多级多段纯膜MBBR工艺的脱氮稳定性与微生物菌落结构分析

Analysis of denitrification stability and microbial structure in multi-stage pureMBBR process

采用宏观运行、原位小试及微观群落组成相结合的方式,探究了多级多段的纯膜MBBR工艺在工程应用中的脱氮效果及脱氮路径。结果表明,纯膜MBBR耦合改良磁加载沉淀工艺的HRT相比传统活性污泥工艺可缩短50%,且脱氮稳定性强。建议纯膜MBBR采用两级AO设计,并根据出水标准及进水波动情况,前缺氧和主好氧区分别设置2级以上以及2~4级工艺。在实际运行面临水质冲击时,通过生物膜传质梯度增加,可以显著提升污染物去除负荷,保证脱氮稳定性。在水质冲击幅度过大时,可以通过临时投加外投碳源的方式保证出水氮素稳定达标。纯膜MBBR优势硝化菌Nitrospira和Nitrosomonas,在主好氧区相对丰度分别达到3.50%~6.91%和0.65%~2.28%。Denitratisoma、Flavobacterium、Hyphomicrobium、Terrimonas和Rhodobacter等优势反硝化菌属的合计相对丰度10.85%~16.52%。缺氧区和好氧区污染物最大去除负荷与功能菌相对丰度均呈正相关。纯膜MBBR在前缺氧区提高了Candidatus Brocadia型厌氧氨氧化菌富集效率,相对丰度达到1.21%~1.56%,可为主流厌氧氨氧化的稳定实现提供参考。纯膜MBBR结合多级多段设计,具备节地效果好,抗冲击能力高等优势。

The performance and path of denitrification in a full-scale engineering of the multi-stage pure moving bed biofilm reactor(MBBR)were explored by the combined approaches of macro-scale operation,in situ small-scale test and micro-observation of microbial community composition.The results showed that compared with that of the traditional activated sludge process,the HRT of pure MBBR coupled with improved magnetic loading sedimentation process was reduced by 50%,and it had strong nitrogen removal stability.It was recommended that the pure MBBR could adopt two-stage AO design.According to the effluent standard and influent fluctuation,the front anoxic zone and the main aerobic zone should be designed with two or more stages and 2~4 stages,respectively.When facing with water quality impact during the actual operation,the pollutant removal load could be raised significantly to guarantee the nitrogen removal stability by increasing the mass transfer gradient of biofilm.When the impact of influent quality is too strong,the nitrogen in the effluent can be guaranteed to meet the standard by temporarily adding external carbon sources.The relative abundances of the dominant nitrifying bacteria Nitrospira and Nitrosomonas in the pure MBBR reached 3.50%~6.91%and 0.65%~2.28%in the main aerobic zone,respectively.The dominant denitrifying bacteria were Denitratisoma,Flavobacterium,Hyphomicrobium,Terrimonas and Rhodobacter,with a total relative abundance of 10.85%~16.52%.There was a positive correlation between the maximum pollutant removal load and the relative abundance of functional bacteria in anoxic and aerobic zones.Pure MBBR improved the enrichment efficiency of Candidatus Brocadia type anammox in the pre-anoxic zone with the relative abundance of 1.21%~1.56%,which can provide a reference for the stable realization of mainstream ANAMMOX.Multi-stage pure MBBR can fully present the advantages of MBBR treatment involving land saving and high impact resistance.