城市污水处理厂二级出水中硝酸盐与有机微污染物(OMPs)常常共存,OMPs对反硝化深度脱氮过程的影响尚不明确。为解析OMPs作用下反硝化脱氮过程响应规律,搭建了反硝化移动床生物膜反应器,并针对OMPs作用下的反硝化性能、OMPs去除效果、微生物胞外聚合物(EPS)响应和电子传递链关键酶活性等方面开展了研究。结果表明:OMPs明显降低反硝化脱氮性能,导致碳、氮去除率均出现波动,且降至70%以下;OMPs中炔雌醇(EE)、雌三醇(E3)、双氯芬酸(DCF)的去除率均在75%以上,而卡马西平(CBZ)去除率维持在20%~44%。在OMPs作用下,微生物首先利用部分EPS作为代谢的有机碳源,随后分泌更多EPS以抵御OMPs的胁迫。同时,电子传递链的关键酶活性受到抑制,使电子传递的有效性降低,进而导致反硝化性能变差。值得关注的是,高浓度的OMPs对系统反硝化效果、EPS含量、电子传递链关键酶活性的冲击更强烈,但微生物的代谢响应比低浓度组更快。该研究为尾水深度脱氮与OMPs的协同去除提供参考。

In conventional urban sewage treatment plants, nitrate nitrogen and a wide range of organicmicropollutants (OMPs), including endocrine disruptors and pharmaceuticals, frequently coexist in theeffluent  from  secondary  treatment  processes.  These  compounds  have  been  demonstrated  to  exertsignificant effects on various microorganisms. However, their influence on the advanced denitrificationprocess remains to be comprehensively elucidated. This study aimed to investigate the response of thedenitrification process to OMPs through the construction and operation of three denitrification movingbed biofilm reactors. The reactors were employed to evaluate the denitrification removal rate, assess theefficiency of micropollutant removal, analyze the response of extracellular polymeric substances (EPS)Energy Environmental Protectionin the biofilm, and examine variations in key enzyme activities within the electron transport chain. Thefindings  revealed  that  the  presence  of  OMPs  had  a  detrimental  impact  on  denitrification  efficiency,resulting in instability and a significant reduction in carbon and nitrogen removal rates to below 70%.Concurrently, the removal efficiencies of micropollutants such as ethinyl estradiol (EE), estriol (E3),and diclofenac (DCF) were found to exceed 75%, whereas the removal rates of carbamazepine (CBZ)varied  between  20%  and  44%.  This  suggests  that  different  OMPs  are  handled  differently  by  thedenitrification system. During the introduction of micropollutants into the systems, it was observed thatmicroorganisms initially utilized a portion of the EPS as a nutrient source, indicating an important roleof  EPS  in  microbial  adaptation.  Subsequently,  in  response  to  the  stress  induced  by  OMPs,  thesemicroorganisms secreted additional EPS. This response underscores that EPS plays a crucial role in themicrobial adaptation to micropollutant stress. Moreover, the activity of key enzymes within the electrontransport chain was inhibited due to the presence of micropollutants, thus reducing electron transportefficiency  and  consequently  impairing  the  overall  denitrification  performance.  The  study  furtherdemonstrated  that  elevated  concentrations  of  organic  micropollutants  exerted  a  more  pronouncednegative impact on denitrification efficiency, EPS content, and key enzyme activities within the electrontransport chain, leading to an accelerated metabolic response from microorganisms. This study providesvaluable insights into the complex interactions between micropollutants and denitrification processes,particularly  regarding  the  effect  of  OMPs  on  denitrification.  It  highlights  an  urgent  need  forenhanced strategies aimed at improving nitrogen removal alongside co-removal of these contaminantsduring wastewater treatment. Understanding these impacts is essential for developing more effectivetreatment technologies to address challenges posed by both nitrate and OMPs present in wastewatereffluents.