内循环生物流化床曝气过程氧传质特性研究

针对水-空气-高分子颗粒三相体系,测试了内循环好氧生物流化床曝气过程中气-液相间氧传递的体积传质系数KLa,分析了操作参数(进气量QG、固含率εs和升降流区截面积比Ar/Ad)对氧传质系数KLa的影响。结果表明,KLa随着进气量的提高呈线性增加趋势;固含率对KLa有正反两方面的作用,存在一个较适宜的固含率使氧传质效率达到最高;随升降流区截面积比Ar/Ad的增大,KLa随之提高。基于KLa影响因素的分析对实验数据进行拟合,建立了关于体积传质系数KLa的关联式:Kd=2.23×10-6Reb0.582Ab0.976εs0.016。该关联式预测结果与实验数据吻合良好,对类似流化床反应器的设计有一定参考价值。     

气升式内循环蜂窝陶瓷反应器的氧传质特性

气升式内循环蜂窝陶瓷反应器(IAL-CHS)的氧传质性能测定结果表明,IAL-CHS反应器与普通气升式反应器相比氧传递能力更强,氧传质效果更好,氧转移效率更高。进行清水充氧试验分别采用0.006、0.018、0.025、0.05、0.10、0.15、0.20 m.3h-1的曝气强度,最初IAL-CHS反应器的氧传递系数(Kla)20与曝气强度呈正相关,在0.1m3.h-1的曝气强度下氧传质系数增至最大值,之后再提高曝气强度反应器的氧传递系数反而降低。然而反应器的氧转移效率EO2值始终随着曝气强度的升高而减少。     

SBBR与SBR氧传质特性比较研究

在试验条件相同的情况下,进行了序批式膜生物反应器SBBR与SBR的清水充氧试验,氧传质特性比较研究结果表明:当曝气强度为0.3m3/h时,SBBR的(KLa)20和Eo2值均为SBR的1.59倍。SBBR具有更好的氧传质能力和更高的氧转移效率。     

好氧氨氧化生物膜内氧传质特性及影响因素

采用理论计算和实验测试相结合的方法,对流化床反应器中好氧氨氧化生物膜内溶解氧传质特性及影响因素进行了分析。建立了综合考虑反应-扩散-对流作用的一维模型,计算结果表明:溶解氧所能到达的生物膜厚度受渗流速度等因素的影响;增大渗流速度、扩散系数和进水底物浓度均可以提高膜内溶解氧浓度的最大值。建立了序批式流化床生物膜反应器,获得了高于80%的氨氮转化率,实现了好氧氨氧化生物膜的成功挂膜,获得生物膜厚度为0.1～0.3 mm,采用微电极测试了膜内溶解氧浓度。实验测试和模型计算结果表明,溶氧浓度沿生物膜厚度方向均呈现出抛物线形的不均匀下降趋势,且当扩散系数为2.2×10–4 m2/s和渗流速度为6.0 mm/s时,测试结果和计算数值具有较好的吻合度。     

膜生物膜反应器的研究与应用

为提高反应器中氧的利用率,高效去除水中的有机碳和氨氮,介绍了一种新型的水处理反应器-膜生物膜反应器,该反应器通过膜分离技术与生物膜技术相接合,可获得100%氧利用率.并且能够起到快速降解挥发性有机物和高效去除有机碳和氨氮的作用,是一种很有发展潜力的污水处理工艺.     

一种新型城镇污水处理一体化间歇曝气生物膜反应器

文中介绍了一种新型城镇污水处理一体化间歇曝气生物膜反应器的工艺系统、技术原理以及实际处理效果,试验结果显示,该工艺对COD、氮、磷均具有良好的去除效果,是一项具有广阔应用前景的新工艺。     

高效好氧生物技术及其在污水处理中的应用

近年来好氧生物技术得到了不断的发展,出现许多高效的、可处理难降解甚至有毒废水的好氧生物技术.本文主要综述了3种从不同方面实现高效降解有机废水的好氧生物处理技术:移动床生物膜反应器、加压曝气技术以及膜生物反应器在废水处理中的应用进展,并概括了各自的优缺点,最后对这3种生物工艺的发展进行了展望.     

