不同挂膜启动方式对复合硫填料自养脱氮效果的影响

Influence of Different Start‑up Mode on the Effect of Autotrophic Denitrification of Composite Sulfur Fillers

为确定硫自养反硝化技术在工程应用中合适的启动方式,对比了变滤速接种挂膜、变滤速自然挂膜和固定滤速自然挂膜三种不同的挂膜方式对脱氮效果的影响。结果表明,接种挂膜在实际工程应用中没有显著优势,变滤速自然挂膜法的脱氮效果最好,其最大脱氮负荷为0.81 kg/(m^(3)·d)。通过分析pH、DO和SO_(4)^(2-)等参数的变化情况发现,挂膜过程会使出水pH降低,进水DO过高会抑制脱氮过程,一些好氧菌可能会利用溶解氧将硫单质氧化为SO_(4)^(2-),使SO_(4)^(2-)平均增加量高于理论值。采用高通量测序手段对系统内微生物群落结构特征进行了分析,在属水平上反应器中进行硫自养反硝化的优势菌群有硫杆菌属(Thiobacillus)和热单胞菌属(Thermomonas),相对丰度分别为6.38%和3.86%,与二沉池回流污泥的微生物群落结构相比存在明显的驯化过程。

In order to find a suitable start‑up method for sulfur autotrophic denitrification technology in engineering applications,the effects of three different start‑up mode on the denitrification effect were compared,which included variable filtration rate inoculated biofilm formation,variable filtration rate natural biofilm formation and fixed filtration rate natural biofilm formation.The results showed that the inoculated biofilm formation had no significant advantages in engineering applications.The variable filtration rate natural biofilm formation had the best denitrification effect,and its maximum denitrification load was 0.81 kg/(m^(3)·d).By analyzing the changes of parameters such as pH,dissolved oxygen and SO_(4)^(2-),it was found that the process of biofilm formation would reduce the effluent pH,and high DO in the influent would inhibit the denitrification process.Some aerobic bacteria may use dissolved oxygen to oxidize elemental sulfur to SO_(4)^(2-),so that the average increase of SO_(4)^(2-)was higher than the theoretical value.The characteristics of the microbial community structure in the system were analyzed by high‑throughput sequencing.The dominant bacteria at the genus level for sulfur autotrophic denitrification in the reactor were Thiobacillus and Thermomonas,with relative abundances of 6.38%and 3.86%,respectively.Compared with the reflux sludge from secondary sedimentation tank,the microbial community structure in the reactor had an obvious domestication process.