to use new regulatory methods to promote the reaction process. Adding nano zero valent iron (nZVI) has the characteristics of easy operation and low environmental pollution, and has received widespread attention in water pollution control. At the same time, inorganic carbon sources (IC) not only participate in the Anammox process, but also have an impact on the regulatory process. Therefore, it is necessary to discuss the impact of nZVI dosage on the Anammox process with different influent IC concentrations.

        In response to the above issues, this article adopts the method of adding selective nitrification inhibitor NaClO₃ and changing the aeration rate to achieve the start-up and stable operation of the PN process; Inoculate biofilm to start a continuous flow Anammox reactor, and predict the maximum denitrification potential of the Anammox reactor using a modified Stover-kincanon model; Compare the microbial population characteristics before and after startup using high-throughput sequencing and scanning electron microscopy techniques; Connect the stable running PN and Anammox processes in series to investigate the combined process's nitrogen removal effect; Set the influent IC/TN to 0.24 and 0.05, respectively, to investigate the effect of nZVI dosage on Anammox denitrification effect, and analyze its mechanism. The conclusion is as follows:

        (1) To achieve NO₂^--N accumulation, NaClO₃ was added to the PN reactor at a dosage of 6 mmol/L, resulting in the NH₄⁺-N removal rate of 88.89% and the NO₂^--N accumulation rate of 95.44%. The accumulation of NO₂^--N was successfully achieved. After realizing the accumulation of NO₂^--N, the aeration rate is used to control the Ammoxidation process. When the aeration rate is 0.3 L/min, the average concentration of effluent NH₄⁺-N is 53.92 mg/L, and the average concentration of effluent NO₂^--N is 57.63 mg/L. The effluent NO₂^--N / NH₄⁺-N basically meets the requirements of Anammox influent.

        (2) The Anammox reactor reached a stable state after 78 days of operation, with NH₄⁺-N, NO₂^--N, and TN removal rates reaching 99.24%, 99.06%, and 84.76%, respectively. The Stover-Kincanon model predicts that the maximum volumetric load of the Anammox reactor is 0.1974 kg/(m³·d), and the volumetric load after 78 days of operation is 52.68% of the predicted value, indicating significant room for improvement. The scanning electron microscopy results showed that the pre startup bacterial morphology was mainly Bacillus, while the post startup bacterial morphology was mainly Staphylococcus.

        (3) The results of high-throughput sequencing showed that for the PN process, one of the dominant bacteria for sludge inoculation was Nitrospira, accounting for 3.25%. After the successful startup, Nitrosomonas was one of the dominant bacteria, accounting for 14.68%, which was common in AOB; For Anammox process, Candidatus Kuenenia, accounting for 1.05%, belongs to AnAOB in the inoculated biofilm. After successful startup, Candidatus Brocadia and unclassified_Candidatus_Brocadiaceae, accounting for 13.00% and 2.25% respectively, showed changes in the operating environment leading to changes in the AnAOB genus.

        (4) After the stable operation of the PN and Anammox processes, the two were connected in series to form a PN/A coupling process. At the initial stage of the series connection, the pH of the effluent from the PN process was not adjusted, resulting in poor TN removal efficiency in the subsequent Anammox process. The removal rate gradually decreased to 62.48%. The pH of the effluent from the PN process was adjusted to around 7.6, and the denitrification effect gradually recovered to 81.96%.

        (5) When the influent IC/TN of Anammox process is 0.24, adding an appropriate amount of nZVI can improve the TN removal rate, while excessive nZVI will reduce the TN removal rate; Meanwhile, according to the nitrogen changes during typical cycles, an appropriate amount of nZVI can improve the substrate utilization rate

        (6) When the influent IC/TN of Anammox process is 0.05, an appropriate amount of nZVI can alleviate the problem of TN removal rate decrease caused by insufficient IC; At the same time, the influent IC decreases, and the addition of an appropriate amount of nZVI increases the substrate utilization rate even more significantly. The high-throughput sequencing results showed that the IC decreased, and the proportion of Candidatus Brocadia decreased from 8.16% to 7.13%, unclassified_Candidatus_Brocadiaceae increased from 34.92% to 39.08%, indicating that the genus is iron dependent. Adding nZVI can enrich the genus and adapt to IC deficient environments.