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膜曝气生物膜反应器污水处理过程N2O排放特性及减排策略

王亚宜, 贺泰来, 李佳, 吴巧玉, 汪涵, 赵立功

王亚宜, 贺泰来, 李佳, 吴巧玉, 汪涵, 赵立功. 膜曝气生物膜反应器污水处理过程N2O排放特性及减排策略[J]. 北京工业大学学报, 2025, 51(3): 350-358. DOI: 10.11936/bjutxb2024070004
引用本文: 王亚宜, 贺泰来, 李佳, 吴巧玉, 汪涵, 赵立功. 膜曝气生物膜反应器污水处理过程N2O排放特性及减排策略[J]. 北京工业大学学报, 2025, 51(3): 350-358. DOI: 10.11936/bjutxb2024070004
WANG Yayi, HE Tailai, LI Jia, WU Qiaoyu, WANG Han, ZHAO Ligong. N2O Emission Characteristics and Mitigation Strategies in Membrane Aerated Biofilm Reactors for Wastewater Treatment[J]. Journal of Beijing University of Technology, 2025, 51(3): 350-358. DOI: 10.11936/bjutxb2024070004
Citation: WANG Yayi, HE Tailai, LI Jia, WU Qiaoyu, WANG Han, ZHAO Ligong. N2O Emission Characteristics and Mitigation Strategies in Membrane Aerated Biofilm Reactors for Wastewater Treatment[J]. Journal of Beijing University of Technology, 2025, 51(3): 350-358. DOI: 10.11936/bjutxb2024070004

膜曝气生物膜反应器污水处理过程N2O排放特性及减排策略

基金项目: 

国家杰出青年科学基金资助项目 52225001

详细信息
    作者简介:

    王亚宜(1971—),女,教授,主要从事水污染控制和微生物技术方面的研究,E-mail: wyywater@126.com

  • 中图分类号: U461;TP308

N2O Emission Characteristics and Mitigation Strategies in Membrane Aerated Biofilm Reactors for Wastewater Treatment

  • 摘要:

    膜曝气生物膜反应器(membrane aerated biofilm reactor,MABR)作为一种新型的污水处理技术,因其高效的氮去除能力和较低的N2O排放水平而受到广泛关注。传统污水处理脱氮过程中,硝化反硝化阶段主要通过羟胺氧化、AOB反硝化、异养反硝化以及化学变化途径产生N2O。MABR处理市政污水较传统曝气方式具有更低的N2O排放潜力,主要得益于MABR特殊的底物异向扩散模式和无泡曝气方式,这会减少N2O产生潜力及排放水平。该文总结了MABR在运行过程中N2O产生与降低途径,讨论了N2O产生和排放的影响因素及控制策略,并对今后研究MABR体系中N2O排放进行了展望,以期说明MABR进一步工程应用在碳减排方面的优势。

    Abstract:

    The membrane aerated biofilm reactor (MABR), as a novel wastewater treatment technology, has garnered extensive attention for its high nitrogen removal performance and reduced nitrous oxide (N2O) emissions. In the context of conventional biological nitrogen removal process, N2O is produced through four main pathways, including hydroxylamine oxidation, AOB denitrification, heterotrophic denitrification, and chemical reactions. Remarkably, the MABR exhibits a lower potential for N2O emission compared to traditional aeration methods. This decrease is primarily due to its unique substrate counter-diffusion mechanism and bubbleless aeration, which mitigate N2O production potential and emission level. This paper summarizes the pathways of N2O generation and reduction in MABR systems, discusses the influencing factors and control strategies of N2O generation and emission, and looks forward to the future research directions for N2O emission management in MABRs, thereby highlighting the advantages of MABR in further engineering application in carbon emission reduction.

