School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China.
School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China.
Environ Res. 2023 Jun 1;226:115666. doi: 10.1016/j.envres.2023.115666. Epub 2023 Mar 10.
Ttetracycline (TC) posed potential threats to human health and ecological environment due to its mutagenicity, deformity and strong toxicity. However, few researches focused on the mechanism and their contribution of TC removal through microorganisms combined with zero-valent iron (ZVI) in wastewater treatment field. In this study, three groups of anaerobic reactors, added with ZVI, activated sludge (AS), ZVI coupled with activated sludge (ZVI + AS), respectively, were performed to explore the mechanism and the contribution of ZVI combined with microorganisms on TC removal. The results showed that the additive effects of ZVI and microorganisms improved TC removal. In ZVI + AS reactor, TC was mainly removed by the ZVI adsorption, chemical reduction and microbial adsorption. At the initial period of the reaction, microorganisms played a major role in the ZVI + AS reactors, contributing 80%. The fraction of ZVI adsorption and chemical reduction were 15.5% and 4.5%, respectively. Afterwards, the microbial adsorption gradually reached saturation and the chemical reduction as well as the adsorption of ZVI did their stuff. However, iron-encrustation covered on the adsorption sites of microorganisms and the inhibitory effect of TC on biological activity led to the decreasing TC removal in the ZVI + AS reactor after 23 h 10 min. The optimum reaction time for TC removal in ZVI coupling microbial system was about 70 min. In 1 h 10 min, the TC removal efficiencies were 15%, 63% and 75% in ZVI, AS and ZVI + AS reactors, respectively. Finally, in order to relieve the influence of TC on activated sludge and the iron cladding, a two-stage process was proposed to be explored later in the future.
四环素（TC）由于其致突变性、致畸性和强毒性，对人类健康和生态环境构成潜在威胁。然而，在废水处理领域，很少有研究关注微生物与零价铁（ZVI）结合去除 TC 的机制及其贡献。本研究分别采用添加 ZVI、活性污泥（AS）、ZVI 耦合活性污泥（ZVI+AS）的三组厌氧反应器，探讨 ZVI 与微生物协同去除 TC 的机制及其贡献。结果表明，ZVI 和微生物的协同作用提高了 TC 的去除率。在 ZVI+AS 反应器中，TC 主要通过 ZVI 吸附、化学还原和微生物吸附去除。在反应初期，微生物在 ZVI+AS 反应器中起主要作用，贡献 80%。ZVI 吸附和化学还原的分数分别为 15.5%和 4.5%。随后，微生物吸附逐渐达到饱和，化学还原和 ZVI 的吸附作用发挥作用。然而，铁包被覆盖在微生物的吸附位点上，以及 TC 对生物活性的抑制作用，导致在 23 小时 10 分钟后 ZVI+AS 反应器中 TC 的去除率下降。ZVI 耦合微生物体系中去除 TC 的最佳反应时间约为 70 分钟。在 1 小时 10 分钟时，ZVI、AS 和 ZVI+AS 反应器中 TC 的去除效率分别为 15%、63%和 75%。最后，为了缓解 TC 对活性污泥和铁包被的影响，提出了一种两阶段工艺，以便在未来进一步探索。
