Enhancement of extracellular Cr(Ⅵ) reduction for anammox recovery using hydrazine: performance, pathways, and mechanism  

作　　者：Caiyan Qu Lushan Li Fan Feng Kainian Jiang Xing Wu Muchuan Qin Jia Tang Xi Tang Ruiyang Xiao Di Wu Chongjian Tang 

机构地区：[1]School of Metallurgy and Environment,Central South University,Changsha 410083,China [2]Chinese National Engineering Research Center for Control&Treatment of Heavy Metal Pollution,Changsha 410083,China [3]Yongzhou Environmental Monitoring Station,Yongzhou 425000,China [4]Ghent University Global Campus,Incheon,Republic of Korea,Department of Green Chemistry and Technology,Ghent University,and Centre for Advanced Process Technology for Urban Resource Recovery(CAPTURE),Ghent 9000,Belgium

出　　处：《Frontiers of Environmental Science & Engineering》2023年第9期233-243,共11页环境科学与工程前沿（英文）

基　　金：supported by the National Natural Science Foundations of China(No.52000182,U21A20294,51878662);the Natural Science Foundation of Hunan Province(No.2020JJ4725);the Technological Innovation Guidance Program of Jiangxi Province(No.20203BDH80W017).

摘　　要：The hexavalent chromium(Cr(Ⅵ))would frequently impose inhibition to anaerobic ammonium oxidation(anammox)process,hindering the efficiency of nitrogen removal in wastewater treatment.Hydrazine(N2H4),which is an intermediate product of anammox,participates in intracellular metabolism and extracellular Cr(Ⅵ)reduction.However,the roles of N_(2)H_(4)-induced intracellular metabolism and extracellular reduction in nitrogen removal under Cr(Ⅵ)stress remain unclear.The addition of 3.67 mg/L of N2H4 increased the anammox activity by 17%.As an intermediate,N2H4 enhanced anammox metabolism by increasing the heme c content and electron transfer system activity.As a reductant,N_(2)H_(4) accelerated the reduction of c-Cyts-mediated extracellular Cr(Ⅵ)to the less toxic Cr(Ⅲ).Extracellular Cr(Ⅲ)accounts for 74%of the total Cr in a Cr(Ⅵ)-stressed anammox consortia.These findings highlight that N_(2)H_(4)-induced extracellular Cr(Ⅵ)reduction is the dominant mechanism for the survival of anammox consortia.We also found that N_(2)H_(4) increased the production of extracellular polymeric substances to sequester excessive Cr(Ⅵ)and produced Cr(Ⅲ).Taken together,the study findings suggest a potential strategy for enhancing nitrogen removal from ammonium-rich wastewater contaminated with Cr(Ⅵ).

关 键 词：Extracellular Cr(VI)reduction Electron transfer ANAMMOX HYDRAZINE Cr(VI)inhibition 

分 类 号：X70[环境科学与工程—环境工程]