生物膜法A2/O2焦化废水处理系统中好氧反应器工艺特性

以焦化厂废水处理系统气浮设备出水为水源,在中试规模上研究了生物膜法A2/O2系统中好氧反应器的工艺特性和效果.研究结果表明,系统进水COD为1 000～2 200 mg/L,NH3-N质量浓度为200~400mg/L,水解酸化反应器HRT为20 h,缺氧反应器HRT为24 h,一级好氧反应器和二级好氧反应器HRT均为48 h,二级好氧反应器硝化液回流比为3,一级好氧反应器COD容积负荷为0.40 ks/(m3·d),二级好氧反应器COD容积负荷<0.07 kg/(m3.d).NH3-N容积负荷为0.022 kg/(m3·d)时,生物膜法A2/O2系统处理出水COD和NH3-N浓度可以同时达到<污水综合排放标准>(GB 8978-1996)中的一级排放标准.     

内循环好氧生物流化床处理糖业废水试验研究

应用内循环好氧生物流化床对COD(cr)和NH3-N质量浓度分别为350-580mg/L和7-12mg/L的甘蔗制糖废水进行处理.以人工合成的高分子颗粒作生物膜载体,通过改变空气流量和水力停留时间,考察不同操作条件下对不同浓度废水的COD(cr)和NH3-N去除效果.试验表明,在进气量为40L/h、水力停留时间为3-4...     

曝气生物膜反应器处理受污染河道水体实验研究

以某受污染河道水体为研究对象,设计了曝气生物膜反应器(MABR),探讨了主要污染物如COD、氨氮、TN、DO等降解及变化规律。结果表明,MABR系统运行稳定,有较高的抗冲击性能能力,对河道受污染的主要污染物有迅速的去除能力和显著的去除效果,出水水质能稳定达到GB 3838-2002地表水IV类标准。在MABR膜表面生物反应时,需添加60～80 mg/L的碳源,同时维持不高于3 mg/L的DO质量浓度,提高反硝化效果,控制TN含量;COD低于20 mg/L时,深度脱除速率下降。     

用于污水处理的柔性纤维膜反应器氧传递及动力学研究

A flexible fibre biofilm reactor was developed for treatment of organic wastewaters. The hydrodynamic characteristics and mass transfer coefficients of oxygen were studied and compared with those of the conventional activated sludge processes. Tracer experiments were performed to obtain the residence time distributions of the reactors. The results indicated that both reactors could be treated as mixed flow reactors. The effects of flow rates of water and air on the overall mass transfer coefficient of oxygen were investigated, and the correlations between the mass transfer coefficient and the ratio of flow rates were obtained. Compared to the conventional activated sludge reactor, the mass transfer coefficients in the flexible fibre reactor were similar to but slightly lower, and less sensitive to the variation in the ratio of flow rates. It indicated that the fibre packing in the reactor hindered the oxygen transfer to some extent.     

移动床生物膜反应器污水处理工艺的研究现状及展望

简述了移动床生物膜反应器的工艺原理和特点,详细介绍了国内外移动床生物膜反应器在生活污水、工业废水和生物脱氮方面的研究现状。通过比较不同生物膜法对焦化废水的处理效果,指出移动床生物膜反应器是一种经济、高效的焦化废水处理方法,最后提出移动床生物膜反应器在实际工程应用和理论研究中的发展趋势。     

移动床生物膜反应器污水处理技术简介

简述了移动床生物膜反应器的工艺原理和特点,详细介绍了国内外移动床生物膜反应器的研究现状,最后提出移动床生物膜反应器在实际工程应用和理论研究中的发展趋势。     

Three-Dimensional Stratification of Bacterial Biofilm Populations in a Moving Bed Biofilm Reactor for Nitritation-Anammox

