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关键词： Membrane bioreactor   Nutrients   Membrane fouling   Microbial community  

摘要： The application of membrane bioreactor (MBR) processes for conventional, municipal and industrial wastewater treatment [e.g., biological oxygen demand (BOD) reduction] is well established. The research and development of MBR processes for nitrogen removal is more recent. To date, no thorough review of MBR technology for nitrogen removal from wastewater has been carried out. The review presented here provides an overview of MBR process configurations for the removal of nitrogen based on conventional nitrogen-removal pathways (i.e., nitrification/denitrification) as well as alternative nitrogen-removal pathways, such as anaerobic ammonium oxidation (ANAMMOX). A wide range of system configurations have been explored for the application of MBR for nitrogen removal, including immersed or side-stream membrane configurations, single or multichamber processes, and the application of fixed and moving bed biofilms. Operating variables play an important role in controlling nitrogen removal and fouling, especially feed composition (particularly the carbon : nitrogen ratio), membrane characteristics, solids retention time, and hydraulic retention time. Modeling approaches for predicting nitrogen removal using MBR are evolving and are better able to represent key process differences in MBRs compared to conventional activated sludge. Although several challenges remain (e.g., membrane fouling, cost, and energy consumption), a number of opportunities exist (such as new reactor configurations, new microbial pathways, and development of a better understanding of process function through metaomic approaches) that may lead to the broader application of MBR processes for nitrogen removal from municipal wastewater in the future.

关键词： Anaerobic hybrid membrane bioreactor   Landfill leachate   Attached growth   Membrane fouling   Ceramic membrane  

摘要： In the present study, the treatment of synthetic landfill leachate was carried out using a lab-scale anaerobic hybrid membrane bioreactor (An-HMBR). The reactor was operated for 250 days at two days of hydraulic retention time (HRT). Average chemical oxygen demand (COD) removal efficiency was >= 88% at steady-state conditions at 100% raw leachate. As organic loading rate (OLR) increased from 1.6 to 13.9 Kg COD m(-3) d(-1), flux gradually declined from 70 to 52 L/m(2) h (LMH) within 250 days. Chemical membrane cleaning enhanced the flux up to 75% of the initial flux at the final stage of the reactor. Reversible fouling (>90%) dominated over irreversible fouling (<8%). Membrane fouling was mainly caused by extracellular polymeric substances (EPS) fraction, which resulted in cake layer formation on the ceramic membrane used in the An-HMBR system. Membrane resistance increased with variables in the following order OLR > MLSS (mixed liquor suspended solids) > EPS > SMP (soluble microbial products). A nonlinear regression model developed for prediction of membrane resistance at different OLR can predict with an error of +/- 7%. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： 非溶解性氧化还原介体   催化   偶氮染料   厌氧生物降解   生物反应器  

摘要： 偶氮染料是印染等行业废水的主要污染物之一,其有效生物处理往往需要厌氧-好氧的结合。厌氧生物处理是偶氮染料降解的限速步骤,故可采用氧化还原介体(RM)催化加速厌氧生物降解偶氮染料的反应。文中分析了溶解性RM的经济性和实用性,得出了溶解性RM不适宜工程应用的结论;综述了溶解性RM和非溶解性RM在厌氧生物还原偶氮染料中的催化效果以及优缺点;概述了非溶解性RM与厌氧反应器和膜生物反应器耦合的相关应用。

关键词： Chromium removal   Mixed culture   Magnetic field   Desorption   Effluent treatment  

摘要： Two chromium removal experiments were performed in bioreactors with and without a magnetic field under the same *** release of the chromium present in the biomass was tested in two experiments one with the initial pH of the medium and one with pH *** objective was to remove Cr(Ⅵ)and total Cr from the effluent,this was carried out by placing biological treatments of synthetic effluent contaminated with 100 mg/L of Cr(Ⅵ)in a bioreactor with neodymium magnets that applied a magnetic field(intensity85.4 mT)to the mixed *** removal of Cr(Ⅵ)was approximately 100.0%for the bioreactor with a magnetic field and 93,3%for the bioreactor without a magnetic field for9 hr of recirculation of the synthetic effluent by the *** removal of total Cr was61.6%and 48.4%,with and without a magnetic field,respectively;for 24 *** desorption of Cr(VI)in the synthetic effluent was 0.05 mg/L,which is below the limit established by Brazilian legislation(0.1 mg/L)for the discharge of effluent containing Cr(Ⅵ)into bodies of *** results obtained for the removal of chromium in synthetic effluent suggested that there was no significant influence on the viable cell count of the mixed *** desorption of Cr(Ⅵ)in synthetic effluent after bioadsorption of chromium by the mixed culture in the process of removal of chromium in bioreactors with and without a magnetic field was not significant in either of the experiments with different initial pHs.

关键词： Biogas purification   Membrane bioreactor   Siloxanes   Volatile organic compounds  

摘要： Sewage biogas valorization to different energy applications is hampered by the presence of volatile methyl siloxanes. Despite the high operating costs, adsorption onto activated carbon is the most implemented technology for siloxane removal from biogas. In order to purify biogas sustainably, the current work explores the diffusion of siloxanes (octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane) together with other biogas impurities (limonene, toluene and hexane) through polydimethylsiloxane membranes. Abiotic tests revealed transport efficiencies above 75% towards a clean air stream for most compounds, although the transport of the most hydrophobic pollutants was challenged when water was circulated through the shell side of the membrane. Moreover, the performance of a hollow-fiber membrane bioreactor, inoculated with anerobic active sludge, was evaluated towards biogas purification in anoxic conditions. Toluene and limonene were successfully degraded, hexane's removal efficiency was positively correlated with the residence time, and siloxanes removal was achieved up to 21%. CO2 was detected in the outlet gas as the mineralization product as well as some byproducts from the degradation of limonene and siloxanes. The presence of 1% of O-2 in the gas, as a strategy to substitute NO3-, efficiently supported high removal for volatile organic compounds and moderate for siloxanes, which would ultimately reduce the operating costs of the technology.

