scholarly journals Mechanism investigation of virus removal in a membrane bioreactor

2006 ◽  
Vol 6 (6) ◽  
pp. 51-59 ◽  
Author(s):  
X. Zheng ◽  
J.X. Liu
Keyword(s):  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Membrane Pore ◽  
Virus Removal ◽  
Pore Sizes ◽  
Pathogenic Viruses ◽  
Mean Size ◽  
Membrane Modules ◽  
Membrane Pore Size ◽  
Model Virus

Virus removal in a membrane bioreactor (MBR) by gravity drain was studied. Coliphage f2 (mean size of 25 nm), which is similar in size to human enteric pathogenic viruses, was selected as a model virus. Two microfiltration membrane modules with pore sizes of 0.22 μm and 0.1 μm were applied to investigate the effects of membrane pore size on the virus rejection. The MBR with these modules could reject virus in a range of 2.6–5.1 logs. The experimental results showed that the mechanisms of virus removal in the MBR involved rejection and inactivation. The virus rejection depended mainly on the dynamic layer on the membrane surface (not membrane itself) because virus rejection by the membrane modules with pore sizes of 0.1 μm and 0.22 μm were similar. The microbial activity and the aeration oxidation were the two important factors for the virus inactivation. It was found that the inactivation of coliphage f2 was much more rapidly in activated sludge mixed liquor than in clean water, and the effect of aeration was significant.

scholarly journals Theoretical Evaluation of Polyelectrolyte Layering during Layer-by-Layer Coating of Ultrafiltration Hollow Fiber Membranes

Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 106
Author(s):  
Jakob Stumme ◽  
Omjothi Ashokkumar ◽  
Saskia Dillmann ◽  
Robert Niestroj-Pahl ◽  
Mathias Ernst
Keyword(s):  
Film Growth ◽  
Membrane Surface ◽  
Layer Growth ◽  
Research Field ◽  
Porous Membranes ◽  
Layer By Layer ◽  
Theoretical Evaluation ◽  
Membrane Pore ◽  
Active Research ◽  
Membrane Pore Size

Layer-by-layer (LbL) modification of porous membranes for water filtration has become an active research field in the past few years. Different mechanisms regarding polyelectrolyte film growth, swelling and smoothing, transport through these films, etc., have been studied. Although there are conjectures, it is not yet fully understood where the polyelectrolyte layering takes place when modifying porous membranes, either within the pores or on top of the porous material. This study presents a theoretical approach to investigate the dominant layer buildup regime between pore-dominated vs. layer-dominated growth of polyelectrolytes on porous membranes without mechanically interfering or damaging the membrane material. For this, fouling mechanism processes are used as an analogy. The presented approach gives a new insight into layering conformation and might be helpful to investigate the interaction between the membrane surface and the PE film. Moreover, the MgSO4 rejection behavior of two types of modified membranes was investigated: one with an initial pore-dominated layer growth followed by a layer-dominated film growth; the other one with a completely layer-dominated film growth. The data confirm that a rejection for MgSO4 could only be achieved in the regime of layer-dominated film growth. Additionally, when layer-dominated film growth prevails from the early stages of the coating process, permeability values are higher at similar MgSO4 rejection rates compared to an initial pore-dominated and then layer-dominated film growth. Accordingly, the interaction between the membrane pore size and molecular weight of the polyelectrolytes in the coating solutions plays an important role during LbL coating.

scholarly journals Simulation and optimization of airlift external circulation membrane bioreactor using computational fluid dynamics

2014 ◽  
Vol 69 (9) ◽  
pp. 1846-1852 ◽  
Author(s):  
Zhang Qing ◽  
Xu Rongle ◽  
Zheng Xiang ◽  
Fan Yaobo
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Membrane Surface ◽  
Aeration Tank ◽  
Low Velocity ◽  
Simulation And Optimization ◽  
External Circulation ◽  
Membrane Modules

The airlift external circulation membrane bioreactor (AEC-MBR) is a new MBR consisting of a separated aeration tank and membrane tank with circulating pipes fixed between the two tanks. The circulating pipe is called a H circulating pipe (HCP) because of its shape. With the complex configuration, it was difficult but necessary to master the AEC-MBR's hydraulic characteristics. In this paper, simulation and optimization of the AEC-MBR was performed using computational fluid dynamics. The distance from diffusers to membrane modules, i.e. the height of gas–liquid mixing zone (hm), and its effect on velocity distribution at membrane surfaces were studied. Additionally, the role of HCP and the effect of HCP's diameter on circulation were simulated and analyzed. The results showed that non-uniformity of cross-flow velocity existed in the flat-plate membrane modules, and the problem could be alleviated by increasing hm to an optimum range (hm/B ≥ 0.55; B is total static depth). Also, the low velocity in the boundary layer on the membrane surface was another reason for membrane fouling. The results also suggested that HCP was necessary and it had an optimum diameter to make circulation effective in the AEC-MBR.