  • 随着城镇化与工业化进程的不断推进,我国生活污水和工业废水产生量逐年增加。与此同时,为了提升水环境质量,缓解水体富营养化问题,污水排放标准日益严格,导致污水处理厂的能量消耗逐步上升。据预测,到2030年污水处理行业碳排放量将占全社会总碳排放量的2.95%[1]。因此,污水处理行业的减污降碳协同增效势在必行,应力求提升能源利用效率,减少碳排放。

    污水处理厂碳排放分为间接碳排和直接碳排。间接碳排包括曝气风机能耗、提升泵能耗等,其中主要用于硝化的曝气能耗占到总能耗的50%~70%;直接碳排有CH4、N2O和CO2等温室气体排放[2]。传统的生物脱氮包括好氧硝化和缺氧反硝化2个阶段,N2O作为脱氮过程的中间产物逐渐引起研究学者和各国政府的关注。N2O是一种重要的温室气体,其增温潜势是CO2的近300倍,并且会对臭氧层产生破坏[3-9]。2010年,污水处理过程排放的N2O总量达20万t,占到总排放量的3%[10]。有学者曾推测2005—2020年,污水处理厂排放的N2O总量增加约13%[8],其影响占污水处理厂总CO2足迹的78.4% [11]。因此,N2O排放已成为评价污水处理厂碳足迹的重要指标[12-13]

    在膜曝气生物膜反应器(membrane aerated biofilm reactor,MABR)中,氧气透过曝气膜传递给微生物,由生物膜内层向外层扩散,污水中的氨氮和有机物从生物膜外层向内层扩散[14-17]。氧气从膜侧向液相浓度递减,氨氮和有机物从液相向膜侧浓度递减,底物相反的扩散方向形成独特的氨氧化菌(ammonia oxidizing bacteria,AOB)、亚硝酸盐氧化菌(nitrite oxidizing bacteria,NOB)和异养菌(heterotrophic bacteria,HB)分层分布方式[18-20]。MABR利用无泡曝气方式使得氧传质效率大幅提高,节省曝气产生的能耗,减少间接碳排;同时,其特殊的扩散模式将在生物膜内部形成电子供体与电子受体共存的生态位[15, 21-25],实现污染物高效去除的同时有利于消耗膜内微生物代谢产生的N2O,进而减少N2O的释放[16],实现直接碳排放降低。目前,已有许多研究发现MABR具有节能降耗、提质增效的潜力,并在减少N2O排放方面具有独特优势。丹麦某污水处理厂安装MABR组件作为升级改造方式,研究发现MABR在寒冷条件下也表现出优秀的硝化能力[26],并且通过监测发现N2O整体释放水平较低[27]。然而,针对MABR运行过程中减少N2O排放的原理和影响因素及控制策略的研究仍较少,也缺乏综述系统总结其排放特性。

    本文介绍了传统生物脱氮及MABR系统中N2O的产生途径,分析了不同影响因素下N2O产量的差异与趋势,提出了可能的N2O排放控制策略,展望了未来污水厂利用MABR作为升级改造方式在碳减排方面的优势,以期为减少污水处理过程中N2O的排放提供理论依据。

    在传统生物脱氮过程中主要存在3种N2O产生途径,分别为羟胺(NH2OH)氧化途径、AOB反硝化途径和异养反硝化途径(见图 1)。

    图  1  污水处理脱氮过程N2O产生方式[28]
    AMO—氨单加氧酶;HAO—羟胺氧化还原酶;cyt P460—c型血红素;Nir—亚硝酸盐还原酶;Nar—硝酸盐还原酶;Nor—NO还原酶;Ntr—异构亚硝酸盐还原酶;Nos—N2O还原酶。
    Figure  1.  N2O production pathways in the wastewater treatment process[28]

    1) 羟胺氧化途径。AOB利用氨单加氧酶(AMO)将污水中的氨氮(NH3)氧化为NH2OH,并进一步利用羟胺氧化还原酶(HAO)将NH2OH氧化为亚硝酸盐(NO2-)[8]。NH2OH在无氧条件下会被细胞色素C直接氧化为N2O[29];或先经HAO生成NO,后被异养菌还原为N2O[8]。这种主要由NH2OH引发产生N2O的途径称为NH2OH氧化途径。