关键词： 曝气冲刷   膜生物反应器   剪切力   膜污染   流体力学   生物化学  

摘要： 膜污染是膜生物反应器(MBR)进一步推广应用的瓶颈问题。曝气冲刷是一种操作简单、无二次污染的MBR膜污染控制技术,但在缓解膜污染的同时也显著增加了系统的运行能耗。优化曝气能耗需深入理解膜污染控制的流体力学机理和生物化学机理。重点综述了曝气冲刷通过剪切力去除膜表面污垢的作用机理,以及曝气冲刷影响污泥混合液的作用机理。在综述的基础上展望了未来研究的发展方向。

关键词： Membrane bioreactor   Biofouling   Quorum sensing   Quorum quenching   Backwashing   Permeate flux  

摘要： Filtration and backwashing during the operation of a membrane bioreactor (MBR) physically induce the cyclic attachment and detachment of microbes on the membrane surface. Thus, permeate flux and backwashing affect the microbial quorum sensing (QS) and quorum quenching (QQ) processes taking place in a biocake layer on a membrane surface. From an analysis of the time to reach a transmembrane pressure (TMP) of 40 kPa (TTMP) under different water flux levels, 20 or 40 liter per square meter per hour (LMH), with QQ beads or vacant beads in MBRs, it was found that the accelerated deposition of microbial cells on membrane surfaces at 40 LMH significantly reduced the time for bacteria to initiate QS and, thus, allowed less room for QQ compared with the results at 20 LMH. On the application of backwashing, the TMP jump with QQ beads is more delayed than that with vacant beads in both the 20 and 40 LMH cases. However, the extracellular polymeric substance (EPS) level with backwashing decreased at 20 LMH but increased at 40 LMH regardless of bead type because the reduced fouling rate caused by backwashing provided the bacteria with more time to activate QS, facilitating active EPS production when backwashing is employed at 40 LMH. A biocake porosity analysis revealed that when backwashing was applied, the porosity increased significantly at 40 LMH but remained nearly unchanged at 20 LMH. It is suggested that, at the higher flux level, backwashing allowed enough time for bacteria to initiate QS and, thus, form biofilm with a porous mushroom-like structure. Similarly, the inhibition of QS through the addition of QQ beads indicated dependence on the permeate flux and backwashing. These results suggest that a hydrodynamic condition near the membrane surface could have a considerable influence on the activation of microbial QS, which in turn can affect membrane biofouling in an MBR.

关键词： 膜生物反应器   厌氧氨氧化   膜污染  

摘要： 为探究膜生物反应器(MBR)进行厌氧氨氧化的可行性及性能,通过逐渐提高进水NH4^+-N、NO2^--N的含量和降低HRT,成功启动了自流出水式MBR厌氧氨氧化过程,分析了反应器脱氮效果和厌氧氨氧化污泥特性,并采用扫描电镜和X射线光电子能谱中空纤维膜表面进行分析。结果表明,经过60 d的启动,NH4^+-N、NO2^--N和TN的去除率分别达到96.22%、99.91%和81.66%,TN去除负荷最大可达到330 g/(m^3·d)。在启动过程中,污泥颜色逐渐变为红褐色;中空纤维膜表面厌氧氨氧化菌呈不规则的椭球状,结构紧凑;MBR运行稳定阶段末期中空纤维膜表面C、N和Ca特征峰增多,是膜污染化学组分的主要构成元素。

关键词： CFD   气升式生物反应器   流场   液相速度   气含率  

摘要： 利用计算流体力学(CFD)软件Fluent及欧拉--欧拉双流相模型对两种进料管不同的气升式生物反应器内流场进行数值模拟。通过对仿真出的液相速度云图、速度矢量图及气含率云图的分析,得到了这两种反应器内气液二相的流动情况,并发现双进料管气升式生物反应器有更好的混合传质性能。CFD在气升式反应器的优化与放大方面具有重要的指导意义。

关键词： 潮汐式生物反应器   轮状病毒   Vero细胞  

摘要： 目的建立潮汐式生物反应器CelCradle^TM培养轮状病毒的工艺。方法利用500 mL的潮汐式生物反应器CelCradle^TM培养Vero细胞,通过葡萄糖含量监测及活细胞计数进行换液,待活细胞数目达2.75×10^9个时,分别按0.01、0.05、0.1和0.2 MOI接种轮状病毒ZTR-68株,于37℃,5%CO2培养箱中培养7 d,每天取样,聚丙烯酰胺凝胶电泳检测病毒基因组核酸带型,免疫荧光法检测病毒增殖情况,透射电镜观察病毒的形态结构,蚀斑法检测病毒滴度,确定生物反应器CelCradle^TM培养轮状病毒的最适MOI。结果在CelCradle^TM反应器中接种3×108个Vero细胞,经7 d培养,活细胞数目可达2.75×10^9个;以0.05 MOI轮状病毒ZTR-68接种Vero细胞的病毒基因组带型与转瓶培养的保持一致,感染后3~5 d,轮状病毒荧光阳性细胞数目最多,电镜下可见形态结构完整的轮状病毒颗粒;以0.05 MOI接种轮状病毒ZTR-68株96 h病毒滴度最高,为7.7 LogPFU/mL。结论初步建立了潮汐式生物反应器CelCradle^TM培养轮状病毒的工艺,为进一步大规模生产轮状病毒灭活疫苗奠定了实验基础。