海水养殖废水序批式生物膜反应器构建及其脱氮性能与微生物群落结构解析

Construction of sequential batch biofilm reactor in marine aqua⁃culture wastewater and its nitrogen removal performance and microbial community structure analysis

【目的】评估不同盐度条件下序批式反应器(SBR)和序批式生物膜反应器(SBBR)的氨氮去除效果及其表面生物膜特性,探究高盐条件下能实现高效去除氨氮的微生物菌群结构,为海水养殖过程中微生物高效硝化技术的开发与应用提供参考依据。【方法】SBR和SBBR接种相同的活性污泥后,模拟海水养殖废水处理,并在未加盐的条件下首次启动,保持15 d的稳定运行后将反应器内的盐度逐渐增加到1.0%、2.0%、3.0%和4.0%,然后通过扫描电子显微镜—能谱分析、N-(1-萘基)-乙二胺光度法、纳氏试剂光度法和宏基因组测序分析对每个盐度阶段不同反应器的硝化性能、微生物群落结构及代谢基因丰度变化进行评价。【结果】SBR硝化性能受盐度的影响较明显,在高盐(3.0%和4.0%)条件下的氨氮去除率仅为43.18%和37.97%;盐度变化对SBBR的硝化功能无明显影响,在4.0%的高盐条件下仍能实现高效硝化(氨氮去除率在98.00%以上)。相对于SBR,SBBR中微生物群落的物种丰度及多样性更高、群落结构相对更稳定,尤其是冰冷杆菌属(Gelidibacter)和亚硝化单胞菌属(Nitrosomonas)的相对丰度不受盐度变化的影响;副球菌属(Paracoccus)、陶厄氏菌属(Thauera)及假单胞菌属(Pseudomonas)等反硝化细菌在SBBR中也具有较高的相对丰度。相对于SBR,反硝化关键基因norB和nosZ在SBBR中的丰度更高,且具有更强的协同效应。【结论】以海绵生物膜填料为载体的SBBR能在高盐条件下实现短期启动硝化脱氮及维持微生物群落结构稳定性,促使SBBR存在多种脱氮途径,同时表现出更强的脱氮基因协同效果。SBBR的脱氮效果较传统活性污泥法有明显提升,为高盐条件下海水养殖废水脱氮处理提供了有效的解决方案。

【Objective】Evaluation of ammonia nitrogen removal efficiency and biofilm characteristics in sequential batch reactor(SBR)and sequential batch biofilm reactor(SBBR)under varying salinity conditions was conducted,mi‐crobial community structure for efficient ammonia nitrogen removal in high-salinity conditions was investigated to pro‐vide reference for the development and application of high-efficiency microbial nitrification technology in marine aquacul‐ture.【Method】SBR and SBBR were used to inoculate the same activated sludge in order to simulate the treatment condi‐tions of mariculture wastewater.Both sets of reactors were initially started without the addition of salt and operated steadily for 15 d.Subsequently,the salinity in the reactors was gradually increased to 1.0%,2.0%,3.0%and 4%.The ni‐trification performance,microbial community structure and metabolic gene abundance of each reactor stage were evalua-ted using scanning electron microscopy-energy dispersive spectroscopy,N-(1-naphthyl)-ethylenediamine photometry,Nessler’s reagent photometry and metagenomic sequencing analysis.【Result】The salinity greatly affected the nitrification performance of SBR.In a high salt environment(3.0%and 4.0%),the removal rate of ammonia nitrogen was only 43.18%and 37.97%for SBR.The salinity change had no obvious effect on the nitration function of SBBR,SBBR could still achieve efficient nitrification with a removal rate of ammonia nitrogen of 98.00%even at a salinity of 4.0%.Com‐pared to SBR,the microbial community in SBBR demonstrated higher species abundance and diversity,with a relatively more stable community structure.Notably,the relative abundances of Gelidibacter and Nitrosomonas were not affected by salinity changes.Denitrification bacteria such as Paracoccus,Thauera and Pseudomonas also exhibited higher relative abundance in SBBR.The key denitrification genes norB and nosZ showed higher abundance in SBBR compared to SBR,and showed stronger synergistic effects.【Conclusion】SBBR using sponge biofilm carriers can achieve short-term nitrifica‐tion and nitrogen removal startup under high-salinity conditions,while maintaining the stability of microbial community structure.This facilitates multiple nitrogen removal pathways and enhances the synergistic effects of nitrogen removal genes.Compared to conventional activated sludge processes,the denitrification performance of SBBR is greatly im‐proved,offering an effective solution for nitrogen removal in seawater aquaculture wastewater under high-salinity condi‐tions.