title: The role of zero valent iron on the fate of tetracycline resistance genes and class 1 integrons during thermophilic anaerobic co-digestion of waste sludge and kitchen waste.
abstract: Activated sludge has been identified as a potential significant source of antibiotic resistance genes (ARGs) to the environment. Anaerobic digestion is extensively used for sludge stabilization and resource recovery, and represents a crucial process for controlling the dissemination of ARGs prior to land application of digested sludge. The objective of this study is to investigate the effect of zero valent iron (Fe0) on the attenuation of seven representative tetracycline resistance genes (tet, tet(A), tet(C), tet(G), tet(M), tet(O), tet(W), and tet(X)), and the integrase gene intI1 during thermophilic anaerobic co-digestion of waste sludge and kitchen waste. Significant decrease (P < 0.05) in the quantities of tet (except tet(W)) and intI1 genes was observed at Fe0dosage of 5 g/L, whereas no significant differences (P > 0.05) were found for all gene targets between digesters with Fe0dosages of 5 and 60 g/L. A first-order kinetic model favorably described the trends in concentrations of tet and intI1 gene targets during thermophilic anaerobic digestion with or without Fe0. Notably, tet genes encoding different resistance mechanisms behaved distinctly in anaerobic digesters, although addition of Fe0could enhance their reduction. The overall results of this research suggest that thermophilic anaerobic digestion with Fe0can be a potential alternative technology for the attenuation of tet and intI1 genes in waste sludge.
authors.affiliation: College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China. Electronic address: pingao@dhu.edu.cn.
authors.forename: Pin
authors.initials: P
authors.lastname: Gao
authors.affiliation: College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China.
authors.forename: Chaochao
authors.initials: C
authors.lastname: Gu
authors.affiliation: College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Wei
authors.affiliation: College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.affiliation: Laboratory of Environmental Sciences and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011, China.
authors.forename: Hanzhong
authors.initials: H
authors.lastname: Jia
authors.affiliation: College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China.
authors.forename: Zhenhong
authors.initials: Z
authors.lastname: Liu
authors.affiliation: College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Xue
authors.affiliation: College of Environmental Science and Engineering, State Environmental Protection Engineering Center for Pollution Treatment and Control in Textile Industry, Donghua University, Shanghai 201620, China. Electronic address: machunyan@dhu.edu.cn.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Ma
mesh_terms: D000693:Anaerobiosis; D019149:Bioreactors; D032023:Integrons / Q000235:genetics*; D007501:Iron; D012722:Sewage; D013752:Tetracycline; D013753:Tetracycline Resistance; D014865:Waste Disposal, Fluid
chemical_list: D012722:Sewage; D007501:Iron; D013752:Tetracycline
keywords: Antibiotic resistance gene; Integrase gene intI1; Kitchen waste; Thermophilic anaerobic co-digestion; Waste sludge; Zero valent iron