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关键词： Unsteady-state   Diurnal flow   Capital cost   Membrane design  

摘要： In this study, the impact of peak flow on anaerobic membrane bioreactor operation is investigated to establish how system perturbation induced by diurnal peaks and storm water flows will influence membrane permeability. Good permeability recovery was attained through increasing gas sparging during peak flow, which was explained by the transition in critical flux of the suspension at higher shear rates. However, supra-critical fluxes could also be sustained, provided peak flow was for a short duration. We suggest longer durations of supracritical operation could be sustained through introduction of reactive fouling control strategies (e.g. TMP setpoint control). An initial flux below the critical flux, prior to the introduction of peak flow, was advantageous to permeability recovery, suggesting membrane 'conditioning' is important in governing recoverability following peak flow. The importance of conditioning was confirmed through analysis of multiple peak flow events in which the loss of permeability following each peak-flow event was increasingly negligible, and can be ascribed to the arrival of a steady-state in membrane surface deposition. Whilst responding to peak flow with increased gas sparging has been shown effective, the energy demand is considerable, and as such a pseudo dead-end filtration strategy was also evaluated, which required only 0.04 kWhm(-3) of energy for gas sparging. Comparison of both filtration modes identified comparable fouling rates, and the feasibility of a low energy gas sparging method for peak flow management that has successfully enabled supra-critical fluxes to be achieved over long-periods in other MBR applications. Importantly, membrane area provides the highest contribution toward capital cost of AnMBR. The potential to turn-up flux in response to peak-flow has been identified in this study, which suggests membrane area can be specified based on average flow rather than peak flow, providing substantial reduction in the capital co

摘要： P24-7

摘要： P6-2

摘要： P25-8

关键词： Computational fluid dynamics   wall shear stress   mechanical stimulation   bone tissue mineralisation  

摘要： In bone tissue engineering experiments, fluid-induced shear stress is able to stimulate cells to produce mineralised extracellular matrix (ECM). The application of shear stress on seeded cells can for example be achieved through bioreactors that perfuse medium through porous scaffolds. The generated mechanical environment (i.e. wall shear stress: WSS) within the scaffolds is complex due to the complexity of scaffold geometry. This complexity has so far prevented setting an optimal loading (i.e. flow rate) of the bioreactor to achieve an optimal distribution of WSS for stimulating cells to produce mineralised ECM. In this study, we demonstrate an approach combining computational fluid dynamics (CFD) and mechano-regulation theory to optimise flow rates of a perfusion bioreactor and various scaffold geometries (i.e. pore shape, porosity and pore diameter) in order to maximise shear stress induced mineralisation. The optimal flow rates, under which the highest fraction of scaffold surface area is subjected to a wall shear stress that induces mineralisation, are mainly dependent on the scaffold geometries. Nevertheless, the variation range of such optimal flow rates are within 0.5-5 mL/min (or in terms of fluid velocity: 0.166-1.66 mm/s), among different scaffolds. This approach can facilitate the determination of scaffold-dependent flow rates for bone tissue engineering experiments in vitro, avoiding performing a series of trial and error experiments. (C) 2018 The Authors. Published by Elsevier Ltd.

关键词： Anaerobic membrane bioreactor   Filtration characteristics   Membrane fouling   Sulfate reduction   Sulfide  

摘要： Sulfate-reducing bioprocesses can be used in the treatment of sulfate-containing industrial effluents including mining, metallurgical and food industries. Although membrane bioreactors (MBAs) have been studied for anaerobic wastewater treatment, sulfidogenic anaerobic MBAs (AnMBRs) received little or no attention. The aim of this study was to evaluate the performance of sulfate-reducing AnMBR and investigate the membrane foulants and filtration characteristics. Sulfate reduction and COD oxidation efficiencies exceeded 90% when the reactor was fed with a synthetic sulfate-rich (2000 mg/L) wastewater with COD/sulfate ratio of 0.75. Long-term filtration performance was evaluated using several filterability tests. Deposition of high molecular weight soluble organics and S, Si, Fe, Cu, Na, and Mg were detected in the cake layer. The formation of metal-sulfide precipitates was the main reason for heavy metal deposition on the membrane surface. Desulfovibrio-like sulfate reducing bacteria was detected in the bioreactor. Results showed that sulfate-reducing AnMBR offers potential for real scale applications.

