Biological nitrogen removal process could be affected due to the presence of heavy metals owing to their toxicity and accumulation in the sludge.In this study,the impact of Cu2+shock on a long-term nitritation operati...Biological nitrogen removal process could be affected due to the presence of heavy metals owing to their toxicity and accumulation in the sludge.In this study,the impact of Cu2+shock on a long-term nitritation operation was investigated in an air-lift reactor with selfrecirculation.Both the dynamics of microbial community and inhibition kinetics under Cu2+stress were ascertained.The results showed that Cu2+exerted severe inhibition on nitritation performance of an air-lift reactor(ALR)at 25 mg/L.The corresponding NH4+-N removal efficiency decreased to below 50%,which was mainly due to the variation of microbial community structure,especially the inhibition of nitrifiers like Nitrosomonas(the relative abundance decreased from 30%to 1%after Cu2+inhibition).Kinetic parameters were obtained and compared after fitting the Haldane model.The long-term Cu2+stress on the ALR aggravated the ammonium affinity and the resistance to substrate self-inhibition of the nitritation sludge,but reduced the resistance to Cu2+inhibition.Furthermore,Cu2+acted as uncompetitive inhibitor on nitritation process.Our results provide new insights into the nitritation characteristics under long-term Cu2+stress.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51878662,51674305)the Key Project of Science and Technology Program of Hunan Province(No.2017SK2420)+1 种基金the Fundamental Research Funds for the CentralUniversities of Central South University(No.2017zzts599)supported by the 2017 Huxiang Provincial Scholar Program and the 2018 Distinguished Youth Program of the Natural Science Foundation of Hunan Province(No.2019JJ20033)
文摘Biological nitrogen removal process could be affected due to the presence of heavy metals owing to their toxicity and accumulation in the sludge.In this study,the impact of Cu2+shock on a long-term nitritation operation was investigated in an air-lift reactor with selfrecirculation.Both the dynamics of microbial community and inhibition kinetics under Cu2+stress were ascertained.The results showed that Cu2+exerted severe inhibition on nitritation performance of an air-lift reactor(ALR)at 25 mg/L.The corresponding NH4+-N removal efficiency decreased to below 50%,which was mainly due to the variation of microbial community structure,especially the inhibition of nitrifiers like Nitrosomonas(the relative abundance decreased from 30%to 1%after Cu2+inhibition).Kinetic parameters were obtained and compared after fitting the Haldane model.The long-term Cu2+stress on the ALR aggravated the ammonium affinity and the resistance to substrate self-inhibition of the nitritation sludge,but reduced the resistance to Cu2+inhibition.Furthermore,Cu2+acted as uncompetitive inhibitor on nitritation process.Our results provide new insights into the nitritation characteristics under long-term Cu2+stress.
