D-A^(2)O工艺高效脱氮及有机物降解机理研究

Efficient Denitrification and Organic Matter Degradation Mechanism of D-A^(2)O Process

D-A^(2)O是基于A^(2)O工艺设计的双系列厌氧/缺氧交替运行污水处理工艺,具有较为显著的脱氮除磷及有机物去除效果。为了查明D-A^(2)O工艺高效脱氮及有机物降解的原因,采用宏基因组学技术,利用amoA基因及pufM基因对D-A^(2)O、A^(2)O两种工艺活性污泥中脱氮及降解有机物的微生物群落结构进行检测分析。结果表明,在科水平上,两种工艺共检测到含amoA基因的微生物有亚硝化单胞菌、变形菌、假单胞菌、莫拉氏菌等8种,其中亚硝化单胞菌科以及β-变形菌为优势菌种。亚硝化单胞菌在D-A^(2)O好氧池中的比例(3.24%)是A^(2)O(1.48%)的2.2倍;β-变形菌在D-A^(2)O好氧池中的比例(0.21%)是A^(2)O(0.11%)的2倍;而假单胞菌、丛毛单胞菌仅在D-A^(2)O工艺中被发现。可见,D-A^(2)O系统内具有更为丰富的脱氮微生物种类及更高的种群密度。另外,两种工艺中共检测到含pufM基因的微生物为变形菌、慢生根瘤菌、嗜甲基杆菌等8种,其中变形菌及慢生根瘤菌为优势菌种。慢生根瘤菌在D-A^(2)O好氧池中的比例(8.52%)是A^(2)O(5.51%)的1.55倍,且D-A^(2)O工艺中的嗜甲基杆菌、鞘脂单胞菌、醋杆菌、伯克霍尔德氏菌、红环菌、着色菌种群数量均高于A^(2)O工艺中相应工艺单元。此外,通过对α多样性及物种丰度热图进行分析,进一步说明了D-A^(2)O工艺具有更为丰富的微生物物种多样性,具有更高的脱氮及有机物降解能力。

D-A^(2)O process is a dual-series alternating anaerobic/anoxic sewage treatment process modified by A^(2)O process,which has significant effects on nitrogen and phosphorus removal and organic matter degradation.To investigate the reasons for efficient denitrification and organic matter degradation in D-A^(2)O process,amoA gene and pufM gene were employed to detect and analyze community structure of denitrification and organic matter degradation microorganisms in activated sludge of D-A^(2)O and A^(2)O processes.At family level,8 species of microorganisms containing amoA gene in the two processes were detected,including Nitrosomonas,Proteobacteria,Pseudomonas and Moraxella,among which Nitrosomonas and Betaproteobacteria were the dominant species.The proportion of Nitrosomonadaceae in the aerobic tank of D-A^(2)O process(3.24%)was 1.2 times higher than that of A^(2)O process(1.48%),the proportion of Betaproteobacteria in the aerobic tank of D-A^(2)O process(0.21%)was twice as high as that of A^(2)O process(0.11%),and Pseudomonadaceae and Comamonadaceae were only detected in the D-A^(2)O process.Therefore,the D-A^(2)O system had more abundant species of denitrifying microorganisms and higher population density.In addition,a total of 8 species of microorganisms containing pufM gene in the two processes were detected,such as Proteobacteria,Bradyrhizobiaceae,Methylobacteriaceae and so on,among which Proteobacteria and Bradyrhizobiaceae were the dominant species.The proportion of Bradyrhizobiaceae in the aerobic tank of D-A^(2)O process(8.52%)was 1.55 times as high as that of A^(2)O process(5.51%),and the number of Methylobacteriaceae,Sphingomonadaceae,Cetobacteraceae,Burkholderiales,Hodobacteraceae and Hromatiaceae in the D-A^(2)O process was higher than that in the corresponding tank of the A^(2)O process.Furthermore,analysis ofαdiversity and species abundance heatmap further indicated that D-A^(2)O process had more abundant microbial species diversity and higher nitrogen removal and organic matter degradation ability.