Description of different effects of in-line coagulation upon semi-dead-end ultrafiltration

2003 ◽  
Vol 3 (5-6) ◽  
pp. 337-344 ◽  
Author(s):  
W. Doyen ◽  
R. Vandaele ◽  
B. Molenberghs ◽  
J. Cromphout ◽  
P. Bielen ◽  
...  
Keyword(s):  
Surface Water ◽  
Membrane Surface ◽  
Environmental Scanning Electron Microscopy ◽  
High Volume ◽  
High Water ◽  
Transmembrane Pressure ◽  
Water Recovery ◽  
Dead End ◽  
Cake Layer ◽  
Cake Porosity

This paper describes the results of research focussed on the different effects of in-line coagulation (FeCl3), towards the operation of semi-dead-end UF for drinking water and process water production starting from surface water. In this research, firstly the effects of the use of FeCl3 on the formed cake were studied, by both direct and indirect measurements. Using the ESEM technique (environmental scanning electron microscopy), which enables one to make pictures of wet samples, we observed that cake thickness was much higher upon use of FeCl3 (20 instead of 2 μm). As a result, the cake porosity was calculated to be much higher with than without coagulant use (93% instead of 37%). From the stability (nonincreasing) of the starting transmembrane pressure (TMP) in the successive filtration cycles, upon semidead-end operation, it was concluded that cake layer was less prone to adhere to the membrane surface when using coagulant. This is even more emphasized once the dosing is stopped, as a consequence the TMP rises very steeply under difficult circumstances, such as; high flux rates, high water recovery rates, and the use of membranes made from polymers with high adsorption properties. Secondly, indirect effects of the use of coagulant on filtration behaviour were investigated. Thus, it was found that TMP increase in the filtration cycle was much lower, due to depth filtration in the formed high-volume cake, and TMP was much more stable over a long time. These observations were in good agreement with found higher cake porosity. Moreover, it was observed that due to the use of a coagulant, the influences of membrane polymer nature and membrane structure disappeared, cleaning action could be postponed and cleaning aggressiveness could be lowered. In addition, water recovery and flux rate could be increased, and influence of seasonal water quality variations could be better faced. Finally, it was found that the treatment of surface water with high DOC content (e.g. 10 mg DOC/l) was enabled.

scholarly journals Ozone Chemically Enhanced Backwash for Ceramic Membrane Fouling Control in Cyanobacteria-Laden Water

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 213
Author(s):  
Stéphane Venne ◽  
Onita D. Basu ◽  
Benoit Barbeau
Keyword(s):  
Surface Water ◽  
Surface Waters ◽  
Membrane Fouling ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Operating Costs ◽  
Fouling Control ◽  
Dead End ◽  
Cake Layer ◽  
Flow Experiments

Membrane fouling in surface waters impacted by cyanobacteria is currently poorly controlled and results in high operating costs. A chemically enhanced backwash (CEB) is one possible strategy to mitigate cyanobacteria fouling. This research investigates the potential of using an ozone CEB to control the fouling caused by Microcystis aeruginosa in filtered surface water on a ceramic ultrafiltration membrane. Batch ozonation tests and dead-end, continuous flow experiments were conducted with ozone doses between 0 and 19 mg O3/mg carbon. In all tests, the ozone was shown to react more rapidly with the filtered surface water foulants than with cyanobacteria. In addition, the ozone CEB demonstrated an improved mitigation of irreversible fouling over 2 cycles versus a single CEB cycle; indicating that the ozone CEB functioned better as the cake layer developed. Ozone likely weakens the compressible cake layer formed by cyanobacteria on the membrane surface during filtration, which then becomes more hydraulically reversible. In fact, the ozone CEB reduced the fouling resistance by 35% more than the hydraulic backwash when the cake was more compressed.

scholarly journals Numerical simulation of filtration performance in submerged membrane bioreactors: effect of particle packed structure