    2) AOB反硝化途径。一方面,当系统中出现NO2-积累时,AOB会分泌NO2-还原酶(Nir)和NO还原酶(Nor),将NO2-还原为NO,进一步还原为N2O,而AOB缺少编码N2O还原酶(Nos)的基因,因此无法还原N2O,导致N2O积累[30];另一方面,AOB会分泌异构NO2-还原酶(Ntr)将NO2-直接还原为N2O[31]。这2种生物转化途径在ρ(DO) < 1.5 mg/L时即可发生,ρ(DO) < 0.2 mg/L时更为明显。这一N2O产生途径称为AOB反硝化途径。该途径发生的前提在于系统ρ(DO)较低,NOB的活性受到抑制,造成NO2-积累。

    3) 异养反硝化途径。在缺氧环境下,异养反硝化细菌利用有机物作为电子供体,将NO3-逐步还原为N2,其中Nos有着更高的氮还原速率,因此不会导致N2O积累。然而当缺氧环境被破坏或有机物不足时,Nos活性受到抑制,产生的N2O无法及时转化,将导致N2O积累[32]。另外,有部分细菌在反硝化至N2O过程已获得生长所需能量,如荧光假单胞菌(Pseudomonas fluorescens),因此不具备还原N2O的能力,也将造成N2O积累[33]。这一N2O产生途径称为异养反硝化途径。

    除此以外,在氮素转化过程中,N2O还可以通过化学过程生成。NH2OH与O2反应会产生N2O,该反应在微量金属元素(铜、铁、锰等)存在时更易发生[34],反应方程式为

    $$ \mathrm{NH}_2 \mathrm{OH}+0.5 \mathrm{O}_2=0.5 \mathrm{~N}_2 \mathrm{O}+1.5 $$ (1)

    Soler-Jofra等[35]发现HNO2与NH2OH反应同样会产生N2O,反应方程式为

    $$ \mathrm{NH}_2 \mathrm{OH}+\mathrm{HNO}_2=\mathrm{N}_2 \mathrm{O}+2 \mathrm{H}_2 \mathrm{O} $$ (2)

    完全氨氧化(Comammox)过程的功能细菌本身不含有产生N2O的基因,但Kits等[36]发现,Comammox纯菌培养产生的N2O产量为进水TN负荷的0.05%~0.50%,与胞外仅通过NH2OH进行化学反应产生的N2O接近,证明了化学过程产生N2O在生物系统中也是存在的。大多数通过化学途径产生N2O的过程中,金属离子都起到了催化加速反应的作用,而实际生活污水由化学过程生成的N2O所占比例较低,对整体N2O产生的影响较小。

    经试验验证和模型分析发现,生物脱氮过程中MABR具有降低N2O产生和释放潜力。

    Kinh等[37]通过研究MABR与传统生物膜反应器发现,MABR的表面氮去除率((4.51±0.52)g/(m2·d))高于传统生物膜((3.56±0.81)g/(m2·d)),但N2O和NO释放量显著降低。MABR生物膜-液界面处NO和N2O质量浓度分别为(0.006 6±0.001 4)mg/L和(0.010 0±0.000 9)mg/L(以N计,下同),分别为基于传统曝气法生物膜反应器的50.0%和3.6%。He等[38]通过模型预测得出,在厌氧/缺氧/好氧(A/A/O)系统中嵌入MABR后,系统排放的N2O仅为传统曝气方式活性污泥法的1/5。Peng等[39]通过建模评估了同向扩散生物膜(传统生物膜)和异向扩散生物膜(MABR生物膜)中AOB反硝化途径和NH2OH氧化途径对N2O产生的贡献。研究发现,在高氨氮(500 mg/L)、较厚生物膜深度(300 μm)和中等氧负荷(1~4 m3/d)条件下运行时,同向扩散生物膜N2O产生量(约为45 mg/(L·h))显著高于异向扩散生物膜(约为29 mg/(L·h))。由此可知,MABR在脱氮及N2O排放控制方面有着独特的优势和潜力。

