Fouling control of submerged hollow fibre membranes by vibrations

Abstract In this study, we examine the improvement of fouling control of hollow fibre membranes with mechanical vibrations in the dead-end filtration of an inorganic suspension. Hollow fibres with diameters of 1.7 mm and 2 mm vibrating at moderate frequencies (0–15 Hz) and small amplitudes (0–12 mm) were submerged vertically in a 4 g/L Bentonite solution. Experiments were then conducted at both constant permeate flux and constant suction pressure conditions. The results showed that the membrane performance can be greatly improved when the vibration frequency or the vibration amplitude increases beyond a threshold magnitude. For example, over 90% reduction in the membrane fouling rate was achieved at 8 mm amplitude and 8 Hz frequency vibration compared to no vibration. Experiments were also conducted with 1% and 2% fibre looseness. The results showed that a small looseness can reduce the membrane fouling and increase the permeate flux under vibrations, which can be mainly attributed to the additional lateral movement of the fibres induced by the looseness. A comparison of vibrating the hollow fibres with and without the holding frame was also carried out to determine the effects of turbulence generated by the vibrating holding frame used in the experimental setup. Particle Image Velocimetry (PIV) measurements were performed to quantify the associated turbulence inside the membrane reactors. It was confirmed that the turbulence generated by the vibrating frame was more obvious at a high vibration frequency. However, it had little influence on the membrane filtration performance. Overall, the results from the present study confirm that at moderate frequencies, the cake layer resistance can be reduced substantially by vibration due to the dynamic shear enhancement on the membrane surface.

[1]  Anthony G Fane,et al.  Hydrodynamic effects of air sparging on hollow fiber membranes in a bubble column reactor. , 2013, Water research.

[2]  A. Fane,et al.  Hydrodynamic analysis of vibrating hollow fibre membranes , 2013 .

[3]  Adrian Wing-Keung Law,et al.  Factors affecting the performance of a submerged hollow fiber bundle , 2006 .

[4]  A. Fane,et al.  Analysis of constant permeate flow filtration using dead-end hollow fiber membranes , 2006 .

[5]  Jean-Christophe Schrotter,et al.  Membrane-aided biological wastewater treatment — an overview of applied systems , 2004 .

[6]  Wei Shi,et al.  Membrane interactions with NOM and an adsorbent in a vibratory shear enhanced filtration process (VSEP) system , 2008 .

[7]  A. Fane,et al.  The effect of vibration and coagulant addition on the filtration performance of submerged hollow fibre membranes , 2006 .

[8]  H. Gomaa,et al.  Flux enhancement using oscillatory motion and turbulence promoters , 2011 .

[9]  Yoshimasa Watanabe,et al.  Removal of humic substances with vibratory shear enhanced processing membrane filtration , 1998 .

[10]  Adrian Wing-Keung Law,et al.  The relationship between performance of submerged hollow fibers and bubble-induced phenomena examined by particle image velocimetry , 2007 .

[11]  M. Jaffrin,et al.  Local permeate flux–shear–pressure relationships in a rotating disk microfiltration module: implications for global performance , 2000 .

[12]  Usa. Fax.  New separation system extends the use of membranes , 1992 .

[13]  Kwang-Ho Choo,et al.  Membrane fouling mechanisms in the membrane-coupled anaerobic bioreactor , 1996 .

[14]  A. Al-Taweel,et al.  Intensification of membrane microfiltration using oscillatory motion , 2011 .

[15]  Michel Y. Jaffrin,et al.  Dynamic shear-enhanced membrane filtration: A review of rotating disks, rotating membranes and vibrating systems , 2008 .

[16]  Fenglin Yang,et al.  Rotating a helical membrane for turbulence enhancement and fouling reduction , 2012 .

[17]  Cristiano Piacsek Borges,et al.  The effects of long-term feeding of high organic loading in a submerged membrane bioreactor treating oil refinery wastewater , 2008 .

[18]  Michel Y. Jaffrin,et al.  An hydrodynamic investigation of microfiltration and ultrafiltration in a vibrating membrane module , 2002 .

[19]  A. Fane,et al.  The use of gas bubbling to enhance membrane processes , 2003 .

[20]  S. Low,et al.  A combined VSEP and membrane bioreactor system , 2005 .

[21]  Zhanfeng Cui,et al.  Gas sparging to enhance permeate flux in ultrafiltration using hollow fibre membranes , 1996 .

[22]  G. L. Sant'anna,et al.  The use of polyetherimide hollow fibres in a submerged membrane bioreactor operating with air backwashing , 2007 .

[23]  Vicki Chen,et al.  Fibre movement induced by bubbling using submerged hollow fibre membranes , 2006 .

[24]  G. Jonsson,et al.  Dynamic Microfiltration with a Vibrating Hollow Fiber Membrane Module: Filtration of Yeast Suspensions , 2006 .

[25]  M. Bilad,et al.  Novel magnetically induced membrane vibration (MMV) for fouling control in membrane bioreactors. , 2012, Water research.

[26]  E. Ravina,et al.  The Vibrating Ultrafiltration Module. Performance in the 50–1000 Hz Frequency Range , 1993 .

[27]  Adrian Wing-Keung Law,et al.  Measurement of mixing processes with combined digital particle image velocimetry and planar laser induced fluorescence , 2000 .

[28]  S. Delgado,et al.  Effect of the shear intensity on fouling in submerged membrane bioreactor for wastewater treatment , 2008 .

[29]  Hassan Gomaa,et al.  Analysis of flux enhancement at oscillating flat surface membranes , 2011 .

[30]  Michel Y. Jaffrin,et al.  Concentration of total milk proteins by high shear ultrafiltration in a vibrating membrane module , 2005 .

[31]  M. Jaffrin,et al.  Treatment of dairy process waters modelled by diluted milk using dynamic nanofiltration with a rotating disk module , 2006 .

[32]  Anastasios I. Zouboulis,et al.  Vibratory shear enhanced processing membrane filtration applied for the removal of natural organic matter from surface waters , 2006 .