2017 ◽  
Vol 76 (9) ◽  
pp. 2503-2514 ◽  
Author(s):  
Zhidong Wang ◽  
Kuizu Su ◽  
Tong Shu ◽  
Weihong Wang
Keyword(s):  
Membrane Surface ◽  
Membrane Bioreactors ◽  
Navier Stokes ◽  
Permeate Flux ◽  
The Finite Element Method ◽  
Brinkman Equations ◽  
Filtration Performance ◽  
Cake Layer ◽  
Packed Structure ◽  
Cake Porosity

Abstract It is widely known that the accumulation of solid matter forming a cake layer on the membrane surface is one of the major limitations of the filtration performance in submerged membrane bioreactors (SMBR). This study is focused on the influence of the cake porosity of different particle microscopic packed structures on the filtration performance of hollow fiber systems. An integrated model based on the finite element method to simulate numerically the flow in an SMBR is presented. The model coupled the Navier–Stokes and Darcy Brinkman equations to simulate a complete filtration run. The cake growth took into consideration not only the deposition with local filtration velocity but also the effect of aeration scouring. A novel solution of mesh deformation was adopted to investigate transient cake growth along the fiber. Comparisons between simulations and experiments are in good agreement. The results show that a higher porosity particle packed structure causes non-uniform filtration and cake thickness but also higher permeate flux. Meanwhile, the proportion of cake resistance to total resistance increases with the decrease of porosity.

scholarly journals Fouling Mechanisms Analysis via Combined Fouling Models for Surface Water Ultrafiltration Process

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 149 ◽  
Author(s):  
Bin Huang ◽  
Hangkun Gu ◽  
Kang Xiao ◽  
Fangshu Qu ◽  
Huarong Yu ◽  
...  
Keyword(s):  
Water Treatment ◽  
Surface Water ◽  
Membrane Fouling ◽  
Mechanism Analysis ◽  
Surface Water Treatment ◽  
Dead End ◽  
Cake Layer ◽  
Significant Difference ◽  
Combined Models ◽  
And Control

Membrane fouling is still the bottleneck affecting the technical and economic performance of the ultrafiltration (UF) process for the surface water treatment. It is very important to accurately understand fouling mechanisms to effectively prevent and control UF fouling. The rejection performance and fouling mechanisms of the UF membrane for raw and coagulated surface water treatment were investigated under the cycle operation of constant-pressure dead-end filtration and backwash. There was no significant difference in the UF permeate quality of raw and coagulated surface water. Coagulation mainly removed substances causing turbidity in raw surface water (including most suspended particles and a few organic colloids) and thus mitigated UF fouling effectively. Backwash showed limited fouling removal. For the UF process of both raw and coagulated surface water, the fittings using single models showed good linearity for multiple models mainly due to statistical illusions, while the fittings using combined models showed that only the combined complete blocking and cake layer model fitted well. The quantitative calculations showed that complete blocking was the main reason causing flux decline. Membrane fouling mechanism analysis based on combined models could provide theoretical supports to prevent and control UF fouling for surface water treatment.

scholarly journals Performance Evaluation of Polymeric Membrane Permeability Characteristics Using Different Aqueous Solutions

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Erhan Mustafa ◽  
Katerina Atkovska ◽  
Stefan Kuvendziev ◽  
Mirko Marinkovski ◽  
Kiril Lisichkov
Keyword(s):  
Wastewater Treatment ◽  
Aqueous Solutions ◽  
Membrane Permeability ◽  
Membrane Filtration ◽  
Membrane Surface ◽  
Process Efficiency ◽  
Polymeric Membrane ◽  
Transmembrane Pressure ◽  
Permeability Characteristics ◽  
Dead End

