Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, USA.
Chemosphere. 2021 Oct;281:130729. doi: 10.1016/j.chemosphere.2021.130729. Epub 2021 Apr 30.
Anammox process has been widely applied in the wastewater nitrogen removal for its high rate and low cost. However, few researches reported the process potential in treating low-strength nitrogen wastewater. In this study, a sequencing batch reactor (SBR) was taken to explore the feasibility of low-strength nitrogen wastewater treatment by anammox process in theory and practice. The practical operation indicated that the effluent with satisfactory quality (1.90 ± 0.70 mg-TN·L) could be achieved, when the SBR was fed with low-strength nitrogen influent (6.20 ± 0.45 mg-NH-N·L and 7.96 ± 0.59 mg-NO-N·L). The hydraulic retention time (HRT), nitrogen removal efficiency, nitrogen removal rate (NRR) and hydraulic loading rate of SBR were 5.42 h, 86.5%, 0.054 kg-N·m·d and 4.43 m·m·d during the 79-day operation, respectively. The theoretical analysis revealed the potential of anammox SBR. When SBR is stably operated, the maximum NRR would be 0.062 kg-N·m·d if the effluent nitrogen was required to be as low as 3 mg·L. The NRR value is feasible for engineering. However, considering the lower specific substrates utilization rate in practice, the maximum stable NRR was calibrated and found inefficient afterwards. In order to improve the potential of anammox process, the reactors without back mixing and with periodic bioaugmentation should be taken in priority for the engineering applications. In particular, the bioaugmentation frequency and single addition amount were calculated as 7 d and 0.3 g-VSS·L, respectively. The results may provide guidance for the development of high-efficient and stable nitrogen removal process under low-strength condition.
厌氧氨氧化工艺因其高效低耗而被广泛应用于废水脱氮。然而，很少有研究报道该工艺在处理低浓度氮废水方面的潜力。本研究采用序批式反应器（SBR）从理论和实践两方面探索了厌氧氨氧化工艺处理低浓度氮废水的可行性。实际运行结果表明，当 SBR 进水为低浓度氮源（6.20±0.45 mg-NH-N·L 和 7.96±0.59 mg-NO-N·L）时，可获得出水水质良好（1.90±0.70 mg-TN·L）。SBR 的水力停留时间（HRT）、脱氮效率、脱氮速率（NRR）和水力负荷分别为 5.42 h、86.5%、0.054 kg-N·m·d 和 4.43 m·m·d。在 79 天的运行过程中，通过理论分析揭示了厌氧氨氧化 SBR 的潜力。当 SBR 稳定运行时，如果出水氮浓度要求低至 3 mg·L，最大 NRR 将达到 0.062 kg-N·m·d。该 NRR 值在工程上是可行的。然而，考虑到实际中较低的特定基质利用率，对最大稳定 NRR 进行了标定，发现其效率较低。为了提高厌氧氨氧化工艺的潜力，在工程应用中应优先采用无回流和定期生物强化的反应器。特别是，生物强化的频率和单次添加量分别计算为 7 d 和 0.3 g-VSS·L。研究结果可为低浓度条件下高效稳定脱氮工艺的开发提供指导。
