曝气条件下进水C/N对水平潜流型人工湿地脱氮效果和氮转化功能微生物丰度的影响

为提高潜流型人工湿地在低C/N条件下的污水处理效果,考察了在植物生长旺盛期曝气条件下不同C/N(0.9∶1、2∶1、4∶1)对污水的脱氮效率、微生物群落结构和功能微生物丰度的影响.结果表明:NO3-去除率为57.48％～83.19％且随C/N的增加而增加;当C/N为2和4时,可提高COD和TN的去除率,COD和TN去除...

Influence of C/N ratio on the nitrogen removal and functional microbial abundance under aeration condition in horizontal subsurface flow constructed wetlands

To improve the removal efficiency of the low C/N ratio sewage by subsurface flow constructed wetland, the influences of C/N ratios(0.9∶1, 2∶1, 4∶1) on the nitrogen removal rate, microbial community structure and functional microbial abundance under aeration condition in horizontal subsurface flow constructed wetlandsat the vigorous stage of plant growth were studied. The results were as follows: the removal rate of ${rm{NO}}_3^ - $ was 57.48%~83.19%, and increased with the increase of C/N ratio. The removal rates of COD and TN increased as the C/N ratio increased to 2 and 4, and both of them were above 80%. The gene abundance of nirK, nosZ and anammox bacterial 16S rRNA of the treatments with C/N ratios of 2 and 4 were significantly higher than that of the treatment with low C/N ratio (C/N=0.9) (P<0.05); the gene abundance of nxrA decreased as the C/N ratio increased. The bacterial species number, Shannon-Wiener index, Simpson index and Chao1 index increased with the increase of C/N ratio. The Proteobacteria and Acidobacteria were the dominant bacteria in all treatments, which accounted for 62.89%~69.66% of the total bacteria sequences. Principle coordinate analysis of bacterial communities showed that there were huge differences of microbial community among the three treatments. Thus, adjusting the C/N ratio to 2 and 4 could improve the removal efficiency of the sewage in the horizontal subsurface flow constructed wetland during the vigorously stage of plant growth. Adding carbon source and changing aeration condition could change the functional gene abundance and microbial community structure in the substrate to improve the removal efficiency of contaminants.