一体化厌氧氨氧化反应器的优化及其稳定性研究

采用一体化厌氧氨氧化SBR反应器(120L)处理高氨氮废水,研究系统总氮去除负荷提高和稳定性的影响因素.长期试验结果表明:该一体化厌氧氨氧化SBR反应器的最大总氮去除负荷为1.1kg/(m~3·d),影响反应器运行稳定性的主要因素有:游离氨浓度、溶解氧浓度、絮体污泥和颗粒污泥相对比例等.在一体化厌氧氨氧化反应器中保持AOB和Anammox活性的相互匹配是维持系统稳定运行的关键因素.大量淘洗絮体污泥会造成氨氧化活性降低和溶解氧升高,从而引起总氮去除负荷下降.限制反应器负荷增加的主要因素有:(1)污泥随出水流失,体系污泥浓度保持恒定;(2)受溶解氧影响AOB和Anammox活性不能同时提高;(3)传质效率难以进一步提高.试验中发现总氮去除负荷和曝气量之间具有很好的相关性,反应器负荷波动时通过调整曝气量来调控反应状态,有利于一体化工艺的稳定运行.

Optimization and stability of single-stage anammox reactor

Key operational parameters of single-stage partial nitritation/anammox(PN/A) process was investigated to achieve higher nitrogen removal rate(NRR) and robustness by using a sequencing batch reactor(SBR)(120L) treating ammonia-rich wastewater. Long-term operation demonstrated that the maximum NRR of the reactor was 1.1kgN/(m³·d). The main parameters influenced the stability of the reactor were:free ammonia concentration, dissolved oxygen(DO) concentration and the relative proportions of the granules and flocs. The balance of AOB and anammox activity was the key to a robust single-stage PN/A operation. Excess discharge of floc sludge led to a decrease of ammonia oxidation rate and a high and inhibitory DO level to anammox bacteria, which eventually triggered the dramatic drop of NRR. The limiting factors of further improvement of NRR were:(1) sludge concentration stabilized due to biomass washout;(2) anammox and AOB activity could not be promoted simultaneously when further increasing DO levels;(3) mass transfer could not be further enhanced. Furthermore, NRR showed strong correlation with aeration rate in this study. Therefore, aeration rate could be an alternative regulating parameter under fluctuating influent load.