ANAMMOX菌铁自养反硝化工艺的稳定性

Stability of ZVI-dependent Autotrophic Denitrification by ANAMMOX Bacteria

在非严格厌氧的连续流反应器中,通过调节进水pH、外加一定浓度的Fe2+以及定期更换新鲜铁粉这3种运行方式探讨维持厌氧氨氧化(ANAMMOX)菌利用零价铁去除硝酸盐反应体系长期稳定运行的适宜条件.结果表明,随着反应进行、受零价铁表面钝化的影响,该体系硝酸盐去除率逐渐下降,反应器难以持续运行.在一定范围内降低进水pH(5~7),或者额外投加一定量的Fe2+对改善该反应体系的稳定性效果不显著.通过定期更换新鲜铁粉的方式,可以有效提高硝酸盐去除率、增强反应器稳定性.相比对照组可稳定运行7 d,实验组可至少稳定运行60 d,硝酸盐平均去除率提高22.23%.因此,采取适宜措施保证体系内有足够具有活性的零价铁、消除零价铁钝化的不利影响,是ANAMMOX菌利用零价铁去除硝酸盐反应体系高效、稳定运行的关键.

Fe0-dependent autotrophic denitrification mediated by anaerobic ammonia oxidation( ANAMMOX) bacteria was carried out in continuous flow reactors under non-strict anaerobic conditions. Three strategies,including adjusting the influent p H,adding Fe2+,and regular renewal with fresh iron powder,were used to investigate the appropriate conditions to maintain the long-term stability of this process. The results showed that the nitrate removal efficiency declined due to Fe0 passivation over time,and this ultimately led to the reaction becoming unsustainable. Neither reducing the influent p H( within the p H range 5-7) nor adding a quantity of Fe2+had an obvious effects on the sustainability of this process. Instead,the nitrate removal efficiency and the sustainability of the reactor was enhanced significantly by regular renewal with fresh Fe0 powder. Compared with the control group( with a 7-day stable operation),the experimental setup was run steadily for at least 60 days,and the average nitrate removal efficiency was increased by 22. 23%.Consequently,maintaining an adequate amount of activated Fe0 and eliminating the adverse effects of Fe0 passivation are vital for the sustainable operation of Fe0-dependent autotrophic denitrification as mediated by ANAMMOX bacteria.