In the last decade the application of membrane separation technology is more increasing. The membrane in water purification and wastewater treatment is essential separation process used for water reclamation. The production of new membrane types with different permeable characteristics and performances allows them to be fitted in different membrane modules that can be used in the membrane filtration. The water characteristics are important for the membrane performance. It can seriously affect the permeability characteristics and increase the fouling on the membrane surface. In wastewater treatment, the characteristics of the aqueous influent can reduce the permeability of the membrane and the process efficiency of the membrane bioreactor (MBR). The aim of this paper is to explore the effect of different aqueous solutions on membrane permeability using dead end filtration process. For this purpose, NaCl solution with different concentration were prepared and the effect of the concentration polarization on the membrane was observed. The constructed membrane module was also tested with real water sample and the membrane permeability was analyzed. In this experiment a polymeric membrane produced from polyether sulphonate (PES), with diameter of 5.0 cm and pore size of 0.04 µm was assembled in a constructed module for dead-end filtration. The module was constructed in a way that would allow turbulence of the solution on the membrane surface. The following working parameters were examined: transmembrane pressure (TMP), the types of solutions, the working temperature, and the influence of agitation on the feeding to the specific membrane flux and permeability. The results showed that the membrane permeability is affected by the water organic and inorganic constituents and in the process of design of membrane reactor for wastewater treatment, the water composition should be taken in consideration.

scholarly journals Effect and mechanism of reduced membrane bioreactor fouling by powdered activated carbon

2021 ◽  
Vol 83 (5) ◽  
pp. 1005-1016
Author(s):  
Yongji Zhang ◽  
Xiaotong Wang ◽  
Hexiu Ye ◽  
Lingling Zhou ◽  
Zhiling Zhao
Keyword(s):  
Activated Carbon ◽  
Membrane Fouling ◽  
Positive Impact ◽  
Membrane Surface ◽  
Polluted Water ◽  
Transmembrane Pressure ◽  
Carbon Membrane ◽  
Cake Layer ◽  
Cleaning Methods ◽  
Alkaline Cleaning

Abstract Powered Activated Carbon – Membrane Bioreactors (PAC-MBRs) have been used with good results for slightly polluted water treatment. Our batch experiments showed that the transmembrane pressure of a PAC-MBR was 25% less than that of a MBR in one period of test, which indicated that PAC did help control the fouling in MBRs. Based on this observation, several mechanisms of membrane fouling of MBRs and PAC-MBRs were investigated to have some insight into how PAC brought a positive impact. The total resistances decreased by 60% and different resistances were redistributed after adding PAC. The dominant one changed from filtration resistance to cake resistance. These smaller cake resistances resulted from the PAC because, showing in the scanning electron microscopy pictures, it made the cake layer looser and rougher than that on a normal membrane. Meanwhile, the analysis of the membrane eluent showed that the addition of PAC changed the microbial species and its metabolites on the membrane and effectively reduced the adsorption of hydrophilic organic molecules on the membrane surface. Additionally, PAC prevented polypeptide compounds from being trapped inside the pores of membranes, so the cake on the PAC-MBR contaminated membrane surface was easier to scrape off. In the test of cleaning methods, alkaline cleaning removed the most organics from contaminated membranes to restore membrane performance.

Behavior of micro-particles in monolith ceramic membrane filtration with pre-coagulation

2004 ◽  
Vol 50 (12) ◽  
pp. 317-325 ◽  
Author(s):  
H. Yonekawa ◽  
Y. Tomita ◽  
Y. Watanabe
Keyword(s):  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Flow Analysis ◽  
Ceramic Membranes ◽  
End Point ◽  
Micro Particles ◽  
Dead End ◽  
Cake Layer ◽  
The Dead