    MABR系统N2O减排机制主要与其特殊的异向扩散生物膜结构相关。由上述N2O产生途径可知,低DO浓度或低有机物浓度均会促进N2O的生成。而MABR生物膜中,底物的异向扩散形成了独特的生物膜分层结构,内层生物膜虽有机物浓度低不利于完全反硝化,但高DO浓度利于NH3或NH2OH氧化完全;同理外层生物膜DO浓度低,但有机物浓度高,利于完全反硝化。可见MABR生物膜中易于产生N2O的不利区域范围较小,进而减缓整体N2O的产生及释放[4]。MABR生物膜的分层分布为靠近中空纤维膜侧AOB和NOB较多,靠近液相异养菌较多;底物分布为靠近膜侧氧气较多,氧气浓度随着生物膜的深入而降低,靠近液相COD和氨氮浓度较高,由于COD受到生物膜的传质阻力较大,而氨氮阻力较小,因此COD在生物膜-液界面较高,而氨氮可以渗透到膜内侧氧气浓度较高的区域,供硝化细菌利用[40]。基于上述反扩散模式,靠近膜侧的AOB氧化NH3时会产生中间产物NH2OH,NH2OH会通过前文所述方式,经过生物或化学反应生成N2O,即NH2OH氧化途径。膜外侧异养菌分步进行反硝化反应,当电子供应有限时,不完全反硝化导致N2O生成[41],即异养反硝化途径。而对于AOB反硝化途径,由于MABR有着较高的氧传质效率,靠近膜侧生长的AOB会更高效利用氧气进行硝化,反硝化更多由外层异养菌进行。因此,在MABR工艺中AOB反硝化途径对N2O生成的贡献较少,N2O主要由羟胺氧化和异养反硝化途径生成[42]。同时,生成的N2O在向外层生物膜扩散过程中,会逐渐进一步被还原,最终N2O产量降低,如图 2所示。

    图  2  MABR特殊的异相扩散传质[43]
    Figure  2.  Counter-diffusion mass transfer of MABR[43]

    综上,MABR相较于传统的生物脱氮系统减少N2O排放的优势在于:

    1) 氧渗透深度浅。MABR中氧气的渗透深度仅为200 μm左右[44],即使氧气供应不足导致N2O生成,产生的N2O逐步向外层生物膜扩散过程中,液相高COD、低DO的条件也会促进N2O的还原,从而降低N2O产生及释放可能[41]

    2) 碳源利用率高。MABR独特的微生物分层结构以及更高的氧气利用效率使得供给的氧气更多用来氧化NH3,更多碳源可供给异养菌用于反硝化。更高的碳源利用效率也可以减少异养反硝化途径产生的N2O。

    3) 无泡曝气。MABR工艺中,N2O产生于生物膜,一部分N2O扩散进入膜丝内部后随尾气排出[44];一部分N2O进入液相,而MABR无泡曝气的特点使N2O被曝气排出的气态释放量降低[44]

    但MABR在运行过程中,为保证生物膜内微生物的活性,需要对生物膜进行曝气冲刷来控制厚度,这一过程可能会导致生物膜中的N2O进入液相进而曝气排出[41]

    在污水脱氮过程中,水质波动及工艺参数变化都可能影响N2O产生。当进水NH3升高时,原有的曝气量不足以将NH3完全氧化,DO浓度偏低将造成NH2OH和NO2-的积累,并进一步增大N2O转化可能;当进水碳源不足时,也会导致生成的N2O无法及时反硝化而产生更多N2O。有效控制N2O排放是充分发挥MABR污水处理节能降耗优势的重要方面[41]。因此,研究MABR运行过程N2O产生关键因素并进行有效控制至关重要。

