The primary objectives of this study were to identify the effectiveness of hydrazine on partial nitrification in a sequencing batch reactor when treating low-strength ammonia wastewater and to investigate its impact mechanism. Partial nitrification was successfully initiated and maintained by dosing with hydrazine, and the short- and long-term effects of hydrazine on partial nitrification and microbial bioactivity were investigated. The results showed that dosing with a moderate amount of hydrazine improved the nitrite accumulation rate with little effect on the ammonia conversion rate. Both the short- and long-term tests showed the optimum hydrazine dosage was 7.5 mg/L. In the long-term tests, dosing with 7.5 mg/L of hydrazine led to an ammonia conversion rate and nitrite accumulation rate of 99.10% and 93.24%, respectively. The change in the mixed liquid suspended solids (MLSS) and mixed liquid volatile suspended solids (MLVSS) in the long-term tests showed that, although dosing with hydrazine influenced the biochemical activity of the sludge, the MLVSS/MLSS increased after an initial decrease. High-throughput analysis showed that Thauera, Nitrosomonas, and Denitratisoma were the dominant bacteria in the system dosed with 7.5 mg/L of hydrazine, which may explain the high nitrite accumulation. Analysis of the mechanism showed that nitrite-oxidizing bacteria were more inhibited by hydrazine dosing than ammonium-oxidizing bacteria.

中文翻译：

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联氨对低浓度氨废水保持稳定的部分硝化策略

本研究的主要目的是确定在序批式反应器中处理低浓度氨废水时肼对部分硝化的有效性，并研究其影响机制。通过加入肼成功启动和维持了部分硝化作用，并研究了肼对部分硝化作用和微生物生物活性的短期和长期影响。结果表明，加入适量的肼提高了亚硝酸盐的积累率，而对氨转化率的影响不大。短期和长期试验均表明肼的最佳用量为 7.5 mg/L。在长期试验中，添加 7.5 mg/L 联氨的氨转化率和亚硝酸盐积累率分别为 99.10% 和 93.24%。长期试验中混合液体悬浮物（MLSS）和混合液体挥发性悬浮物（MLVSS）的变化表明，虽然投加肼会影响污泥的生化活性，但MLVSS/MLSS在初始下降后有所增加。 . 高通量分析表明Thauera、Nitrosomonas和Denitratisoma是该系统中的优势菌，在 7.5 mg/L 的联氨剂量下，这可能解释了亚硝酸盐的高积累。机理分析表明，肼给药对亚硝酸盐氧化菌的抑制作用大于氨氧化菌。