This paper is intended to clarify the characteristics unique to monolith ceramic membranes with pre-coagulation by referring to the behavior of micro-particles. Flow analysis and experiments have proved that monolith ceramic membranes show a unique flow pattern in the channels within the element, causing extremely rapid flocculation in the channel during dead-end filtration. It was assumed that charge-neutralized micro-particles concentrated near the membrane surface grow in size due to flocculation, and as a result, coarse micro-particles were taken up by the shearing force to flow out. As the dead end points of flow in all the channels are located near the end of the channels with higher filterability, most of the flocculated coarse particles are formed to a columnar cake intensively at the dead end point. Therefore cake layer forming on the membrane other than around the dead end point is alleviated. This behavior of particle flocculation and cake formation at the dead end point within the channels are unique characteristics of monolith ceramic membranes. This is why all monolith ceramic membrane water purification systems operating in Japan do not have pretreatment equipment for flocculation and sedimentation.

scholarly journals Studies of polypropylene membrane fouling during microfiltration of broth with Citrobacter freundii bacteria

2015 ◽  
Vol 17 (4) ◽  
pp. 56-64 ◽  
Author(s):  
Marek Gryta ◽  
Marta Waszak ◽  
Maria Tomaszewska
Keyword(s):  
Membrane Fouling ◽  
Membrane Surface ◽  
Transmembrane Pressure ◽  
Citrobacter Freundii ◽  
Permeate Flux ◽  
Process Duration ◽  
Polypropylene Membrane ◽  
Flux Decline ◽  
Cake Layer ◽  
Scanning Electron

Abstract In this work a fouling study of polypropylene membranes used for microfiltration of glycerol solutions fermented by Citrobacter freundii bacteria was presented. The permeate free of C. freundii bacteria and having a turbidity in the range of 0.72–1.46 NTU was obtained. However, the initial permeate flux (100–110 L/m2h at 30 kPa of transmembrane pressure) was decreased 3–5 fold during 2–3 h of process duration. The performed scanning electron microscope observations confirmed that the filtered bacteria and suspensions present in the broth formed a cake layer on the membrane surface. A method of periodical module rinsing was used for restriction of the fouling influence on a flux decline. Rinsing with water removed most of the bacteria from the membrane surface, but did not permit to restore the initial permeate flux. It was confirmed that the irreversible fouling was dominated during broth filtration. The formed deposit was removed using a 1 wt% solution of sodium hydroxide as a rinsing solution.

scholarly journals Effect of operation paramaters on the filtration behavior in microfiltratration of TiO2 suspended

2021 ◽  
Vol 10 (1) ◽  
pp. 84-92
Author(s):  
Chinh Pham Duc ◽  
Thuy Nguyen Thi Thu ◽  
Tham Bui Thi ◽  
Quang Phan Ngoc ◽  
Cuong Pham Manh ◽  
...  
Keyword(s):  
Ph Value ◽  
Complete System ◽  
Membrane Surface ◽  
Experimental System ◽  
Transmembrane Pressure ◽  
Permeate Flux ◽  
Cake Layer ◽  
Mechanical Separation ◽  
Set Up ◽  
The Relationship

The photocatalytic reaction using TiO2 suspended to degrade the residues of toxic organic compounds has been extensively studied, but the ultilization of this process has not been recorded on an industrial scale. One of the primary reasons is the separation of TiO2 catalyst from the treated solution mixture. Conventional mechanical separation methods such as centrifugation, flocculation-deposition do not allow for thorough separation and catalytic reuse, whereas the microfiltration / ultrafiltration membrane process has been demonstrated to be capable of composting isolates very suspended particles. Accordingly, in this study, an experimental system separating TiO2-P25 suspension by microfiltration membrane 0.2 µm on laboratory scale was set up. Effects of operating factors: TiO2 concentration, pH value, transmembrane pressure and crosss flow velocity were investigated. Result shown that TiO2 concentration greater than 1 g / l will fundamentally diminish the permeate flux, futhermore, in the transmembrane  pressure differential (∆P) fluctuating from 0.3 to 1.2 bar, the relationship between J and ∆P is a linear relationship. In addition, the study likewise shown that the formation of the cake layer (scale) on the membrane surface is the fundamental driver of the permeate flux degradation over time. These results are the basis for integrating membrane and photocatalytic processes into a complete system for degradation toxic organic compound residues.