    在MABR系统中,N2O释放量主要与供氧量、生物膜厚度、处理工艺、系统中的微生物以及反应器构型与运行方式有关,主要关键因素如表 1所示。

    表  1  MABR产生N2O的影响因素
    Table  1.  Influencing factors of N2O production in MABR
    序号 研究因素及参数 研究方式 参考文献
    1 氧表面负荷(1.821 g/(m2·d)~3.641 g/(m2·d))、水力停留时间(0.3~0.8 d)、进水COD(120~520 mg/L)、生物膜厚度(100~600 μm) 数学建模 [42]
    2 曝气方式(间歇曝气,Int4+4,Int0.25+0.25) 实验室规模研究 [45]
    3 曝气方式(间歇曝气,Int6+6,Int11+1,Int9+3,Int6+2,Int1+1) 实验室规模研究 [46]
    4 生物膜厚度(0~1 000 μm) 数学建模 [47]
    5 ρ(C)/ρ(N)(3.00±0.14,1.67±0.07) 实验室规模研究 [48]
    7 传质方向(纵向传质) 数学建模 [49]
    注:Inton+off表示间歇曝气过程中,on为曝气时间,off为停止曝气或曝入氮气时间,单位为h。
    下载: 导出CSV 
    | 显示表格

    在MABR系统中,N2O排放量整体较低且变化幅度不大,仅产生途径发生了改变。Liu等[42]通过建模研究了氧表面负荷对MABR生物膜内N2O产生的影响,随着氧表面负荷从1.821 g/(m2·d)增至3.641 g/(m2·d),N2O产生量先升高再降低,并在2.913 g/(m2·d)时达到峰值。低氧状态下,NOB活性受到抑制,NO2-大量积累,N2O主要由AOB反硝化途径生成,但此时异养菌活性较高且碳源充足,生成的N2O大部分被异养反硝化过程消耗,使得这一阶段N2O产生量较低。随着氧表面负荷从3.095 g/(m2·d)增至3.641 g/(m2·d),过高的供氧量虽不利于外层异养细菌的完全反硝化,但整体上氨氮氧化较为彻底,AOB产生的NO2-被NOB及时消耗,此时NH2OH氧化途径可能将生成少部分N2O。Li等[50]同样研究发现在高溶解氧条件下,进行同步硝化反硝化的MABR系统中羟胺氧化途径对N2O的生成起着重要作用。当供氧量处于某一中间值时,既会影响异养反硝化又无法彻底氧化氨氮,就会产生较多的N2O。

    目前关于MABR生物膜厚度对N2O产生量的规律研究尚不明确,随着生物膜厚度的增加,N2O产量增加和减少现象均有报道,可能主要与实际运行参数和水质情况有关。Chen等[47]研究发现较厚的生物膜相比于较薄的生物膜产生的N2O更多,主要因为氧气和有机物的扩散受到限制。然而,Liu等[42]通过建模得到,较厚的生物膜会产生较少的N2O,并发现160~280 μm的生物膜是MABR中降低N2O产率的最佳厚度。随着生物膜厚度从100 μm增至600 μm,N2O产量先上升后下降,N2O生产因子的变化趋势与AOB反硝化途径相似,AOB反硝化途径成为主要的N2O生成途径,并且发现羟胺氧化途径对N2O生成没有贡献。Li等[50]发现异养MABR系统中N2O的产生途径主要是NH2OH氧化途径和异养反硝化途径,可能与供氧、HRT和有机物浓度的最佳条件不同有关。此外,通过冲刷作用维持生物膜一定厚度是保证MABR脱氮性能的关键因素,而这会导致外部生物膜脱落,膜内的N2O进入液相,进而后续进入好氧池中被曝气排出。可见,急需继续深入研究生物膜厚度与N2O释放量之间的关系和作用机制,并结合实际运行操作过程,探索出合适的清洗强度和频率,在保持MABR良好的脱氮性能同时实现最大限度减少N2O的排放。

