磺胺嘧啶对纯膜MBBR氨氧化性能及氨氧化菌群的影响

通过向NH₄⁺-N质量浓度为30 mg·L⁻¹的合成废水中投加不同剂量磺胺嘧啶(SDZ)(0、1、3、5、7和10 mg·L^–1),比较了SDZ浓度对一台60 L单级纯膜移动床生物膜反应器(pure MBBR)的氨氧化速率、amoA基因丰度和氨氧化细菌(AOB)种群结构的影响,揭示了磺胺嘧啶对纯膜MBBR系统中氨氧化作用的影响机制。结果表明：1~3 mg·L^–1的SDZ显著提升了纯膜MBBR系统的氨氧化速率(P<0.05),出水${rm{NH}}_4^{+} $-N质量浓度可降低至(0.19±0.10) mg·L^–1;5~10 mg·L^–1的SDZ仍能促进${rm{NH}}_4^{+} $-N去除,但氨氧化速率变化相对平缓。相比于氨氧化古菌(AOA),AOB为纯膜MBBR氨氧化的主导者,AOB amoA基因丰度是AOA amoA基因丰度的12.2~168.5倍。1~10 mg·L^–1的磺胺嘧啶暴露显著抑制了AOB amoA基因丰度(P<0.05),但能有效刺激AOA amoA基因丰度上调(P<0.05)。高通量测序结果表明,添加磺胺嘧啶改变了AOB的种群多样性及结构,且1~3 mg·L^–1的SDZ能显著促进AOB种群多样化和亚硝化螺菌属(Nitrosospira)生长(P<0.05)。SDZ对氮源的补充、对AOB与AOA丰度占比的改变、对微生物耐药性的促进以及对AOB种群结构的干扰是其影响纯膜MBBR氨氧化过程的主要机制。

Effects of sulfadiazine on the ammonium oxidation performance and ammonia oxidizers in pure moving bed biofilm reactor

One pure moving bed biofilm reactor (pure MBBR) with working volume of 60 L was operated for treating the synthetic wastewater consisted of 30 mg·L−1 ${rm{NH}}_4^{+} $-N and different doses of sulfadiazine (SDZ) (0, 1, 3, 5, 7 and 10 mg·L−1). For this purpose, the aims of this study were to investigate the influences of influent SDZ concentrations on the ammonia oxidation rate (AOR), quantity of amoA gene and community of ammonia-oxidizing bacteria (AOB), and to reveal the mechanism regarding the ammonia oxidization of biofilm in pure MBBR system. The results showed that SDZ of 1~3 mg·L−1 significantly enhanced the AOR of pure MBBR (P<0.05), and the effluent NH4+-N concentration could be as low as (0.19±0.10) mg·L−1. SDZ of 5~10 mg·L−1 still promoted ${rm{NH}}_4^{+} $-N removal, but the change of AOR was relatively flat. Compared to ammonia-oxidizing archaea (AOA), AOB were detected as the dominator for ammonia oxidation in the pure MBBR, and AOB amoA gene abundance was 12.2 to 168.5 times as great as AOA amoA gene. The abundance of AOB amoA gene was significantly suppressed (P<0.05) due to sulfadiazine exposure (1~10 mg·L−1). In contrast, SDZ effectively stimulated the abundance of AOA amoA gene to up-regulation (P<0.05). High-throughput sequencing revealed that the population diversity and structure of AOB were strongly shifted by sulfadiazine, and SDZ of 1~3 mg·L−1 significantly promoted the diversification of AOB and Nitrosospira growth (P<0.05). The supplementation of nitrogen sources, the alteration of the abundance of AOB and AOA, the promotion of microbial resistance and the interference with the structure of the AOB population are the main impact mechanisms by sulfadiazine on ammonia oxidation process in pure MBBR.