• Title, Summary, Keyword: Filtration resistance

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Study on Filtration Characteristics of Wood Pulp and Non-Wood Fiber (목재펄프 및 비목재 섬유의 여과제 특성에 관한 연구)

  • Cho, Jun-Hyung;Han, James S.;Lee, Beom-Goo
    • Journal of the Korean Wood Science and Technology
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    • v.26 no.4
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    • pp.86-91
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    • 1998
  • The drainage was used to determine the specific filtration resistance for wood and non-wood fibers. The drainage rate is also affected by factors that can be changed on consistency, pressure drop across the mat, basis weight, additives, and viscosity. Recent development of theoretical studies in flow through porous media and filtration operation emphasize the urgent need for more accurate data for porosity and specific filtration resistance. This study was investigated to determine specific filtration resistance of Hw, Sw-BKP and Kenaf fiber by filtration experimental. Freeness levels selected were 150,250,and $350m\ell$ CSF. The average specific filtration resistance decreased as freeness increased and resistance of Sw-BKP was greater than that of Hw-BKP. The filtrate and porosity increased and specific filtration resistance decreased as particle size of fiber increased.

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Changes of Average Specific Resistance on Suspension Concentration (현탁액의 농도에 다른 여과 현균비저항값의 변화)

  • 장재선
    • Journal of Environmental Health Sciences
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    • v.22 no.1
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    • pp.12-20
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    • 1996
  • This study was carried out to investigate the change of average .specific resistance according to suspension concentration for study phenomena occurring during filtration period. As the results of this study, the following conclusions were obtained. The average specific resistance in 1% $CaCO_3$ suspension was showed power function(R=0.99), whereas in TOYO 5C and TOYO 5A paper were made little difference under high pressure. It represented from results that filtration theory in concord with cake filtration was no affected the average specific resistance of filter medium in cake filtration. In case of 0.1% $CaCO_3$ suspension filtration, the TOYO 5C was showed power function, whereas in TOYO 5A paper differently. In the present study, the $P_1$ value was calculated from the average specific resistance by filtration method. Therefore, $P_1$ value were $1.68\times 10^4Pa$, $4.05\times 10^3Pa$, and $3.15\times 10^3Pa$ in $5.3\times 10^4Pa$, $1.3\times 10^4Pa$, and $8.2\times 10^3Pa$, respectively. We concluded that propriety of new filtration theory was also proved.

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Filtration Resistance with Flow Rate on Membrane Surface in Treating Wastewater by Membrane Bioreactor (하수 MBR공정에 있어서 막표면 유속과 여과저항)

  • Hyun, Kil-Soo
    • Journal of Korean Society of Water Science and Technology
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    • v.25 no.4
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    • pp.115-120
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    • 2017
  • Membrane fouling patterns in membrane bioreactor (MBR) include blockage of membrane pore, gel layer formation and sludge cake deposition on the membrane surface. Stirred dead-cell filtration has been widely used for fundamental studies on membrane fouling caused by soluble and colloidal matter during membrane filtration. In this study, the performance of MBR using a dead-end stirrer cell was carried out to investigate the characteristics of pollutants removal and membrane filtration resistance with hydraulic shear force on the surface of membrane module. Influent water qualities were on average <65 mgCOD/L, <21 mgT-N/L, and <6 mgT-P/L, <4500 mgMLSS/L, respectively. As a result, the membrane biofiltration achieved higher efficiencies of COD and T-P except T-N having lower efficiency <50% regardless of the hydraulic shear force. An increase in the hydraulic shear force resulted in a decrease in both transmembrane pressure (TMP) and total membrane filtration resistance. This suggests that higher hydraulic shear force is needed to improve membrane filtration resistance in operating a long-term filtration of MBR having a suitable permeate flux to enhance nitrogen removal efficiency.

