氨氮冲击负荷对硝化过程的短期影响

Short-term Influence of Ammonia Nitrogen Impact Load on Nitrification Process

为了考察氨氮冲击负荷对硝化过程的短期影响,采用SBR反应器研究了不同进水氨氮浓度下,系统硝化过程的特点以及活性污泥耗氧速率的变化。结果表明,在好氧时间不变的前提下,根据进水氨氮浓度相应地调高曝气量并不能有效消除氨氮冲击负荷对系统脱氮的影响,但DO的高低可以影响氧在水中的传质效率和微生物的硝化活性。综合考虑以上两个因素,调控好氧段的DO在2.5 mg/L左右可以在不浪费能量的情况下最大限度地提高对氨氮的去除率。在短期的氨氮冲击负荷下,活性污泥的组分变化不大,对氨氮去除率的提高主要是通过增加活性污泥的硝化速率来实现的。氨氮冲击负荷对系统的释磷和吸磷过程都会产生负面影响,造成系统除磷效果的恶化。

In order to investigate the short-term influence of ammonia nitrogen impact load on the nitrification process, a lab-scale sequencing batch reactor （SBR） was used to study the characteristics of the nitrification process and the variation of activated sludge oxygen uptake rate （OUR） under different influent ammonia nitrogen concentrations. The results show that when aerobic phase time is constant, adjusting the aeration rate according to the influent ammonia nitrogen concentration can not effectively eliminate the influence of ammonia nitrogen impact load on the nitrification process. However, DO level can determine both oxygen transfer efficiency in water and microbial nitrification activity. Comprehensively analyzing the two factors above, controlling the DO concentration in the aerobic phase at around 2.5 mg/L can improve ammonia nitrogen removal efficiency by the greatest amount without wasting energy. The composition of activated sludge changes little with short-term ammonia nitrogen impact load, and the increase of ammonia nitrogen removal rate is mainly due to the increase of sludge nitrification rate. The ammonia nitrogen impact load has a negative impact on both phosphorus release and uptake processes, resulting in deterioration of phosphorus removal efficiency.