电化学系统内Feammox/NDFO耦合工艺脱氮效能和机理

Nitrogen removal efficiency and mechanism of Feammox/NDFO coupling process in electrochemical system

针对目前Feammox/NDFO耦合工艺启动慢、脱氮效能不理想等缺陷,提出基于电化学原理强化Feammox/NDFO耦合工艺的策略.实验室内搭建生物电化学系统(BES)序批式厌氧反应器(B组),同时以不加电化学系统的普通厌氧反应器(A组)为对照组.A、B两组反应器共运行100d,分析了两反应器Feammox/NDFO耦合工艺启动过程中的脱氮效能、脱氮路径验证及种群结构组成,并探讨了BES系统Feammox/NDFO强化脱氮的机理.结果表明,实验组(B组)内NH_(4)^(+)-N去除率显著提高,第76d去除率趋于100%,TN去除率达65.83%;而对照组(A组)在第100d时,对NH_(4)^(+)-N和TN的去除率分别为50.22%和43.01%.脱氮路径验证实验结果表明,A、B组反应器内均有Feammox、NDFO、Anammox反应发生;并且B组反应器内反硝化速率明显大于A组.高通量测序结果表明,B组中铁循环脱氮功能菌中Desulfobacterota菌门的相对丰度较A组提高了2.34%;Thiobacillus和Denitratisoma丰度较A组分别提高了1.13%和0.87%.BES反应体系加速富集铁循环脱氮功能菌群,并可通过BES电极进行胞外电子转移,从而达到增强脱氮效能.

In order to improve the defects of the slow start-up and poor nitrogen removal efficiency of the Feammox/NDFO coupling process,a strategy to strengthen the start-up of Feammox/NDFO coupling process based on the principle of electrochemistry was proposed in this paper.The anaerobic sequencing batch reactor based on bio electrochemical system (BES)(named B group by authors) was built in the laboratory,and take an general anaerobic sequencing batch reactor (A group) without bio-electrochemical systems as the control group.Reactors A and B were operated for 100 days.The nitrogen removal efficiency,nitrogen removal pathway verification and microbial structure during the start-up process were analyzed,and the mechanism of enhanced denitrification in reactor B system was discussed.The results showed that the NH_(4)^(+)-N removal rate of reactor B was significantly improved,with the removal rate reaching approximate 100%and the TN removal rate reaching 65.83%on the 76th day.However,the NH_(4)^(+)-N and TN removal rates reached 50.22%and 43.01%on the 100 th day in group A.The results of nitrogen removal pathway verification experiment showed that Feammox,NDFO and Anammox reactions were all occurred in both groups A and B,and denitrification rate in group B was higher than that of group A.Compared to group A,the relative abundance of Desulfobacterota which belongs to Feammox/NDFO functional bacteria in in group B was higher than group A with 2.34%.And Thiobacillus and Denitratisoma were higher 1.1.3 and 0.87%than those of group A.BES could accelerate the enrichment of Feammox functional bacteria and denitrifying bacteria,and these bacteria could carry out extracellular electron transfer through BES electrode to enhance nitrogen removal efficiency.