生物电化学措施下潜流人工湿地反硝化性能的强化及微生物学特征

Enhancement of denitrification performance and microbiological characteristics of subsurface constructed wetland under bioelectrochemical measures

通过两种类型共4组人工湿地装置的优化对比试验,分析电解强化潜流人工湿地(E-CW)在不同电压梯度下(0.5、1.0、1.5、2.0和2.5 V)自养反硝化阶段的脱氮性能的变化及微生物群落结构特征,考察电解对湿地系统的影响。结果表明,在1.5 V电压条件下,虽然E-CW耦合系统的NH4+-N去除率低于不加电解强化措施的CW湿地装置,但是E-CW系统的反硝化速率较高,使得TN去除率高,其中E-CW3的TN平均去除率为9.52%,显著高于CW1;E-CW4的TN平均去除率为45.66%,显著高于CW2。各湿地中共发现14个优势菌门和30个优势菌目,优势菌门中的变形菌门相对丰度最高并且在各湿地中均有分布,含有许多硝化细菌和反硝化细菌,对污染物的去除起重要作用;优势菌目中的红杆菌目(Rhodobacterales),鞘氨醇菌目(Chiti-nophagales),伯克氏菌目(Burkholderiales),懒杆菌目(Ignavibacteriales),Saccharimonadales和厚壁菌门中的芽孢杆菌(Bacillus)在E-CW中的相对丰度显著高于CW,这6种细菌群属于反硝化菌,相对丰度越高,反硝化能力越强。适宜电解措施能够强化系统的自养反硝化作用,强化脱氮性能,并且也会增加群落中反硝化细菌的种类和数量,此试验的最佳外加电压为1.5 V。

This study analyzed the changes in denitrification performance and microbial community structure characteristics of electrolysis-enhanced submerged artificial wetlands(E-CW) at autotrophic denitrification stages with different voltage gradients(0.5,1.0,1.5,2.0 and 2.5 V),to examine the effects of electrolysis on the wetland system through optimized comparison experiments of two types of a total of four artificial wetland devices.The results showed that under the voltage of 1.5 V,although the NH4+-N removal rate of the E-CW coupled system was lower than that of the CW wetland device without electrolysis enhancement measures,but its denitrification rate was higher,resulting in a high TN removal rate,with the average TN removal rate of being 9.52% in E-CW3,significantly higher than that of CW1;the average TN removal rate of E-CW4 being 45.66%,significantly higher than that of CW2.A total of 14 dominant bacterial phyla and 30 dominant bacterial orders were found in each wetland,with the highest relative abundance of the dominant phylum(Proteobacteria) and its distribution in each wetland,containing many nitrifying and denitrifying bacteria,which played an important role in pollutant removal.The relative abundance of Rhodobacterales,Chitinophagales,Burkholderiales,Ignavibacteriales,Saccharimonadales and Bacillus in E-CW was significantly higher than that in CW,and these six bacterial groups belonged to denitrifying bacteria.The higher the abundance,the stronger the denitrification ability.Suitable electrolysis measures could enhance the autotrophic denitrification of the system,strengthen the denitrification performance,and also increase the species and number of denitrifying bacteria in the community,and the optimal applied voltage for this test was 1.5 V.