碱度对沸石序批式反应器亚硝化的影响

Effects of Alkalinity on Partial Nitrification in a Zeolite Sequencing Batch Reactor

本研究采用沸石序批式反应器(ZSBR)在常温(25℃±1℃)下实现快速稳定的亚硝化,亚硝酸盐氮积累率维持在90.0%以上,并且考察了在进水氨氮500 mg·L^(-1)时,4个不同碱度(以CaCO_3计)对ZSBR亚硝化的影响.结果表明,ZSBR实现快速亚硝化的关键是游离氨(FA)对亚硝酸盐氧化菌(NOB)的抑制作用远大于其对氨氧化菌(AOB)的抑制作用,并且经此过程转化后的含氨氮的废水,可以作为厌氧氨氧化的进水,进一步脱除水中的氨氮与总氮,当系统投加碱度(以CaCO_3计)为2 500mg·L^(-1)时,ZSBR亚硝化效果最好,平均氨氮转化率为66.7%,平均亚硝酸盐氮积累率为98.1%,平均亚硝酸盐氮产率为0.74 kg·(m^3·d)^(-1).高通量测序分析表明ZSBR长时间运行后微生物群落发生显著变化,AOB得到富集,NOB在FA的抑制作用下不断被淘洗出反应器.

Stable partial nitrification was successfully achieved in a zeolite sequencing batch reactor(ZSBR) with an excellent nitrite accumulation ratio of over 90.0%,and the effects of four alkalinity concentrations(calculated by CaCO3)on the nitritation in the ZSBR were investigated at an influent ammonia nitrogen concentration of 500 mg·L-1.The results showed that the key for the partial nitrification achieved in ZSBR was that the inhibitory effect of free ammonia(FA)on nitrite oxidizing bacteria(NOB) was much greater than that on ammonia oxidizing bacteria(AOB).Additionally,the wastewater containing ammonia nitrogen converted by this process can be used as the influent for anaerobic ammonium oxidation to further remove ammonia nitrogen and total nitrogen in wastewater.When the dosage of alkalinity was 2 500 mg·L^-1 in the ZSBR,the best nitritation efficiency was obtained with an average ammonia nitrogen conversion efficiency of 66.7%,nitrite accumulation ratio of 98.1%,and nitrite production rate of 0.74kg·(m^3·d)^-1.It was demonstrated by high-throughput sequencing analysis that significant microbial community variations occurred after a long period of operation,and these changes involved an enrichment of AOB and inhibition of NOB in the ZSBR.