Surface water clarification by ultrafiltration with an immersed membrane system: effect of coagulation/aeration on flux enhancement

2003 ◽  
Vol 3 (5-6) ◽  
pp. 393-399 ◽  
Author(s):  
P. Choksuchart ◽  
M. Héran ◽  
A. Grasmick
Keyword(s):  
Ferric Chloride ◽  
Membrane Surface ◽  
Membrane System ◽  
Critical Conditions ◽  
Transmembrane Pressure ◽  
Permeate Flux ◽  
System Effect ◽  
Fiber Network ◽  
Membrane Cleaning ◽  
Concentrated Suspension

A new clarification system was developed to intensify a clarification step by ultrafiltration. Membrane modules equipped with capillary fibers were immersed in a reactor where a horizontal water circulation and a vertical air bubble circulation could assist in minimizing clogging inside the fiber network. Experiments were conducted with a clay particle suspension. Ferric chloride was added to induce coagulation of suspended particles. Results show that when filtering was operated under supracritical conditions clay deposit was observed on the membrane surface and a rapid increase in transmembrane pressure (TMP) value appeared. Air bubbling, and above all adding ferric chloride, allowed an actual enhancement of the filtering conditions. In optimal conditions, a very high concentrated suspension (5.0 g SS/L), filtering evolution was comparable to a clear water filtration until a 65 L/h/m2 permeate flux value (obtained under a 0.16 bar TMP), further a rapid fouling inside the fiber network appeared and obliged us to undertake specific membrane cleaning. The chosen membrane cleaning procedure showed that the particle deposit was the main fouling cause when filtering above the critical conditions.

Influence of aeration and permeate flux on deposition of particulates on membrane surface

2010 ◽  
Vol 10 (6) ◽  
pp. 979-986
Author(s):  
Rupak Aryal ◽  
Saravanamuthu Vigneswaran ◽  
Jaya Kandasamy ◽  
Bivek Baral ◽  
Alain Grasmick
Keyword(s):  
Particle Deposition ◽  
Membrane Surface ◽  
Particle Diameter ◽  
Transmembrane Pressure ◽  
Physical Parameters ◽  
Permeate Flux ◽  
Composite Effect ◽  
Maximum Particle ◽  
The Difference ◽  
Two Parameters

In microfiltration, a deposit of foulant tends to form on the membrane surface and this usually controls the performance of the filtration process. This paper discusses the influence of physical parameters such as aeration and permeates flux on migration and deposition of above micron particles on the membrane surface. Kaolin clay suspension of particle 3.7–8 μm with mean particle diameter 4.1 μm was used in this study. Equal amount of mass of deposited particles on the membrane surface created different transmembrane pressure (TMP) when operated at different aeration rates and permeate flux showing that there is a composite effect. The particle deposition rate at the beginning at lower flux was almost linear which changed to a sharp logarithamic rise at higher flux. The difference in TMP rise for the same amount of deposit demonstrated the selective nature of particle deposition. The mass of the particle deposition on the membrane surface could be described by two parameters: maximum deposition and time using a simple empirical logarithamic equation y=k/[1+exp(b−at)], where k, a, and b are constant; y is the particulate mass deposit (g/m2) and t is the time. The maximum particle mass deposition growth could be described by the equation dy/dt=1/4ka.

Microfiltration of post-fermentation broth with backflushing membrane cleaning

2015 ◽  
Vol 69 (4) ◽  
Author(s):  
Marek Gryta ◽  
Wirginia Tomczak
Keyword(s):  
Filter Cake ◽  
Fermentation Broth ◽  
Reverse Flow ◽  
Membrane Surface ◽  
Permeate Flux ◽  
Membrane Cleaning ◽  
Fermentation Products ◽  
Important Stage ◽  
Short Time

AbstractSeparation of microorganism cells from broth is a very important stage in the recovery of fermentation products. The microfiltration of fermented glycerol solutions was studied. During this process, the filter cake building up on the membrane surface caused an increase of filtration resistances, resulting in the decrease of the permeate flux. In this work, short time reverse flow of permeate was used to remove the fouling layer after each cycle of the filtration. The applied periodical membrane cleaning led to minimization of the observed fouling effects

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.