    MABR生物膜系统有着独特的异向扩散结构,生物膜内生长着多种类型的功能微生物,即N2O产生与消耗的微生物都生长在生物膜中。值得关注的是,一部分特定微生物具有还原N2O的能力,会影响MABR系统整体N2O的排放量。例如,Thauera mechernichensis可在高DO浓度条件下将N2O还原为N2[51]Rhizobium同样带有N2O还原酶合成基因[52],并且在MABR外层分布较内层更为广泛[4]Stenotrophomonas nitritireducensBrevundimonas diminuta也被检测出在市政污水处理系统中存在并具有N2O还原能力[53-57]。MABR特殊的生物膜分层结构为上述功能细菌提供了合适的生态位空间分布,形成了MABR特有的N2O控制策略。

    将MABR工艺与Anammox工艺相结合,可进一步减少MABR系统N2O的产生。Anammox是一种自养脱氮工艺,消耗NO2-的同时且不产生N2O。这一结合方式不仅可以减少由于NO2-积累导致的AOB反硝化生成N2O,同时节省更多的碳源用于反硝化完全脱氮,对控制N2O的产生有着独特优势[46]。Ni等[58]通过建模研究了Anammox对MABR脱氮过程中N2O生成的影响,发现提高厌氧氨氧化活性不仅有助于实现高水平的氮去除,还有助于减少NO和N2O的产生。在短程硝化耦合厌氧氨氧化工艺(partial nitrification and Anammox,PN/A)中,MABR可以通过调控DO浓度、曝气压力[26]以及接种亚硝化污泥[59]等方式,实现亚硝化的稳定运行,进一步促进Anammox实现高效脱氮,减少N2O的产生。因此将MABR进一步耦合Anammox等污水处理工艺,并针对不同水质采用不同操作条件,优化MABR系统的设计和运行,可更大程度缓解N2O产生。

    MABR运行时主要有2种曝气方式,分别为贯通式和死端式[60]。贯通式是指MABR膜组件的进气端和出气端均不封闭,在进气口和排气口都有气体的流通,气体流经MABR膜丝后含氧量降低,氧气供给微生物使用,同时微生物代谢产生的废气随气体排出。死端式MABR膜组件的进气端敞开,而排气端封闭,气体从进气口进入MABR膜组件内,全部透过膜丝被微生物所利用。死端式运行时,氧气浓度会沿平行于膜丝的方向逐渐降低,氧传质梯度也不断降低,同时由于反应器运行存在死区,底物浓度存在差异等原因,平行于MABR膜丝的方向会出现底物分布不均匀性,形成的生物膜厚度也不尽相同,最终导致生成不同浓度的N2O。Chen等[49]通过数学建模手段,利用分区块、分隔段的方式,研究了平行于膜丝方向氧气浓度、底物浓度和生物膜厚度对N2O产量的影响,最终得出将膜组件设计为贯通式运行,并且反应器设计为连续搅拌式反应器,可以在保持良好脱氮性能的同时,最大程度减少N2O的产生。

    死端式曝气方式的优点在于氧气的传递效率理论上可以达到100%,为进一步提高氧气利用效率,减少能量损失,有学者提出利用间歇曝气提高氧传递性能[61],即死端式与贯通式交替运行。同时,对MABR与Anammox耦合系统进行间歇曝气可进一步降低N2O排放:间歇曝气可抑制NOB活性,增强了厌氧氨氧化细菌活性,同时建立了一个缺氧的N2O还原区[46];Ma等[46]对比发现,间隔6 h的间歇曝气相较于连续曝气可降低N2O排放量;Ni等[58]研究发现将曝气频率设置为8次/d,N2O产量最低。