scholarly journals Low-Vacuum Filtration as an Alternative Extracellular Vesicle Concentration Method: A Comparison with Ultracentrifugation and Differential Centrifugation

Pharmaceutics ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 872
Author(s):  
Anna Drożdż ◽  
Agnieszka Kamińska ◽  
Magdalena Surman ◽  
Agnieszka Gonet-Surówka ◽  
Robert Jach ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Culture Media ◽  
Membrane Surface ◽  
Environmental Scanning Electron Microscopy ◽  
High Volume ◽  
Drug Carriers ◽  
Attenuated Total Reflection ◽  
Differential Centrifugation ◽  
Isolation Method ◽  
Vacuum Filtration

Recent years have brought great focus on the development of drug delivery systems based on extracellular vesicles (EVs). Considering the possible applications of EVs as drug carriers, the isolation process is a crucial step. To solve the problems involved in EV isolation, we developed and validated a new EV isolation method—low-vacuum filtration (LVF)—and compared it with two commonly applied procedures—differential centrifugation (DC) and ultracentrifugation (UC). EVs isolated from endothelial cell culture media were characterized by (a) Transmission Electron Microscopy (TEM), (b) Nanoparticle Tracking Analysis (NTA), (c) Western blot and (d) Attenuated Total Reflection Fourier-Transform Infrared Spectroscopy (ATR-FTIR). Additionally, the membrane surface was imaged with Environmental Scanning Electron Microscopy (ESEM). We found that LVF was a reproducible and efficient method for EV isolation from conditioned media. Additionally, we observed a correlation between ATR-FTIR spectra quality and EV and protein concentration. ESEM imaging confirmed that the actual pore diameter was close to the values calculated theoretically. LVF is an easy, fast and inexpensive EV isolation method that allows for the isolation of both ectosomes and exosomes from high-volume sources with good repeatability. We believe that it could be an efficient alternative to commonly applied methods.

scholarly journals Ingredient-Wise Study of Flux Characteristics in the Ceramic Membrane Filtration of Uncontaminated Synthetic Metalworking Fluids, Part 2: Analysis of Underlying Mechanisms

1999 ◽  
Vol 122 (4) ◽  
pp. 746-752 ◽  
Author(s):  
Steven J. Skerlos ◽  
N. Rajagopalan ◽  
Richard E. DeVor ◽  
Shiv G. Kapoor ◽  
V. Don Angspatt
Keyword(s):  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Membrane Surface ◽  
Environmental Scanning Electron Microscopy ◽  
Lubricant Additive ◽  
Metalworking Fluids ◽  
Environmental Scanning ◽  
Flux Decline ◽  
Cake Layer ◽  
Underlying Mechanisms

Part 2 of this paper reveals the predominant mechanism of flux decline during microfiltration of the synthetic MWF described in Part 1 of this paper. An analysis of flux data obtained during the experimental investigation suggests that adsorptive interactions occur at the membrane surface. Field Emission Environmental Scanning Electron Microscopy (FE-ESEM) images of aluminum oxide membranes after MWF microfiltration illustrate that adsorption leads to a reduction in pore diameter that serves to reduce flux. The majority of the adsorption is accounted for by a single lubricant additive in the MWF formulation. FE-ESEM images also reveal that the mechanism of flux decline for the defoamer varies depending on the presence of lubricant additive in solution. In the absence of lubricant additive, the defoamer forms a cake layer at the membrane surface. In the presence of the lubricant additive, the defoamer adsorbs to the surface of the membrane with the lubricant additive to constrict pores. In contrast to the lubricant additive and defoamer, base fluid flux decline observed after specialty additive exposure cannot be accounted for by adsorption leading to pore constriction. [S1087-1357(00)01203-X]

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