Application of air backflushing technique in membrane bioreactor

1997 ◽  
Vol 36 (12) ◽  
pp. 259-266 ◽  
Author(s):  
C. Visvanathan ◽  
Byung-Soo Yang ◽  
S. Muttamara ◽  
R. Maythanukhraw
Keyword(s):  
Activated Sludge ◽  
Membrane Bioreactor ◽  
Hollow Fiber Membrane ◽  
Membrane Surface ◽  
Operation Time ◽  
Transmembrane Pressure ◽  
Stable Operation ◽  
Aeration Tank ◽  
Permeate Flux ◽  
Cake Layer

The optimum air backflushing and filtration cycle was investigated for a 0.1 μm hollow fiber membrane module immersed in an activated sludge aeration tank. It was found that 15 minutes filtration and 15 minutes air backflushing gave the best result both in terms of flux stability and net cumulative permeate volume. Although this cyclic operation could not completely remove the clogging, this process improved the flux by up to 371% compared to the continuous operation. During the long term runs, three different hydraulic retention times (HRT) of 12, 6 and 3 hours, corresponding to 0.16, 0.32 and 0.64 m3/m2.d of permeate flux respectively, were investigated. Stable operation was obtained at the HRT of 12 hours. Decrease in HRT led to rapid formation of a compact cake layer on the membrane surface thus increasing the transmembrane pressure. It was also noted that filtration pressure increases with increase in bioreactor MLSS concentration. With operation time, the MLVSS/MLSS value decreased without significant effect on the process performance, indicating that inorganic mass constantly accumulated in the bioreactor. All the experimental runs produced more than 90% removal of COD, and TKN. In terms of physical, chemical, biological and bacteriological parameters, the membrane bioreactor effluent was superior to the conventional activated sludge process.

Preparation and Characterization of PVDF-TiO2 Composite Membranes Blended with Different Mw of PVP for Oily Wastewater Treatment using Submerged Membrane System

2014 ◽  
Vol 69 (9) ◽  
Author(s):  
C. S. Ong ◽  
W. J. Lau ◽  
P. S. Goh ◽  
A. F. Ismail Ismail
Keyword(s):  
Polyvinylidene Fluoride ◽  
Membrane Surface ◽  
Pure Water ◽  
Water Flux ◽  
Composite Membranes ◽  
Membrane System ◽  
Morphological Properties ◽  
Oily Wastewater ◽  
Permeate Flux ◽  
Oily Wastewater Treatment

Polyvinylidene fluoride (PVDF) hollow fiber ultrafiltration (UF) membranes consisted of TiO2 and different molecular weight (Mw) of polyvinylpyrrolidone (PVP) (i.e. 10, 24, 40 and 360 kDa) were prepared to treat synthesized oily wastewater. The membrane performances were characterized in terms of pure water flux, permeate flux and oil rejection while the membrane morphological properties were studied using SEM and AFM. PVDF-TiO2 composite membrane prepared from PVP40k was found as the optimum membrane due to its high flux and high rejection during filtration process, recording      45 L/m2.h and 80% respectively, when tested using 250 ppm oily solution under submerged condition. The experimental results demonstrated that with increasing Mw of PVP, PVDF-TiO2 membrane had higher protein rejection, smaller porosity and smoother surface layer. With increasing oil concentration from 250 to 1000 ppm, the permeate flux of the PVDF-PVP40k was obviously decreased while the oil rejection was gradually increased due to the additional selective layer formed on the membrane surface.  Based on the findings, the PVDF-TiO2 membrane with PVP40k can be considered as a potential membrane for oily wastewater industry due to the high permeate flux and oil rejection. 

scholarly journals Optimizing the operational conditions of a membrane bioreactor used for domestic wastewater treatment

2005 ◽  
Vol 48 (spe) ◽  
pp. 119-126 ◽  
Author(s):  
Priscilla Zuconi Viana ◽  
Ronaldo Nobrega ◽  
Eduardo Pacheco Jordão ◽  
José Paulo Soares de Azevedo
Keyword(s):  
Municipal Wastewater ◽  
Membrane Surface ◽  
Domestic Wastewater ◽  
Transmembrane Pressure ◽  
Permeate Flux ◽  
Operational Parameters ◽  
Operational Conditions ◽  
Air Supply ◽  
Aeration System ◽  
Domestic Wastewater Treatment

This study evaluated the performance of a sidestream membrane module combined with an aeration system for the treatment of municipal wastewater. To investigate the membrane's behavior and to control fouling, trials in laboratory units were conducted. In these tests, optimal values were established for some operational parameters, such as crossflow velocity, transmembrane pressure and air supply to continuously flush the membrane surface. Air supply improved the behavior of the permeate flux over time. After six hours operation, the stabilized flux was 35 L/m².h at a total pressure of 0.40 bar (wastewater pressure of 0.05 bar and air pressure of 0.35 bar) and Reynolds Number of 4,600. All permeate samples analyzed indicated absence of fecal coliform and Escherichia coli.

scholarly journals THE EFFECT OF OPERATING CONDITIONS ON CRITICAL FLUX AND REVERSIBLE FOULING IN MEMBRANE FILTRATION USING GAS SPARGING TECHNIQUE

