Hematite-facilitated microbial ammoxidation for enhanced nitrogen removal in constructed wetlands  

作　　者：Hao Qin Wenbo Nie Duo Yi Dongxu Yang Mengli Chen Tao Liu Yi Chen 

机构地区：[1]Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment(Ministry of Education),Chongqing University,Chongqing 400045,China [2]College of Environment and Ecology,Chongqing University,Chongqing 400045,China [3]Faculty of Geosciences and Environmental Engineering,Southwest Jiaotong University,Chengdu 610031,China

出　　处：《Frontiers of Environmental Science & Engineering》2024年第7期35-45,共11页环境科学与工程前沿（英文）

基　　金：This work was funded by the National Natural Science Foundation of China(No.52170150);Chongqing Science Fund for Distinguished Young Scholars(China)(No.CSTB2022NSCQ-JQX0023);Fundamental Research Funds for the Central Universities(China)(No.2020CDJDPT002).

摘　　要：Constructed wetlands(CWs)are widely applied for decentralized wastewater treatment.However,achieving efficient removal of ammonia(NH+-N)has proven challenging due to insufficient oxygen.In this study,natural hematite(Fe,O3)was employed as a CW substrate(H-CWs)for the first time to drive anaerobic ammonia oxidation coupled with iron(I)reduction(Feammox).Compared to gravel constructed wetlands(G-CWs),ammonia removal was enhanced by 38.14%to 54.03%and nitrous oxide(N_(2)0)emissions were reduced by 34.60%in H-CWs.The synergistic removal of ammonia and nitrate by H-CWs also resulted in the absence of ammoxidation by-products.Inhibitor and 15N isotope tracer incubations showed that Feammox accounting for approximately 40%of all ammonia removal in the H-CWs.The enrichment of iron phosphate(Fe_(3)Fe_(4)(PO_(4))_(6))promoted the accumulation of the Feammox intermediate compound FeOOH.Microbial nanowires were observed on the surface of H-CW substrates as well,suggesting that the observed biological ammoxidation was most likely related to extracellular electron transfer(EET).Microbial and metagenomics analysis revealed that H-CWs elevated the integrity and enhanced the abundance of functional microorganisms and genes associated with nitrogen metabolism.Overall,the efficient ammonia removal in the absence of O2 together with a reduction in N_(2)O emissions as described in this study may provide useful guidance for hematite-mediated anaerobic ammonia removal in CWs.

关 键 词：Constructed wetlands Nitrogen removal Feammox HEMATITE Iron cycle 

分 类 号：X703[环境科学与工程—环境工程] TM911.45[电气工程—电力电子与电力传动]