In-depth knowledge on the role of pyridine as a bottleneck restricting the successful application of anammox-based process treating refractory coking wastewater remains unknown. In this study, the effect of short-term pyridine addition on a simultaneous anammox and denitrification (SAD) system fed with 25–150 mg/L pyridine was explored. The short-term operation showed that the highest total nitrogen (TN) removal efficiency was achieved at 25–50 mg/L of pyridine. As the pyridine addition increased, the contribution of the anammox pathway in nitrogen removal decreased from 99.3% to 79.1%, while the denitrification capability gradually improved. The specific anammox activity (SAA) at 150 mg/L pyridine decreased by 56.7% of the maximum SAA. The modified non-competitive inhibition model indicated that the 50% inhibitory concentration (IC₅₀) of pyridine on anammox was 84.18 mg/L and the substrate inhibition constant (K_i) of pyridine for self-degradation was 135.19 mg/L according to the Haldane model. Moreover, high-throughput sequencing confirmed the abundance of Candidatus Kuenenia as the amount of anammox species decreased, while the amounts of denitrifiers and pyridine degraders significantly increased as the pyridine stress increased. Finally, the possible pathways of nitrogen bioconversion and pyridine biodegradation in the SAD system were elucidated through metagenomic analysis and gas chromatography/mass spectrometry results. The findings of this study enlarge the understanding of the removal mechanisms of complex nitrogenous pyridine-containing wastewater treated by the SAD process.

关于吡啶作为限制基于厌氧氨氧化的工艺成功处理耐火焦化废水的瓶颈的作用的深入知识仍是未知的。在这项研究中，探讨了短期添加吡啶对同时饲喂25–150 mg / L吡啶的厌氧和反硝化（SAD）系统的影响。短期操作表明，在25–50 mg / L吡啶条件下，去除总氮（TN）的效率最高。随着吡啶添加量的增加，厌氧氨氧化途径对脱氮的贡献率从99.3％降至79.1％，而反硝化能力逐渐提高。在150 mg / L吡啶下的厌氧氨合比活性（SAA）降低了最大SAA的56.7％。修改后的非竞争性抑制模型表明，抑制浓度为50％（IC根据Haldane模型，吡啶对厌氧氨水的₅₀）为84.18 mg / L ，吡啶对自降解的底物抑制常数（K _i）为135.19 mg / L。此外，高通量测序证实，随着厌氧菌种类的减少，白念珠菌的数量增加，而反硝化剂和吡啶降解物的数量随着吡啶胁迫的增加而显着增加。最后，通过宏基因组分析和气相色谱/质谱分析结果，阐明了SAD系统中氮生物转化和吡啶生物降解的可能途径。这项研究的发现加深了对通过SAD工艺处理的含氮吡啶类复杂废水的去除机理的认识。