Enhancing nitrogen removal in constructed wetlands: The role of influent substrate concentrations in integrated vertical-flow systems

作     者：Tongtong Liu Da Li Yan Tian Jiajie Zhou Ye Qiu Dongyi Li Guohong Liu Yujie Feng 

作者机构：State Key Laboratory of Urban Water Resource and EnvironmentSchool of EnvironmentHarbin Institute of TechnologyNo.73 Huanghe RoadNangang DistrictHarbin 150090China Institute of Chemical Engineering in Heilongjiang Province3#Nanhu loadHigh Tech R&D Zone of Harbin CityHarbin 150028China 

出 版 物：《Environmental Science and Ecotechnology》 (环境科学与生态技术（英文）)

年 卷 期：2024年第21卷第5期

页      面：103-112页

核心收录：

学科分类：083002[工学-环境工程] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 

基　　金：supported by the National Natural Science Foundation of China(21972036) the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Technology)(No.2022TS07,No.2022ES202210 and No.2022QG202226) support from the National Natural Science Foundation of China(52300199) the Fundamental Research Funds for the Central Universities(FRFCU5710010522) 

主　　题：Constructed wetland Nitrogen removal pathway Denitrification Microbial nitrogen assimilation Enhanced strategy 

摘      要：Recent advancements in constructed wetlands(CWs)have highlighted the imperative of enhancing nitrogen(N)removal ***,the variability in influent substrate concentrations presents a challenge in optimizing N removal strategies due to its impact on removal efficiency and *** we show the interplay between influent substrate concentration and N removal processes within integrated vertical-flow constructed wetlands(IVFCWs),using wastewaters enriched with NO_(3)^(-)-N and NH4þ-N at varying carbon to nitrogen(C/N)ratios(1,3,and 6).In the NO_(3)^(-)-N enriched systems,a positive correlation was observed between the C/N ratio and total nitrogen(TN)removal efficiency,which markedly increased from 13.46±2.23%to 87.00±2.37%as the C/N ratio escalated from 1 to ***,in NH4þ-N enriched systems,TN removal efficiencies in the A-6 setup(33.69±4.83%)were marginally 1.25 to 1.29 times higher than those in A-3 and A-1 systems,attributed to constraints in dissolved oxygen(DO)levels and *** community analysis and metabolic pathway assessment revealed that anaerobic denitrification,microbial N assimilation,and dissimilatory nitrate reduction to ammonium(DNRA)predominated in NO_(3)^(-)-N systems with higher C/N ratios(C/N 3).In contrast,aerobic denitrification and microbial N assimilation were the primary pathways in NH4þ-N systems and low C/N NO_(3)^(-)-N systems.A mass balance approach indicated denitrification and microbial N assimilation contributed 4.12-47.12%and 8.51e38.96%in NO_(3)^(-)-N systems,respectively,and 0.55e17.35%and 7.83e33.55%in NH4þ-N systems to TN *** enhance N removal,strategies for NO_(3)-N dominated systems should address carbon source limitations and electron competition between denitrification and DNRA processes,while NH4þ-N dominated systems require optimization of carbon utilization pathways,and ensuring adequate DO and alkalinity supply.