不同Fe(III)对活性污泥异化铁还原耦合脱氮的影响及机理初探

不同 Fe(III)对活性污泥异化铁还原耦合脱氮的影响及机理初探
王亚娥﹡，冯娟娟，李杰，翟思媛
（兰州交通大学环境与市政工程学院，甘肃 兰州 730070） 摘 要：以投放海绵铁-AT-PVF 复合填料的 SBBR 反应器活性污泥作为铁还原菌菌种来源，采用厌氧恒温培养试验，考察了不同 Fe(III)对活性污
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泥异化铁还原能力及脱氮效果的影响，并对其作用机制进行了初步分析。结果表明：初始基质无 NO2 的前提下，各体系 Fe(III)还原能力与脱氮效 果表现出较好的相关性，同时发生 NO2 -N 和 NO3 -N 的积累现象。其中氧化铁皮体系脱氮效果最好，对 NH4+-N、TN 的累计去除量分别为 75.04 和 80.99mg/L，容积 TN 去除率为 3.88mg N/(L·d)。更进一步的研究发现，不同培养时间内 NH4+氧化量与 Fe(II)产生量具有较好的线性关系，校 正 R2 系数为 0.9249。结合标准吉布斯自由能变化，厌氧环境下 IRB 参与活性污泥中 N 素循环的交互作用机制可分为三个子过程，即 Fe(III)的微生 物还原解离耦合 NH4+的氧化过程、厌氧氨氧化过程和 NO3 -依赖型 Fe(II)氧化过程。其中以 IRB 为主的微生物氧化还原过程对活性污泥中 N 循环 起到了至关重要的作用。 关键词：异化铁还原；活性污泥；铁氨氧化；脱氮；机制 文章编号： 中图分类号：X703.1 文献标识码：A
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Effect and mechanism of nitrogen removal by dssimilatory reduction of different Fe(III) in activated sludge
WANG Ya’e , FENG Juanjuan, LI Jie, ZHAI Siyuan
(School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, Gansu, China) Abstract: An activated sludge from SBBR reactor filled with sponge iron-AT-PVF as filler had been acclimated to Fe(III)-rich environment aiming at secure an enrichment culture of iron-reducing bacteria. The dissimilatory Fe(III) reduction ability and efficiency of nitrogen removal by dosing different Fe(III) under anaerobic condition were investigated. And the mechanism was also discussed. The results showed there is great consistency between ability of Fe(III) reduction and effects of nitrogen removal with no initial NO2 , and NO2 -N and NO3 -N accumulation phenomenon was discovered simultaneously. The results showed there was great consistency between ability of Fe(III) reduction and effect of nitrogen removal, yet the system of oxide iron scale showed better. The accumulated NH4+-N and TN removal amounts were reached up to 75.04 mg/L and 80.99mg/L, respectively. And the maximum nitrogen removal rate was 3.88mg N/(L· Furthermore, the oxidized d). NH4+ and reduced Fe(II) had the line relationship fitted by linear mode, and R-Square was 0.9249.Bonding results and ΔGθ of nitrogen removal using dissimilatory Fe(III) reduction, the whole biodegradation course could divided into three process, Feammox, ANAMMOX and nitrate-dependent Fe(II) oxidation. However, its main role of biodegradation redox process driven by IRB coupled with Fe(III) reduction under anaerobic condition are thermodynamically feasible and is potentially a critical component of N cycle in activated sludge. Key words: Dssimilatory Fe(III) reduction; activated sludge; nitrogen removal; Feammox; mechanism
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引言(Introduction)
异化铁还原，又称铁呼吸，是由特定微生物驱动 的酶促反应，铁还原菌则是实现这一过程的主体。早 在 20 世 纪 就 发 现 了 Fe(III) 还 原 现 象 (Lovely, et al.,1988)，近年来，随着人们对异化 Fe(III)还原过程认
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基金项目：国家自然科学基金项目(No.51068015) Supported by the National Natural Science Foundation of China (No.51068015) 收稿日期： 修订日期： 作者简介：王亚娥（1964—）女，教授，E-mail: wye@; *通讯作者（责任作者） Biography: Wang Ya’e(1964—), female, E-mail: wye@; *Corresponding author
识的不断深入，Fe(III) 的微生物异化还原过程在环境 污染治理与修复领域的应用也越来越得到重视。研究 表明，微生物异化 Fe(III)还原过程可耦联有机物尤其 是难降解有机物（如氯代有机物、偶氮染料、石化类 有机物）的氧化降解、有毒重金属离子（铀，铬，砷 等）的矿化及参与自然界中的氮磷循环(Li F.B. , et al.,2010; Sabrina, et al.,2007)，同时，异化 Fe(III)还原 微生物即铁还原菌（Iron-reducing bacteria, IRB）也是 活性污泥的重要组成部分，该类微生物可占到活性污 泥微生物总量的 3%左右(Jeppe, et al.,2002)。因此，强 化污水处理系统中微生物异化 Fe(III)还原过程，对于