A Study on the Factors Affecting Cake Filtration (케이크 여과에 영향을 미치는 요인에 관한 연구)

  • 장재선
    • Journal of Environmental Health Sciences
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    • v.21 no.2
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    • pp.7-11
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    • 1995
  • This study was carried out to investigate the change of average specific resistance according to filtration pressure, suspension concentration and filters for study phenomena occurring in cake filtration. As the results of this study, the following conclusions were obtained. It was estimated that the average specific resistance of filtration Was decreased in proportion to decreased of filtration pressure. But in very pressure, average specific resistance was increased. The average specific resistance value on filter medium by various pressure was showed as same trends under constant suspension concentration. This phenomenon was though that a carrain amount of fine particles in the cake was found to migrate throught the cake in the case of very thin at very low pressure. In relation to the change of suspension concentration, average specific resistance value become low according to decreased in supension concentration.

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Specific Resistance (K2´) of Dust Layer Deposited on Porous Media (다공성 필터에서의 여과 분진층 비저항 연구)

  • 이선희;이경미;조영민
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.3
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    • pp.371-380
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    • 2004
  • In the dust separation by using porous filter media, the structure of dust layer deposited on the filter surface of filter medium directly affects the effective filtration. The present study has investigated the specific resistance (K$_2$') of the dust layer and its porosity ($\varepsilon$$_{c}$) for three different filters; FA composite filter, metal fiber filter and stainless filter. The specific resistance (K$_2$') increased and at the same time the cake porosity ($\varepsilon$$_{c}$) decreased with the increase of filtration velocity, possibly due to the compressible effect of dust layer. However, under the low dust concentration, subsequent dust particles would block the open channels through the layer resulting in high specific resistance of the layer. The FA composite filter among three filters was shown to be the most effective filter for dust cake filtration at low filtration velocities less than 0.1 m/s for an approximate dust concentration of 5 g/㎥.

THE EFFECT OF AIR BUBBLES FROM DISSOLVED GASES ON THE MEMBRANE FOULING IN THE HOLLOW FIBER SUBMERGED MEMBRANE BIO-REACTOR (SMBR)

  • Jang, Nam-Jung;Yeo, Young-Hyun;Hwang, Moon-Hyun;Vigneswaran, Saravanamuthu;Cho, Jae-Weon;Kim, In S.
    • Environmental Engineering Research
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    • v.11 no.2
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    • pp.91-98
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    • 2006
  • There is a possibility of the production of the air bubbles in membrane pores due to the reduction in pressure during membrane filtration. The effect of fine air bubbles from dissolved gases on microfiltration was investigated in the submerged membrane bio-reactor (SMBR). The $R_{air}$ (air bubble resistance) was defined as the filtration resistance due to the air bubbles formed from the gasification of dissolved gases. From the results of filtration tests using pure water with changes in the dissolved oxygen concentration, the air bubbles from dissolved gases were confirmed to act as a foulant and; thus, increase the filtration resistance. The standard pore blocking and cake filtration models, SPBM and CFM, respectively, were applied to investigate the mechanism of air bubble fouling on a hollow fiber membrane. However, the application of the SPBM and CFM were limited in explaining the mechanism due to the properties of air bubble. With a simple comparison of the different filtration resistances, the $R_{air}$ portion was below 1% of the total filtration resistance during sludge filtration. Therefore, the air bubbles from dissolved gases would only be a minor foulant in the SMBR. However, under the conditions of a high gasification rate from dissolved gases, the effect of air bubble fouling should be considered in microfiltration.

Filtration with Sedimentation II: New Analysis and Solid Mass Fraction of Suspension Entering Cake (침전이 수반되는 케이크 여과 II: 새로운 분석과 케이크에 도입되는 현탁액의 고체 질량분율)

  • Yim, Sung Sam
    • Korean Chemical Engineering Research
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    • v.50 no.3
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    • pp.535-544
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    • 2012
  • Filtration on horizontal filter medium facing upward is accompanied by sedimentation. When sedimentation phenomenon is not considered, the average specific cake resistance by filtration could be in error more than two times. In the previous paper on this subject, it was insisted that the solid mass fraction of suspension changes in filtration period by sedimentation. But we could not find out the degree of change. At the first half of this paper, the average specific cake resistance measured by permeation will be proved to be exact in several means. The average specific cake resistance conventionally measured by filtration does not give correct results because it uses initial solid mass fraction of suspension. Then we calculated the changed solid mass fraction of suspension due to sedimentation during filtration by the experimental values obtained "filtration-permeation" method. We also determined the solid mass fraction at a certain moment of filtration from the suspension height and a new equation derived in this study. The two results were compared and proven that they almost matched.

