VA SYD, P.O. Box 191, SE-20121 Malmö, Sweden; Sweden Water Research, c/o Ideon Science Park, Scheelevägen 15, SE-22370 Lund, Sweden.
Department of Chemistry and Molecular Biology, University of Gothenburg, SE-40530 Gothenburg, Sweden; Division of Water Environment Technology, Department of Architecture and Civil Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden.
Sci Total Environ. 2020 Apr 20;714:136342. doi: 10.1016/j.scitotenv.2019.136342. Epub 2020 Jan 7.
Nitrogen removal from the mainstream of municipal wastewater with partial nitritation-anammox (PNA) would be highly beneficial with regard to the uses of energy and organic carbon. However, the challenges of process instability, low nitrogen removal rates (NRR) and unwanted aerobic nitrite oxidation need to be solved to reach large-scale implementation. Here, we have operated pilot-scale moving bed biofilm reactors (MBBRs) for mainstream treatment, together with sidestream treatment of sludge liquor from anaerobic digestors, for over 900 days to investigate process stability, reactor performance and microbial community structure at realistic conditions. The MBBR biofilm contained stable and high relative abundances of anammox bacteria (10-32%) consisting of two major Brocadia sp. populations, and several populations of aerobic ammonia-oxidising bacteria (AOB) within Nitrosomonas sp. (0.2-3.1%), as assessed by 16S rDNA amplicon sequencing. In addition, nitrite-oxidising bacteria (NOB) consisting of Nitrospira sp. (0.4-0.8%) and Nitrotoga sp. (up to 0.4%) were present. Nitrogen was removed at a peak rate of 0.66 g N m d (0.13 kg N m d) with a nitrate production over ammonium consumption of 15% by the NOB, at operation with continuous aeration at 15 °C. However, during most periods with continuous aeration, the NRR was lower (≈ 0.45 g N m d), with larger relative nitrate production (≈40%), presumably due to problems to maintain stable residual ammonium concentrations during wet-weather mainstream flows. Changing reactor operation to intermittent aeration decreased the NRR but did not help in suppressing the NOB. The study shows that with MBBRs, stable mainstream PNA can be attained at realistic NRR, but with need for post-treatment of nitrate, since effective NOB suppression was hard to achieve.
从城市废水中进行部分亚硝化-厌氧氨氧化（PNA）脱氮将具有高度的益处，因为它可以节约能源和有机碳。然而，为了实现大规模应用，还需要解决工艺不稳定、脱氮率（NRR）低和不希望出现的好氧亚硝酸盐氧化等挑战。在这里，我们在 900 多天的时间里，以实际条件运行了用于主流处理的移动床生物膜反应器（MBBR）和来自厌氧消化器的污泥液的侧流处理，以研究过程稳定性、反应器性能和微生物群落结构。MBBR 生物膜中含有稳定且相对丰度较高的厌氧氨氧化菌（10-32%），其中包含两个主要的Brocadia 种群，以及亚硝化单胞菌（Nitrosomonas sp.）中的几种好氧氨氧化菌（AOB）种群（0.2-3.1%），这是通过 16S rDNA 扩增子测序评估得出的。此外，还存在由 Nitrospira sp.（0.4-0.8%）和 Nitrotoga sp.（高达 0.4%）组成的亚硝酸盐氧化菌（NOB）。在 15°C 时连续曝气的情况下，硝酸盐的产生超过铵盐消耗的 15%，达到了 0.66 g N m d 的峰值氮去除率（0.13 kg N m d）。然而，在大多数连续曝气的时期，NRR 较低（≈0.45 g N m d），硝酸盐的相对产生量较大（≈40%），这可能是由于在湿天主流流量期间难以维持稳定的剩余铵浓度所致。改变反应器的操作方式为间歇曝气虽然降低了 NRR，但无助于抑制 NOB。该研究表明，通过 MBBR 可以在实际 NRR 下获得稳定的主流 PNA，但需要对硝酸盐进行后处理，因为难以有效抑制 NOB。
