化工学报 ›› 2021, Vol. 72 ›› Issue (10): 5372-5383.DOI: 10.11949/0438-1157.20210310

• 能源和环境工程 • 上一篇    下一篇

零价铁强化生物硝化效能及机理研究

陈红1(),谢静1,成钰莹1,于鑫1,陈善平2,薛罡1(),王美琳1,罗意1,贺向宇1   

  1. 1.东华大学环境科学与工程学院,上海 201620
    2.上海环境卫生工程设计院有限公司,上海 200232
  • 收稿日期:2021-03-03 修回日期:2021-06-29 出版日期:2021-10-05 发布日期:2021-10-05
  • 通讯作者: 薛罡
  • 作者简介:陈红(1986—),女,博士,副教授,chenhong@dhu.edu.cn
  • 基金资助:
    国家自然科学基金项目(51878136);上海市科学技术委员会启明星计划(19QC1400300);中央高校基本科研业务费专项资金;东华大学“励志计划”

Study on performance and mechanism of enhanced biological nitrification by zero-valent iron

Hong CHEN1(),Jing XIE1,Yuying CHENG1,Xin YU1,Shanping CHEN2,Gang XUE1(),Meilin WANG1,Yi LUO1,Xiangyu HE1   

  1. 1.College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China
    2.Shanghai Environmental Sanitation Engineering Design Institute Co. , Ltd. , Shanghai 200232, China
  • Received:2021-03-03 Revised:2021-06-29 Online:2021-10-05 Published:2021-10-05
  • Contact: Gang XUE

摘要:

三氯生(TCS)、纳米铜(CuNPs)等新型污染物进入污水处理系统后会抑制生物硝化效果,且对污泥微生物的长期暴露可能引发抗性基因的富集与传播风险,本研究通过添加零价铁改善受污染物抑制的生物硝化作用。在TCS、CuNPs的单独及联合暴露下,通过测定出水氨氮浓度探究零价铁对污泥硝化的强化作用,通过测定污染物浓度、硝化酶活力、硝化功能基因丰度及微生物种群结构探究零价铁强化生物硝化效能的机理;此外,探究了零价铁对TCS抗性基因(mexB)及铜抗性基因(copA)富集规律的影响。在硝化作用受到TCS、CuNPs抑制时,零价铁的引入可一定程度提高(0.5%~6.7%)一个反应周期内氨氮的去除效率,且长期运行中零价铁有利于硝化效率的提高与恢复。机理研究表明零价铁可降低系统中Cu2+和TCS的浓度,从而减轻污染物的毒性,此外,零价铁可提高两种硝化酶——AMO酶和NXR酶的活性,增加amoA酶功能基因的丰度,促进NitrospiraLacibacter的增长,因此强化了污泥的硝化性能。值得注意的是,TCS和CuNPs的暴露会引起mexB基因及copA基因的富集,而零价铁亦会增加mexB、copA基因的丰度,提高抗性基因的传播风险。

关键词: 三氯生, 纳米铜, 硝化, 抗性基因, 微生物群落, 酶, 曝气, 污染

Abstract:

Emerging contaminants such as triclosan (TCS) and nano-copper (CuNPs) will enter the sewage treatment system and inhibit the biological nitrification performance, and long-term exposure to sludge microorganisms might cause the risk of enrichment and spread of antibiotic resistance genes. The nitrification inhibited by contaminants is improved by adding zero-valent iron in this study. Under the single and combined exposure of TCS and CuNPs, the enhanced effect of zero-valent iron on sludge nitrification was explored by measuring the concentration of ammonia nitrogen in the effluent, and the mechanism of enhanced biological nitrification efficiency by zero-valent iron was investigated by measuring pollutant concentration, nitrification enzyme activity, nitrification functional gene abundance and microbial population structure. Additionally, the influence of zero-valent iron on the fate of TCS resistance gene (mexB) and copper resistance gene (copA) was studied. When nitrification was inhibited by TCS and CuNPs, the introduction of zero-valent iron could increase (0.5%—6.7%) the removal efficiency of ammonia nitrogen in one reaction cycle to a certain extent, and the zero-valent iron was beneficial to the improvement and recovery of nitrification efficiency during long-term operation. Mechanism studies have shown that zero-valent iron could reduce the concentration of Cu2+ and TCS in the system, thereby reducing the toxicity of pollutants. In addition, zero-valent iron could increase the activity of two nitrification enzymes—AMO enzyme and NXR enzyme, and increased the abundance of amoA enzyme functional genes, besides, the abundance of Nitrospira and Lacibacter bacteria was increased by the addition of zero-valent iron, thus enhancing the nitrification performance of the sludge. It was worth noting that exposure of TCS and CuNPs would cause the enrichment of mexB and copA genes, meanwhile zero-valent iron would increase the abundance of mexB, copA genes as well, and increase the risk of transmission of resistance genes.

Key words: triclosan, copper nanoparticles, nitrification, antibiotic resistance genes, microbial community, enzyme, aeration, pollution

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