COD对连续流厌氧氨氧化混菌体系氮素转化和菌群结构的影响

Effect of COD on Nitrogen Conversion and Microbial Community Structure in a Continuous Flow Anaerobic Ammonia Oxidation Mixed Bacterial System

为了研究COD对厌氧氨氧化混菌体系氮素转化和菌群结构的影响,以MBBR工艺启动两个厌氧氨氧化(Anammox)对比反应器。分为3个阶段逐步将进水总氮(TN)从40 mg·L^(-1)提高到580 mg·L^(-1),控制DO在0.1±0.05 mg·L^(-1),水力停留时间(HRT)从30 h缩小到24 h,R1(长期投加50 mg·L^(-1)COD)TN去除率从27.99%提高到85.52%;R2(未投加COD)TN去除率从12.45%提高到73.81%。16s RNA测序表明,进水投加50 mg·L^(-1)COD的R1,厌氧氨氧化菌的相对丰度为39.50%,R2中为42.08%。氮素转化分析,添加COD的R1对比R2有更低且稳定短程硝化,加强了Anammox反应,其原因可能是COD消耗了系统中的溶解氧抑制了硝化作用,为厌氧氨氧化提供了良好的厌氧环境。提出的实验说明了COD的添加对Anammox反应器脱氮效率有促进作用,但其带来的异养菌增殖会使厌氧氨氧化菌的相对丰度降低。

In order to study the effect of COD on nitrogen conversion and microbial community structure in Anammox mixed bacterial system,two Anammox comparative reactors were initiated using the MBBR process.They were divided into three stages to gradually increase the total nitrogen(TN)of the influent from 40 mg·L^(-1) to 580 mg·L^(-1),the DO was controlled at 0.1±0.05 mg·L^(-1),the hydraulic retention time(HRT)was reduced from 30 h to 24 h,and the TN removal rate of R1(long-term addition of 50 mg·L^(-1) COD)increased from 27.99%to 85.52%;The removal rate of R2(without adding COD)and TN increased from 12.45%to 73.81%.16s RNA sequencing showed that the relative abundance of anaerobic ammonia oxidizing bacteria(Candidatus Brocadia)was 39.50%in R1 with 50 mg·L^(-1) COD added to the influent,and 42.08%in R2.Nitrogen conversion analysis showed that R1 with added COD had lower and stable short-term nitrification compared to R2,which strengthened the Anammox reaction.The reason was that COD consumed dissolved oxygen in the system and inhibited nitrification,providing a good anaerobic environment for Anammox.The experiment proposed in this article demonstrated that the addition of COD had promoting effect on the denitrification efficiency of the Anammox reactor,but the increase in heterotrophic bacteria brought by it could reduce the relative abundance of anaerobic ammonia oxidizing bacteria.