2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Harunsyah Harunsyah ◽  
Nik Meriam Sulaiman
Keyword(s):  
Flow Rate ◽  
Membrane Filtration ◽  
Membrane System ◽  
Operating Conditions ◽  
Transmembrane Pressure ◽  
Feed Flow Rate ◽  
Permeate Flux ◽  
Critical Flux ◽  
Gas Sparging ◽  
Cake Layer

Gas sparging method utilizing injection of nitrogen gas was employed during the ultrafiltration of the natural rubber effluent (latex serum). The objective of this research was to investigate the effect of gas sparging on the critical flux and the observed reversible cake layer resistance during the ultrafiltration of skim latex serum. Experiments were conducted using a 100 kDa MWCO tubular membrane (PCI Membrane System) mounted vertically. The effect of operating parameters, such as feed flow rate, concentration and transmembrane pressure were investigated. The results showed that when the feed flow rate was increased, the permeate was correspondingly increased and the reversible cake resistance decreased. In this research a feed flow rate of 1400 ml/min and transmembrane pressure of 13.00 psig resulted in the maximum total permeate flux of 70.80 L/m2h. Results from this study obtained so far showed that the use of gas sparging has been able to increase total permeate flux between 8.3% and 145.3% compared to non-gas sparged condition. Critical flux occurrence was increased to 82.63% above the value obtained for non-sparged condition and applied transmembrane pressure can be reduced to 2.4% of the non-gas sparged condition.Keyword: skim latex serum, reversible fouling, gas sparged, critical flux

scholarly journals Tanning Wastewater Treatment by Ultrafiltration: Process Efficiency and Fouling Behavior

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 461
Author(s):  
Fu Yang ◽  
Zhengkun Huang ◽  
Jun Huang ◽  
Chongde Wu ◽  
Rongqing Zhou ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Shear Rate ◽  
Membrane Surface ◽  
Filtration Efficiency ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Transmembrane Pressure ◽  
Leather Industry ◽  
Pore Blocking ◽  
The Impact

Ultrafiltration is a promising, environment-friendly alternative to the current physicochemical-based tannery wastewater treatment. In this work, ultrafiltration was employed to treat the tanning wastewater as an upstream process of the Zero Liquid Discharge (ZLD) system in the leather industry. The filtration efficiency and fouling behaviors were analyzed to assess the impact of membrane material and operating conditions (shear rate on the membrane surface and transmembrane pressure). The models of resistance-in-series, fouling propensity, and pore blocking were used to provide a comprehensive analysis of such a process. The results show that the process efficiency is strongly dependent on the operating conditions, while the membranes of either PES or PVDF showed similar filtration performance and fouling behavior. Reversible resistance was the main obstacle for such process. Cake formation was the main pore blocking mechanism during such process, which was independent on the operating conditions and membrane materials. The increase in shear rate significantly increased the steady-state permeation flux, thus, the filtration efficiency was improved, which resulted from both the reduction in reversible resistance and the slow-down of fouling layer accumulate rate. This is the first time that the fouling behaviors of tanning wastewater ultrafiltration were comprehensively evaluated, thus providing crucial guidance for further scientific investigation and industrial application.

scholarly journals Pilot Study on the Combination of Different Pre-Treatments with Nanofiltration for Efficiently Restraining Membrane Fouling While Providing High-Quality Drinking Water

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 380
Author(s):  
Yan Chen ◽  
Huiping Li ◽  
Weihai Pang ◽  
Baiqin Zhou ◽  
Tian Li ◽  
...  
Keyword(s):  
Drinking Water ◽  
Activated Carbon ◽  
Membrane Fouling ◽  
Membrane Surface ◽  
Post Treatment ◽  
Size Exclusion ◽  
Transmembrane Pressure ◽  
Feed Water ◽  
High Quality ◽  
Treated Water

Nanofiltration (NF) is a promising post-treatment technology for providing high-quality drinking water. However, membrane fouling remains a challenge to long-term NF in providing high-quality drinking water. Herein, we found that coupling pre-treatments (sand filtration (SF) and ozone–biological activated carbon (O3-BAC)) and NF is a potent tactic against membrane fouling while achieving high-quality drinking water. The pilot results showed that using SF+O3-BAC pre-treated water as the feed water resulted in a lower but a slowly rising transmembrane pressure (TMP) in NF post-treatment, whereas an opposite observation was found when using SF pre-treated water as the feed water. High-performance size-exclusion chromatography (HPSEC) and three-dimensional excitation–emission matrix (3D-EEM) fluorescence spectroscopy determined that the O3-BAC process changed the characteristic of dissolved organic matter (DOM), probably by removing the DOM of lower apparent molecular weight (LMW) and decreasing the biodegradability of water. Moreover, amino acids and tyrosine-like substances which were significantly related to medium and small molecule organics were found as the key foulants to membrane fouling. In addition, the accumulation of powdered activated carbon in O3-BAC pre-treated water on the membrane surface could be the key reason protecting the NF membrane from fouling.

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