scholarly journals Critical flux investigation in treating o/w emulsion by TiO2/Al2O3-PVDF UF membrane

2017 ◽  
Vol 76 (10) ◽  
pp. 2785-2792 ◽  
Author(s):  
Xuesong Yi ◽  
Yong Wang ◽  
Limei Jin ◽  
Wenxin Shi
Keyword(s):  
Membrane Fouling ◽  
High Efficiency ◽  
Pure Water ◽  
Membrane System ◽  
Transmembrane Pressure ◽  
Step Method ◽  
Critical Flux ◽  
Zero Rate ◽  
Long Time

Abstract A standard transmembrane pressure (TMP) step method has been used in membrane fouling assessment in tube ultrafiltration (UF) membrane system treating oil water (o/w) emulsion operated at constant TMP. Three flux reduction curve with different o/w concentration based on TMP variation were concluded by experiment, then, to describe fouling behavior and identify the occurrence of fouling in the so-called critical flux. Furthermore, sub-critical and super-critical flux experiment with a long time was determined, and zero rate of flux reduction (dF/dt) was never found during the whole trial period, indicating that critical flux in o/w UF process with its strict definition could not be defined in this paper. However, quasi-critical flux exists, under which the pollution rate was very slow. Moreover, a high-efficiency four steps cleaning method: mechanic scraping, pure water wash, pure water reverse wash, and dosing cleaning, was explored. It concluded that critical flux in real o/w UF system determined by TMP-step method can be used to predict long-term critical behavior with useful data on fouling propensity.

Improvement of microfiltration performance in water treatment: is critical flux a viable solution?

2000 ◽  
Vol 41 (10-11) ◽  
pp. 309-315 ◽  
Author(s):  
S. Vigneswaran ◽  
D.Y. Kwon ◽  
H.H. Ngo ◽  
J.Y. Hu
Keyword(s):  
Membrane Fouling ◽  
Particle Deposition ◽  
Material Balance ◽  
Transmembrane Pressure ◽  
Operational Mode ◽  
Permeate Flux ◽  
Critical Flux ◽  
Viable Solution ◽  
Crossflow Microfiltration

In this study, three definitions for critical flux were introduced based on the crossflow microfiltration (CFMF) experiments conducted under an operational mode of constant permeate flux. The critical flux based on material balance was calculated from the rate of particles deposition. The highest permeate flux results in no particle deposition being taken at the critical flux. The second definition was based on the increase in transmembrane pressure (TMP). The critical flux based on the TMP increase is the flux below which the membrane fouling does not occur. The third definition was based on the direct observation of particles deposition through microscope. Detailed experiments were conducted with synthetic suspension of different sizes of latex particles. Long term experiments conducted with polydispersed kaolin clay suspension indicated that the critical flux based on material balance concept is more realistic in field conditions.

scholarly journals Effect of applied voltage on membrane fouling in the amplifying anaerobic electrochemical membrane bioreactor for long-term operation

RSC Advances ◽  
2021 ◽  
Vol 11 (50) ◽  
pp. 31364-31372
Author(s):  
Mengjing Cao ◽  
Yongxiang Zhang ◽  
Yan Zhang
Keyword(s):  
Chemical Oxygen Demand ◽  
Applied Voltage ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Glucose Solution ◽  
Oxygen Demand ◽  
Term Operation ◽  
Long Time

A novel and amplifying anaerobic electrochemical membrane bioreactor was constructed and operated for a long time (204 days) with synthetic glucose solution having an average chemical oxygen demand (COD) of 315 mg L−1, at different applied voltages and room temperatures.

Sustainable membrane operation design for the treatment of the synthetic coke wastewater in SMBR

2009 ◽  
Vol 60 (8) ◽  
pp. 2115-2124 ◽  
Author(s):  
Ying Zhou ◽  
Zhen-liang Xu ◽  
Shahda Munib ◽  
Gui-e Chen ◽  
Qiong Lu
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Operating Time ◽  
Term Treatment ◽  
Membrane Properties ◽  
Critical Flux ◽  
Coke Wastewater ◽  
Sustainable Operation ◽  
Long Term Treatment

