镉离子对养殖废水生物脱氮性能及功能基因的影响

Effects of Cd^(2+)on Biological Nitrogen Removal Performance and Functional Genes of Livestock Wastewater

选取了养殖废水中的重金属污染物镉离子为研究对象,为揭示其对生物脱氮系统的影响。检测氮转化功能基因丰度,确定功能基因与理化参数相关性并分析镉离子胁迫下生物脱氮的驱动因素。实验结果表明,镉离子显著抑制生物脱氮性能,硝化过程对于镉离子的敏感性相比于氨氧化过程更强。细菌16S rRNA和氮转化功能基因的丰度随镉离子浓度的升高而显著降低,其中出水氨氮、好氧末端硝酸盐氮浓度都与功能基因呈较强的相关性。此外,硝化和氨氧化水平、NO_(2)^(-)-N的氧化能力、完全反硝化水平是生物脱氮性能的关键驱动因素,分别对氨氮去除率、亚硝酸盐氮积累率、反硝化阶段硝酸盐氮去除率有显著影响。本研究从分子生物学角度揭示镉离子对于生物脱氮的影响,为金属离子对于生物脱氮系统的影响研究提供了理论依据。

This paper selected Cd^(2+)in livestock wastewater to reveal its influence on the biological nitrogen removal systems.The abundance of nitrogen transformation functional genes were detected to determine the correlation between functional genes and physicochemical indexes and analyze the driving factors of biological nitrogen removal under Cd^(2+)stress.The results showed that Cd^(2+)significantly inhibited the performance of biological nitrogen removal,and the nitrification process was more sensitive to Cd^(2+)than the ammonia oxidation process.The abundance of 16S rRNA and functional genes significantly decreased with the increase of Cd^(2+)concentration,and the concentrations of effluent ammonia and aerobic terminal nitrate were strongly correlated with the abundance of functional genes.In addition,nitrification and ammonia oxidation levels,oxidation capacity of NO_(2)^(-)-N,and complete denitrification level are the key driving factors of biological nitrogen removal performance.They have significant effects on the removal rate of ammonia,nitrite accumulation rate,and nitrate removal rate in the denitrification stage.This study reveals the effects of Cd^(2+)on biological nitrogen removal from the perspective of molecular biology and provides a theoretical basis for the study of the effects of metal on biological nitrogen removal systems.