The Effect of Chemical Backwash on Filtration Performance of Batch Membrane Filtration System (회분식 막여과 시스템에서 약품역세가 여과성능에 미치는 영향)

  • Kim, Kwan Yeop;Lee, Eui Jong;Kwon, Jin Sub;Kim, Hyung Soo
    • Journal of Korean Society of Water and Wastewater
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    • v.23 no.6
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    • pp.855-864
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    • 2009
  • The main object of this work was to determine the influence of periodic chemical backwash on filtration resistance in membrane filtration system. In this work Hermia's models were used to investigate the fouling mechanisms involved in the microfiltration of $0.45{\mu}m$ filtered sewage feed. Batch microfiltration experiments were performed at transmembrane pressure 0.4 bar and different feed SCOD concentration (9~67 mgSCOD/L). The results showed that the best fit to experimental data corresponded to the intermediate blocking model followed by the standard and complete blocking model for all the experimental conditions tested. From the simulation results of filtration performance, it was found that in order to maintain sustainable operation of membrane filtration system, irreversible foulant component accumulated continuously on membrane surface and/or pore must be effectively removed. In addition, it was verified that periodic chemical backwash using NaOCl or NaOH effectively improved filtration performance of membrane.

Experimental Analysis on Filtration-Permeation: Influence of the Type and Sheets of Filter Media, and Filtration Pressure (여과-투과에 대한 실험적 분석: 여과매체의 종류, 여과매체의 매수, 여과압력의 영향)

  • Yim, Sung-Sam;Song, Yun-Min
    • Korean Chemical Engineering Research
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    • v.50 no.2
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    • pp.317-327
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    • 2012
  • The average specific cake resistance, the most important indicator for cake filtration and solid-liquid separation, is measured by filtration experiment. But the exact value is difficult to measure because of the other influences such as sedimentation during filtration. This study, a little more stable method named filtration-permeation is proposed for measuring average specific cake resistance. The filtration-permeation is composed of permeation of particle eliminated water through pre-formed cake by filtration. Using 1 wt% calcium carbonate suspension, the filtration-permeation experiments were performed for 8 kinds of filter media at the conditions of 0.5 atm and 0.2 atm, 1 and 3 sheets of filter media. At each specific condition, three to five times filtration-permeation were accomplished. As a result, stable permeation speed is measured. According to this experimental result, the characteristics of permeation and the effect of sedimentation are analyzed with Ruth's equation. The one way analysis of variance (one way ANOVA) is applied to the average specific cake resistances of filtration and permeation obtained with the selected three kinds of filter media. The average specific cake resistances between 0.5 atm and 0.2 atm by filtration do not distinguished, but those by permeation is perfectly distinguished. The experimental results during permeation have a very narrow distribution than that measured during filtration. The analysis of filtration experiments, it was verified that the resistance of filter medium by traditional method is of no significance. Finally, the migration of small particles through the medium composed of fiber glass at low pressure was studied.

Effect of sludge concentration on sludge dewaterability and cake clogging analysis (슬러지의 탈수성(脫水性)에 대한 농도(濃度)의 영향(影響)과 케이크 폐색현상(閉塞現象)의 해석(解析))

  • Kwon, Jae Hyun;Park, Chung Hyun
    • Journal of Korean Society of Water and Wastewater
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    • v.10 no.1
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    • pp.85-95
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    • 1996
  • Although the specific resistance to filtration is the most frequently employed means for characterizing dewaterability of a sludge, it presently is not possible to design nor to prediet performance of dewatering facilities using traditional linearized parabolic filtration equation, that is, the specific resistance model because of theoretical and practical inadequacies of the concept. Limitations of the specific resistance model reflect the need to examine fundamental sludge properties and filtration behaviors affecting dewaterability. From this study, two major limitations of the specific resistance model were noted. First, specific resistance values are very dependent on the sludge concentration because of the variations of particle size distribution and cake clogging to occur when surface area mean diameter is less than $25{\mu}m$ for activated sludge, $18{\mu}m$ for water treatment plant sludge. Second, nonparabolic filtration behavior can result from cake clogging, caused by the migration of fine particles into the cake pores, accelated by skin effect with highly compressible sludges.

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