Treatment of molasses wastewater in a membrane bioreactor: Influence of membrane pore size

2010 ◽  
Author(s):  
Muhammad R. Bilad ◽  
Priscilla Declerck ◽  
Anna Piasecka ◽  
Louise Vanysacker ◽  
Xinxin Yan ◽  
...  
Keyword(s):  
Pore Size ◽  
Membrane Bioreactor ◽  
Membrane Pore ◽  
Molasses Wastewater ◽  
Membrane Pore Size

Occurrence and removal of microbial indicators from municipal wastewaters by nine different MBR systems

2012 ◽  
Vol 66 (4) ◽  
pp. 865-871 ◽  
Author(s):  
Zakir M. Hirani ◽  
James F. DeCarolis ◽  
Geno Lehman ◽  
Samer S. Adham ◽  
Joseph G. Jacangelo
Keyword(s):  
Fecal Coliform ◽  
Polyvinylidene Fluoride ◽  
Coliform Bacteria ◽  
Membrane Pore ◽  
Microbial Indicators ◽  
Membrane Materials ◽  
Pore Sizes ◽  
Wide Range ◽  
Membrane Pore Size ◽  
The Impact

Nine different membrane bioreactor (MBR) systems with different process configurations (submerged and external), membrane geometries (hollow-fiber, flat-sheet, and tubular), membrane materials (polyethersulfone (PES), polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE)) and membrane nominal pore sizes (0.03–0.2 μm) were evaluated to assess the impact of influent microbial concentration, membrane pore size and membrane material and geometries on removal of microbial indicators by MBR technology. The log removal values (LRVs) for microbial indicators increased as the influent concentrations increased. Among the wide range of MBR systems evaluated, the total and fecal coliform bacteria and indigenous MS-2 coliphage were detected in 32, 9 and 15% of the samples, respectively; the 50th percentile LRVs were measured at 6.6, 5.9 and 4.5 logs, respectively. The nominal pore sizes of the membranes, membrane materials and geometries did not show a strong correlation with the LRVs.

scholarly journals Modification of Membranes from Nylon by Microwave Radiation in Argon, Nitrogen and Atmospheric Air

2018 ◽  
Vol 7 (4.36) ◽  
pp. 1054 ◽  
Author(s):  
Dinar D. Fazullin ◽  
Elena A. Kharitonova ◽  
Gennady V. Mavrin ◽  
Ilnar A. Nasyrov
Keyword(s):  
Microwave Radiation ◽  
Membrane Surface ◽  
Microwave Treatment ◽  
Nitrogen Atmosphere ◽  
Specific Productivity ◽  
Nylon Membrane ◽  
Membrane Pore ◽  
Oil Emulsion ◽  
Emulsion Separation ◽  
Membrane Pore Size

Microfiltration thin-film membranes of nylon were treated with microwave radiation within the decimeter wavelength range in air, nitrogen and argon to increase the specific productivity and the degree of the resistant oil emulsion separation due to structural transformations in the surfaces and membrane pores. After the processing of nylon membrane in air, argon and nitrogen, the specific performance of the membranes increases during the filtration of distilled water by 1.3 times. This circumstance is connected, probably with the increase of membrane pore size. And when the oil emulsion is separated, the specific productivity is increased after the treatment in air and oxygen up to 2.3 times, and after the treatment in argon it is decreased by 2 times. The decrease in performance occurs apparently due to the crosslinking of the pores and the surface layer of the membrane. It has been established that the treatment of nylon membranes with microwave radiation in air, nitrogen and argon leads to the decrease of oil emulsion separation degree, which is explained by the membrane surface etching. The worst degree of purification makes 83% and it is observed after the separation of the emulsion with the membrane treated by microwave radiation in a nitrogen atmosphere, when the loss of membrane mass after the microwave treatment was 0.69%. The purification degree from oil is reduced in the least after the treatment in argon medium - 93, and the loss of membrane mass after treatment makes 0.26%. 

scholarly journals Coalescence of Oil Droplets using Sponge-like Structure of Polyvinylidene Fluoride Membranes

2018 ◽  
Vol 23 (1) ◽  
Author(s):  
C. K. Chiam ◽  
M. Nurashiqin ◽  
K. Zykamilia ◽  
N. M. Ismail ◽  
K. Duduku ◽  
...  
Keyword(s):  
Size Distribution ◽  
Polyvinylidene Fluoride ◽  
Produced Water ◽  
Feed Solution ◽  
Transmembrane Pressure ◽  
Oil Droplets ◽  
Membrane Pore ◽  
Pore Sizes ◽  
Phase Inversion Technique ◽  
Membrane Pore Size