Membrane fouling in the membrane bioreactor (MBR) is typically caused by the interaction of microbial characteristics, hydrodynamic behavior, operation environment, wastewater characteristics and membrane properties, which result in the deterioration of performance and increasing energy consumption and cost of membrane replacement. The effect of the crucial MBR parameters (the microbial loading and characteristics, dissolved oxygen (DO), hydraulic retention time (HRT), backwashing conditions and membrane characteristics) on membrane fouling was investigated in a submerged membrane bioreactor (SMBR) during the long term treatment of synthetic coke wastewater. Also the optimum operation strategies were further utilized in order to satisfy the minimal membrane fouling operation through a long-term evaluation of the MBR performance. It has been demonstrated that with application of these optimal designed conditions, significant membrane fouling improvements were achieved over a long operating time, so it was possible to perform in sustainable operation for MBR. In this study, the upper limit of the sustainable flux is found to be as much as 18.6 L/m2 h and the optimum sustainable flux value should be 50 ∼ 75% of critical flux to satisfy the desired sustainable operation period.

Influence of the Dissolution Laws of N, P on the Activated Sludge by Ozone Oxidation

2013 ◽  
Vol 295-298 ◽  
pp. 1215-1221
Author(s):  
Rong Wang ◽  
Ai Ping Tang
Keyword(s):  
Activated Sludge ◽  
Total Phosphorus ◽  
High Efficiency ◽  
Ammonia Nitrogen ◽  
Nitrogen And Phosphorus ◽  
Removal Rates ◽  
Ozone Oxidation ◽  
Conventional Activated Sludge ◽  
Long Time

The high sludge production has becoming one of the main drawbacks in the conventional activated sludge process. The ozone oxidation is considered as one of the most effective techniques owing to its high efficiency and non-secondary pollution. In this paper, the solubilization rules of nitrogen and phosphorus with directing injection ozone in a static unit were studied, then, the long-term removal rates of ammonia nitrogen and total phosphorus in SBR system of directing injection ozone were studied with ozone dosage from 0.01～0.04gO3/gSS. The results of static experiments showed that the nitrate concentration increased quickly from 3.52mg/L to 13.83mg/L, the concentration of organic nitrogen and ammonia increased slightly, whereas, the nitrite concentration decreased gradually at the ozone dosage of 0～0.15gO3/gSS, most of the nitrogen released from the ozonated sludge were escaped from the supernate in the form of nitrogen and ammonia. The result of long-time experiment in SBR system showed that the removal rates of ammonia and total phosphorus was 91.1%, 80.5%, respectively.

scholarly journals Identification of fouling mechanisms in MBRs at constant flowrate: model applications and SEM-EDX characterizations

2017 ◽  
Vol 77 (1) ◽  
pp. 229-238 ◽  
Author(s):  
Bo Hu ◽  
Xingtao Zuo ◽  
Juan Xiong ◽  
Huimeng Yang ◽  
Menghua Cao ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactors ◽  
Transmembrane Pressure ◽  
X Ray ◽  
Inorganic Matter ◽  
Fundamental Understanding ◽  
Combined Models ◽  
Standard Models ◽  
Good Agreement

Abstract A fundamental understanding of fouling mechanisms is critical to improving filtration operations. The performance of four parallel membrane bioreactors (MBRs) with different sludge retention times (SRTs) was monitored during long-term constant flowrate filtration. The characteristics of the membrane and transmembrane pressure (TMP) profiles obtained were studied to demonstrate fouling mechanisms. Both classical blocking models and their combined models were evaluated. The intermediate model provided very good agreement with all the TMP data. However, the combined cake-intermediate and intermediate-standard models were more effective in the description of the experimental data. Contributions analysis indicated that the cake, intermediate and standard blocking models were the dominant fouling mechanisms. Scanning electron microscopy and energy dispersive X-ray (SEM-EDX) imaging showed that cake blocking by organic matter and standard blocking by inorganic matter made the main contributions to membrane fouling. The combined cake-intermediate and intermediate-standard models may be applicable to systems where these two models are consistent with the experimentally observed fouling mechanisms in an MBR.

