低DO与化学控制相结合的半亚硝化运行

针对厌氧氨氧化工艺（ANAMMOX）的进水需求以及污水中氮素的存在形态，增强前置半亚硝化工艺的运行稳定性是十分有必要的。研究发现：在温度（30±1）℃、进水pH在8.0以上、DO在0.3 mg·L-1左右、HRT=8 h的情况下；逐步增加进水氨氮（NH4+-N）与碳酸氢盐浓度，经过19 d成功启动亚硝化反应（以亚硝硝酸盐积累率达到50%为限）；为了进一步提升亚硝酸盐积累率，间歇投加5 mmol·L-1氯酸钾，后又改加联氨作为硝化反应的选择性抑制剂，经过大约90 d的反复调试运行，使得出水中NH4+-N与亚硝态氮（NO2--N）的摩尔比近似1：1，基本符合厌氧氨氧化工艺进水需求。通过Miseq测序结果发现：氨氧化菌（AOB）在添加氯酸钾之后，已经成为绝对优势菌种，所占比例为54.99%；在添加联氨之后，AOB所占比例能够达到63.92%，其中包括Nitrosomonas sp和Nitrosomonas europaea这两种亚硝化菌；只有痕量亚硝酸盐氧化菌（NOB）的存在。

Combination of low DO and chemical control in the operation of semi-nitrification

The purpose of this work is to improve the inflow conditions of anaerobic ammonium oxidation (Anammox) and nitrogen found in sewage, as it is necessary to strengthen the running stability of the front partial-nitrification process. This study shows that the nitrification reaction can be initiated successfully by gradually increasing the concentration of NH4+-N and HCO3- after 19 days, at the temperature of 30±1 ℃, with an inflow pH above 8.0, the DO at about 0.3 mg·L-1, and an operation time of HRT=8 h (within the limit of the accumulated NO2--N accounts for 50% of NO-x-N). In order to increase the rate of nitrification further, 5 mmol·L-1 KClO3 was added intermittently, followed by the addition of hydrazine, which acted as a selective inhibitor of nitration. Finally, a mole ratio of about 1:1 of ammonia nitrogen and nitrate was achieved in the effluent after repeated adjustment and operation for about 90 days, which met most of the requirements of the inflow condition in the Anammox. The PCR-Miseq results demonstrated that ammonia-oxidizing bacteria become an absolutely dominant strain with a proportion of 54.99% after adding KClO3. However, when hydrazine is added, the proportion of AOB could reach 63.92%. Moreover, the results suggest that the bacterium mainly consists of Nitrosomonas sp and Nitrosomonas europaea and a trace of nitrite-oxidizing bacteria.