This work reports the effect of the membrane pore size distribution on the oil droplets size distribution in permeate using the polyvinylidene fluoride (PVDF) membranes. The sponge-like structures of the PVDF membranes were fabricated via the phase inversion technique using 30% v/v ethanol aqueous solution as coagulation medium. Water and polyethylene glycol (PEG1000) were used as the pore forming additives in the dope solutions. Microfiltration was employed to coalesce the oil droplets at the transmembrane pressure of 2.5 bar. Simulated alkaline-surfactant-polymer (ASP) produced water was tested as the feed solution. Results revealed that the PVDF membranes with sponge-like structure were formed. The additives in the dope solutions have induced the membranes to become thicker due to more porous, spongy and resilient structure. The membrane pore sizes increased with the presence of the additives in the dope solutions especially when larger molecular weight of the additive, i.e., PEG1000 was used. The mode of the oil droplets radius increased from 61.2 nm in the feed solution to 95.1, 356.2 and 1335 nm in the permeates by the corresponding membranes without additive, with water and PEG1000 as the additives. The membranes with larger pore sizes as well as more open structure were able to trap and coalesce more oil droplets which produced larger size of the oil droplets in the permeates.

scholarly journals Research of performance characteristics of membrane modules for wastewater treatment

2020 ◽  
pp. 6-6
Author(s):  
Nikolay A. Makisha
Keyword(s):  
Wastewater Treatment ◽  
Pore Size ◽  
Suspended Solids ◽  
Membrane Filter ◽  
Synthetic Wastewater ◽  
Membrane Pore ◽  
Filtration Membranes ◽  
Ultra Filtration ◽  
Membrane Modules ◽  
Membrane Pore Size

Introduction. The study focuses on the operation of a standalone membrane bioreactor applicable as an alternative to submerged membrane modules widely used as part of small capacity wastewater treatment facilities. Materials and methods. An ultra-filtration membrane was used to perform the research in a laboratory environment. The liquid, exposed to research, represented synthetic wastewater, whose composition was similar to the one of urban wastewaters, and it had varied concentrations of suspended solids (MLSS). The membrane element, produced by Raifil (Republic of Korea), that has capillary ultra-filtration membranes, was used in the experiments. The membrane pore size is 1 micron. The total membrane filter area is one square meter. This membrane module has standard characteristics (pore size, material), typical for ultra-filtration membranes; therefore, we can assume that any further results will not demonstrate any substantial discrepancies, if ultra-filtration membranes made by other manufacturers are used to conduct experiments. Results. The author describes a methodology for the optimization of pressure and MLSS values used in the process of membrane treatment. The author obtained the pressure values at which the amount of suspended solids in the filtered material shows a sharp rise, which means a slip of suspended solids into the filtrate, or a slip of contaminants. The author also identified the operating parameters that ensure maximal capacity. Conclusions. These findings help to outline a roadmap for further research into the optimization of membrane bioreactors (both standalone and submerged units) used in wastewater treatment.

Study on the Effects of Shear Strength and Aeration Method on Membrane Fouling in Vertical A/O-MBR Process

2011 ◽  
Vol 374-377 ◽  
pp. 951-955
Author(s):  
Xiu Bo Chen ◽  
Zhi Qiang Liu ◽  
Xu Hua Liu ◽  
Gai Jing Yu ◽  
Zhi Hua Zhang
Keyword(s):  
Membrane Fouling ◽  
Large Scale ◽  
Membrane Bioreactor ◽  
Positive Impact ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Slowing Down ◽  
Circulation Velocity ◽  
Membrane Modules ◽  
Function Relationship

Vertical Anoxic/Oxic Membrane Bioreactor (A/O-MBR) was used to treat domestic sewage. PVDF hollow fiber membrane has been used in MBR. According to the comparison of intercommunity between three non-Newtonian fluid models (Bingham model, Ostwald model and Herschel-Bulkley model) and the test data, the Ostwald model was chose to describe the function relationship between shear intensity and aeration amount. In order to initiating a circulation velocity and to enhancing the scour to the MBR, the traditional aeration method was changed in this experiment. Two baffles were placed on both sides of the membrane modules, and aeration heads were scattered between two baffles. The influence of shear intensity and new aeration method to membrane fouling was investigated in this paper at shear intensity of 20s-1, 40s-1, 60s-1 and 80s-1. The result shows that the stronger shear intensity is, the heavier is the MBR been scoured and the smaller is the change of TMP. The best shear intensity was G=60s-1 after considering all factors comprehensively. Finally, the membrane modules were analyzed by scanning electron microscope (SEM). By the SEM pictures we can see that there are some spots on the membrane surface which deposited by fine grains, EPS and SMP. The spots have different size and location, large scale or compact contamination layer can not been found in the pictures. So it indicates that the changing of aeration method and the controlling of shear intensity has a positive impact on slowing down the membrane fouling.

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