    可见,对于不同水质水量条件来选择不同的处理工艺、不同类型的反应器以及曝气方式和曝气频率,对N2O的减排也具有积极作用,但如何来选择合适的污水工艺及相关运行参数急需更多的研究支撑。

    已有许多研究表明MABR具有良好的脱氮性能和节能效果,在污水处理提质增效方面有着独特的优势。同时,N2O作为污水处理厂温室气体排放的重要组分,MABR具有缓解N2O产生的特点。本文对污水处理脱氮过程及MABR生物膜中N2O的产生及排放特性机制原理进行了分析,并综述了已有科研文献,对MABR运行过程中影响N2O排放的关键因素进行了总结,提出不同操作运行条件下不同的N2O释放规律。尽管目前对于MABR中N2O的研究取得了一定进展,但仍存在一些方向供未来研究展望:

    1) 目前针对于MABR运行过程中产生的N2O问题,更多还是以建立数学模型的方式进行模拟预测,也有实验室规模的研究,而基于中试和实际应用的探索较为短缺。在我国碳达峰、碳中和的政策下,应开展更多针对实际污水处理厂的数据追踪,并研究N2O的减排机制。

    2) 我国在N2O采样和监测方面还未制定统一的标准,使得不同的采样和监测策略可能会导致即使在同一个污水处理设施中测得的结果也会出现差异[11, 62-64];同时,由于污水厂进水负荷和MABR曝气方式的影响,N2O的排放在时间和空间维度出现分布差异[65-67]。因此在进行N2O的采样与监测时,最好能形成统一标准,通过长期连续监测,提升数据精准度,减小采样和监测方法不同带来的系统误差。

    3) 已有研究发现MABR系统中CH4的排放相较于传统生物脱氮系统明显增多[38],可能是由于MABR生物膜氧气浓度较低的区域会促进厌氧产甲烷菌的生长,CH4会随着MABR的废气排出或在好氧区曝气排出。因此,MABR系统中温室气体总体排放量或许是未来研究需重点考虑的方向。

  • 图  1   污水处理脱氮过程N2O产生方式[28]

    AMO—氨单加氧酶;HAO—羟胺氧化还原酶;cyt P460—c型血红素;Nir—亚硝酸盐还原酶;Nar—硝酸盐还原酶;Nor—NO还原酶;Ntr—异构亚硝酸盐还原酶;Nos—N2O还原酶。

    Figure  1.   N2O production pathways in the wastewater treatment process[28]

    图  2   MABR特殊的异相扩散传质[43]

    Figure  2.   Counter-diffusion mass transfer of MABR[43]

    表  1   MABR产生N2O的影响因素

    Table  1   Influencing factors of N2O production in MABR

    序号 研究因素及参数 研究方式 参考文献
    1 氧表面负荷(1.821 g/(m2·d)~3.641 g/(m2·d))、水力停留时间(0.3~0.8 d)、进水COD(120~520 mg/L)、生物膜厚度(100~600 μm) 数学建模 [42]
    2 曝气方式(间歇曝气,Int4+4,Int0.25+0.25) 实验室规模研究 [45]
    3 曝气方式(间歇曝气,Int6+6,Int11+1,Int9+3,Int6+2,Int1+1) 实验室规模研究 [46]
    4 生物膜厚度(0~1 000 μm) 数学建模 [47]
    5 ρ(C)/ρ(N)(3.00±0.14,1.67±0.07) 实验室规模研究 [48]
    7 传质方向(纵向传质) 数学建模 [49]
    注:Inton+off表示间歇曝气过程中,on为曝气时间,off为停止曝气或曝入氮气时间,单位为h。
    下载: 导出CSV
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  • 收稿日期:  2024-07-03
  • 修回日期:  2024-08-27
  • 刊出日期:  2025-03-09

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