The Relationship between Critical Flux and Membrane Fouling

2014 ◽  
Vol 535 ◽  
pp. 675-678
Author(s):  
Wei Ying Li ◽  
Jun Peng Zhang ◽  
Wen Ming Li
Keyword(s):  
Membrane Fouling ◽  
Sand Filtration ◽  
Short Term ◽  
Step Method ◽  
Critical Flux ◽  
Surface Features ◽  
On Line ◽  
The Relationship

The critical flux was chosen to show surface features of the membrane fouling and it was determined by the flux-step method. The critical flux of on-line coagulation-UF, sedimentation-UF and sand filtration-UF was investigated and its value was 86.5 L/m2h80.5L/m2h and 68.1L/m2h, respectively. At the same time, the increasing rate of TMP were always lower than the corresponding values measured for the short-term flux-step experiments.

The Effect of Temperature on Performance of Powder Activated Carbon-I Membrane Biological Reactor (PAC-IMBR)

2012 ◽  
Vol 531-532 ◽  
pp. 368-372
Author(s):  
Xing Guan Ma ◽  
Wen Juan Ji ◽  
Jun Ping Sun ◽  
Xiang Xin Xue ◽  
He Yang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Membrane Fouling ◽  
Oxygen Demand ◽  
Effect Of Temperature ◽  
Transmembrane Pressure ◽  
Marked Influence ◽  
Long Time ◽  
Northern Winter ◽  
Powder Activated Carbon ◽  
Effects Of Temperature

Under the unique long-time low temperature conditions (average 8°C) of the northern winter in China, the effects of temperature on water quality and the performance of Powder activated carbon-I Membrane biological reactor (PAC-IMBR) were studied and demonstrated quantitatively by the NH4+-N value, chemical oxygen demand (CODCr) and transmembrane pressure (TMP). The results showed that the supernatant NH4+-N decrease from 1.20 mg·L-1 to 0.81 mg·L-1 with the temperature rising from 8°C to 20°C, while 30.8 mg·L-1 to 23.1 mg·L-1 for the CODCr. However, the temperature rising have no marked influence on the effluent NH4+-N and CODCr due to the filtration of membrane. TMP was measured to characterize membrane fouling and it is clear that the TMP and its increasing rate descend with the temperature rising, which demonstrates that the raising temperature is advantageous to prolong the cycle of PAC-IMRB and alleviate the membrane fouling.

Impact of transmembrane pressure (TMP) on membrane fouling in microalgae harvesting with a uniform shearing vibration membrane system

2018 ◽  
Vol 35 ◽  
pp. 613-623 ◽  
Author(s):  
Shuhong Jiang ◽  
Yalei Zhang ◽  
Fangchao Zhao ◽  
Zhenjiang Yu ◽  
Xuefei Zhou ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Membrane System ◽  
Transmembrane Pressure ◽  
Microalgae Harvesting

The relationship between critical flux and fibre movement induced by bubbling in a submerged hollow fibre system

2005 ◽  
Vol 51 (6-7) ◽  
pp. 115-122 ◽  
Author(s):  
F. Wicaksana ◽  
A.G. Fan ◽  
V. Chen
Keyword(s):  
Membrane Fouling ◽  
Hollow Fibre ◽  
Transmembrane Pressure ◽  
Feed Concentration ◽  
Critical Flux ◽  
Improved Performance ◽  
Qualitative Relationship ◽  
The Relationship ◽  
Mechanical Movement ◽  
Fibre Characteristics

Bubbling has been used to enhance various processes. In this paper we deal with the effect of bubbling on submerged hollow fibre membranes, where bubbling is applied to prevent severe membrane fouling. Previous work with submerged hollow fibres has observed that significant fibre movement can be induced by bubbling and that there is a qualitative relationship between fibre movement and filtration performance. Therefore, the aim of the present research has been to analyse the link between bubbling, fibre movement and critical flux, identified as the flux at which the transmembrane pressure (TMP) starts to rise. Tests were performed on vertical isolated fibres with a model feed of yeast suspension. The fibres were subject to steady bubbling from below. The parameters of interest were the fibre characteristics, such as tightness, diameter and length, as well as feed concentration. The results confirmed that the critical fluxes are affected by the fibre characteristics and feed concentration. Higher critical flux values can be achieved by using loose fibres, smaller diameters and longer fibres. The enhancement is partially linked to fibre movement and this is confirmed by improved performance when fibres are subject to mechanical movement in the absence of bubbling.

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

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