Moving bed biofilm reactors (MBBRs) are increasingly used for nitrogen removal with nitritation-anaerobic ammonium oxidation (anammox) processes in wastewater treatment. Carriers provide protected surfaces where ammonia oxidizing bacteria (AOB) and anammox bacteria form complex biofilms. However, the knowledge about the organization of microbial communities in MBBR biofilms is sparse. We used new cryosectioning and imaging methods for fluorescence in situ hybridization (FISH) to study the structure of biofilms retrieved from carriers in a nitritation-anammox MBBR. The dimensions of the carrier compartments and the biofilm cryosections after FISH showed good correlation, indicating little disturbance of biofilm samples by the treatment. FISH showed that Nitrosomonas europaea/eutropha-related cells dominated the AOB and Candidatus Brocadia fulgida-related cells dominated the anammox guild. New carriers were initially colonized by AOB, followed by anammox bacteria proliferating in the deeper biofilm layers, probably in anaerobic microhabitats created by AOB activity. Mature biofilms showed a pronounced three-dimensional stratification where AOB dominated closer to the biofilm-water interface, whereas anammox were dominant deeper into the carrier space and towards the walls. Our results suggest that current mathematical models may be oversimplifying these three-dimensional systems and unless the multidimensionality of these systems is considered, models may result in suboptimal design of MBBR carriers.     

外循环三相流化床处理染料废水

利用外循环三相生物流化床设计准则，通过小试规模的流化床对经预处理的模拟含染料废水和工业废水进行处理，结果表明：在4 h内增加水力停留时间(HRT)，可提高化学需氧量(CODcr)去除率. 气、液、固三相的循环运动使流化床具有较强抗冲击负荷能力，生物膜厚在100~350 mm范围内，进水CODcr浓度在较宽范围内波动时，对出水CODcr去除率影响不大，都能维持在80%以上.     

内循环生物流化床处理氮、磷废水的试验研究

采用内循环生物流化床系统,进行处理氮、磷废水的试验研究,通过控制曝气时间和溶解氧浓度,能同时达到脱氮除磷的性能.对于氮、磷废水,进水COD在352～1048 mg·L-1,TN在46.9～76.4 mg·L-1,TP在5.8～14.4 mg·L-1时,COD 、TN、TP去除率分别为92 %、80 %、93 %,出水可达到国家二级排放标准.     

The Effect of Bed Temperature on Mass Transfer between the Bubble and Emulsion Phases in a Fluidized Bed

The rate of interphase mass transfer between the bubble and emulsion phases of a bubbling fluidized bed is of primary importance in all models for fluidized bed reactors. Many experimental studies have been reported, however, all these investigations have been carried out in fluidized beds operated at room temperature. In this work, the effect of the bed temperature on the interphase mass transfer is reported. Single bubbles containing argon – used as a tracer – were injected into an incipiently fluidized bed maintained at the required temperature. The change in argon concentration in the bubble was measured using a suction probe connected to a mass spectrometer. The effects of bed particle type and size, bubble size, and bed temperature on the mass transfer coefficient were examined experimentally. The interphase mass transfer coefficient was found to decrease with the increase in bed temperature and bubble size, and increase slightly with increase in particle size. Experimental data obtained in this study were compared with some frequently used correlations for estimation of the mass transfer coefficient.     

新型内循环生物流化床的流体力学性能

以挂膜后的活性炭为载体,在不同投加率下,研究了典型内循环生物流化床的水力特性及充氧特性。流体循环时间及混合时间随气速及载体投加量增加而缩短;循环时间随液速增大而缓慢减小;混合时间随液速变化规律较复杂;各区气相含率随气速及载体含率的增大而升高;且受气速影响显著;KLa随气速、载体投加率增加总趋势为增大,但幅度较小。     

循环流化床气固传质实验研究

This study is devoted to gas-solid mass transfer behavior in heterogeneous two-phase flow. Experiments were carried out in a cold circulating fluidized bed of 3.0m in height and 72mm in diameter with naphthalene particles. Axial and radial distributions of sublimated naphthalene concentration in air were measured with an online concentration monitoring system HP GC-MS. Mass transfer coefficients were obtained under various operating condition, showing that heterogeneous flow structure strongly influences the axial and radial profiles of mass transfer coefficients. In the bottom dense region, mass transfer rate is high due to intensive dynamic behavior and higher relative slip velocity between gas and clusters. In the middle transition region and the upper diluter region, as a result of low mass transfer driving force and the influence of flow structure, mass transfer rate distribution becomes non-uniform. In conclusion, among the operating parameters influencing mass transfer coefficients, the superficial gas velocity is the most important factor and the solid circulation rate should be also taken into account.