关键词： Membrane bioreactor (MBR)   qPCR   Fungi   Foaming   Redundancy analysis  

摘要： The abundance of fungi in a full-scale membrane bioreactor (MBR) treating urban wastewater and experiencing seasonal foaming was assessed by quantitative PCR (qPCR), comparing three different sets of widely used universal fungal primers targeting the gene encoding the small ribosomal subunit RNA, 18S-rDNA, (primers NS1-Fung and FungiQuant) or the internal transcribed spacer ITS2 (primers ITS3-ITS4). Fungi were a numerically important fraction of the MBR microbiota (>= 10(6) 18S-rDNA copies/L activated sludge), and occurred both in the aerated and anoxic bioreactors. The numbers of copies of fungal markers/L activated sludge calculated using the NS1-Fung or ITS3-ITS4 primer sets were up to 2 orders of magnitude higher than the quantifications based on the FungiQuant primers. Fungal 18S-rDNA counts derived from the FungiQuant primers decreased significantly during cold seasons, concurring with foaming episodes in the MBR. Redundancy analysis corroborated that temperature was the main factor driving fungi abundance, which was also favored by longer solid retention time (SRT), lower chemical oxygen demand/biochemical oxygen demand at 5 days (COD/BOD5) of influent water, and lower biomass accumulation in the MBR.

关键词： 乳品废水   厌氧膜生物反应器   CODCr  

摘要： 采用厌氧膜生物反应器(AnMBR)对乳品废水进行处理,装置连续运行100d,研究了不同进水COD_(Cr)浓度(3 000、5 000、7 000、9 000 mg/L)对出水水质及反应器内污泥特性的影响,并与常规厌氧生物反应器的处理效果进行对比。结果表明,温度为35℃,HRT为48h时,COD_(Cr)去除率和氨化率随着进水COD_(Cr)浓度的降低而升高,最高可达89%和38%以上。TN去除率随着进水COD_(Cr)浓度的增加先增高后降低,在7 000 mg/L条件下,去除率为55%。装置在运行过程中,MLVSS/MLSS平均值约为0. 7,SVI值在60～80 m L/g的范围内,污泥具有良好的活性与沉降性。AnMBR与常规厌氧生物反应器相比,在处理高浓度乳品废水时运行更加稳定,耐冲击负荷能力更强,出水水质更好。

关键词： 游离氨   硝化杆菌   比耗氧速率   动力学   宏基因组   生物反应器   需氧  

摘要： 为探究游离氨(FA)对亚硝酸盐氧化细菌中硝化杆菌属(Nitrobacter)活性抑制动力学影响,本试验采用序批式活性污泥(SBR)反应器,在通过改变系统进水FNA浓度达到富集Nitrobacter基础上,以富含Nitrobacter污泥为对象(宏基因组物种注释和丰度分析显示Nitrobacter占细菌总数40.3%),基于批次试验,考察不同FA浓度梯度下亚硝酸盐氧化过程Nitrobacter比耗氧速率(SOUR)变化规律,进而采用非基质抑制动力学模型对试验数据进行拟合。结果表明,当FA>7.3 mg·L^(-1)时,SOUR随着FA浓度的升高而降低。尤其当FA浓度高于22.2 mg·L^(-1)时,SOUR降为0gN·(g VSS·d)^(-1),最大比耗氧速率为0.62 g N·(g VSS·d)^(-1)。此外,基于Nitrobacter活性抑制程度判断,FA抑制Nitrobacter活性抑制类型符合非竞争性可逆抑制动力学。

关键词： 生物反应器   转速   温度   pH   DO  

摘要： 动物细胞培养技术的迅速发展推进了生物制药领域生产的发展,动物细胞大规模培养技术备受关注。生物反应器是动物细胞大规模培养中不可代替的主要设备,动物细胞生物反应器是模拟生物的体内环境,为了得到动物细胞高密度增殖的效果,并且也要保证动物细胞高效分泌的目的,需要对其培养的运行参数进行控制,可以控制的运行参数有:转速、温度、pH、DO等,本文主要对动物生物反应器培养常用参数进行综述。