Enhanced Denitrification in Constructed Wetlands with Low Carbon/Nitrogen Ratios:Insights into Reallocation of Carbon Metabolism Based on Electron Utilization  

作　　者：Hong-Tao Shi Xiao-Chi Feng Zi-Jie Xiao Chen-Yi Jiang Wen-Qian Wang Qin-Yao Zeng Bo-Wen Yang Qi-Shi Si Qing-Lian Wu Nan-Qi Ren 

机构地区：[1]State Key Laboratory of Urban Water Resource and Environment,School of Civil and Environmental Engineering,Harbin Institute of Technology(Shenzhen),Shenzhen 518055,China [2]State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology,Harbin 150090,China

出　　处：《Engineering》2025年第2期222-233,共12页工程(英文)

基　　金：supported by the National Natural Science Foundation of China(52321005);the Guangdong Basic and Applied Basic Research Foundation(2023A1515012383 and 2024A1515030138);the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology,2021TS30);the Shenzhen Science and Technology Program(KQTD20190929172630447 and KCXFZ20211020163404007).

摘　　要：Constructed wetlands(CWs) are a promising method to treat effluent from wastewater treatment plants(WWTPs),However,low carbon/nitrogen(C/N) ratios of the influent inhibit denitrification in CWs,resulting in poor nitrogen removal efficiency.Herein,we compared traditional(control),biochar(BC), andβ-cyclodextrin-fu nctionalized biochar(BC@β-CD) CW systems to investigate nitrogen removal from influent with low C/N ratios,and the mechanisms that enhance this process.The highest nitrogen removal rates were observed in the BC@β-CD group,with rates 45.89% and 42.48% higher than those of the control,accompanied by a 70.57% and 85.45% decrease in nitrous oxide release,when the C/N ratio decreased from4 to 2,respectively.Metagenomic and enzymatic analyses indicated that BC@β-CD enhances nitrogen removal by coordinately promoting carbon metabolism and increasing denitrification enzyme activities,without affecting microbial species diversity in CWs.Structural equation modeling confirmed that the foremost advantages of BC@β-CD were effective electron generation and transportation resulting from increased activities of nicotinamide adenine dinucleotide(NADH) dehydrogenase and the electron transfer system(ETS),thereby strategically reallocating more carbon metabolic flow to support denitrification.Our results show that the application of BC@β-CD in CWs to optimize the reallocation of electrons from carbon metabolism is a feasible strategy to enhance denitrification under low C/N conditions.

关 键 词：Constructed wetland b-Cyclodextrin Biochar Nitrogen removal Carbon metabolism Electron transfer efficiency 

分 类 号：X703[环境科学与工程—环境工程]