Effect of fluidized granular activated carbon (GAC) on critical flux in the microfiltration of particulate foulants
The fluidization of Granular Activated Carbon (GAC) particles has received much attention in recent years as a promising method for mitigating membrane fouling particularly in membrane bioreactors (MBRs). In particular, the fluidized GAC particles are acknowledged to be beneficial in terms of adsorp...
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
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2017
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| Online Access: | https://hdl.handle.net/10356/85579 http://hdl.handle.net/10220/43788 |
| _version_ | 1811687740938387456 |
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| author | Chew, Jia Wei Wang, Jingwei Wu, Bing Liu, Yu Fane, Anthony Gordon |
| author2 | School of Chemical and Biomedical Engineering |
| author_facet | School of Chemical and Biomedical Engineering Chew, Jia Wei Wang, Jingwei Wu, Bing Liu, Yu Fane, Anthony Gordon |
| author_sort | Chew, Jia Wei |
| collection | NTU |
| description | The fluidization of Granular Activated Carbon (GAC) particles has received much attention in recent years as a promising method for mitigating membrane fouling particularly in membrane bioreactors (MBRs). In particular, the fluidized GAC particles are acknowledged to be beneficial in terms of adsorption of organic foulants, and mechanical scouring and surface shear of the membrane surface. Both lab-scale and pilot-scale studies have affirmed the efficacy of GAC fluidization in maintaining a depressed extent of membrane fouling in anaerobic fluidized bed - membrane bioreactors (AnFMBRs). More in-depth studies have also correlated the hydrodynamics of fluidized GAC particles with the effectiveness of membrane fouling mitigation. This study aimed at understanding the improvement of fine (micron-sized) particle critical flux in the presence of fluidized GAC via the Direct Observation Through the Membrane (DOTM) technique. The model foulant was a suspension of polystyrene particles (5 µm sized), and the parameters investigated included GAC particle diameter (dp), superficial liquid velocity (Ul) and thereby power requirement (Pr), and height along the vertically aligned membrane. Results indicate that: (i) fluidized GAC increased the critical flux by an order-of-magnitude relative to that with tangential liquid shear alone; (ii) the overall critical flux (Jcritical, overall) expectedly increased with power input (Pr), but the relationship between local critical flux (Jcritical) and power input (Pr) depended on the position along the membrane height; (iii) at the same Pr, although the larger GAC particles were more effective locally (i.e., higher Jcritical) due to greater particle inertia, the smaller GAC particles were more effective overall (i.e., higher Jcritical, overall) due to greater bed expansion enabling scouring of more membrane heights; and (iv) a higher power input (Pr) was required for sufficient bed expansion to enable more consistent critical flux (Jcritical) values over the whole membrane height. |
| first_indexed | 2024-10-01T05:21:07Z |
| format | Journal Article |
| id | ntu-10356/85579 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T05:21:07Z |
| publishDate | 2017 |
| record_format | dspace |
| spelling | ntu-10356/855792020-03-07T11:35:27Z Effect of fluidized granular activated carbon (GAC) on critical flux in the microfiltration of particulate foulants Chew, Jia Wei Wang, Jingwei Wu, Bing Liu, Yu Fane, Anthony Gordon School of Chemical and Biomedical Engineering School of Civil and Environmental Engineering Interdisciplinary Graduate School (IGS) Advanced Environmental Biotechnology Centre (AEBC) Nanyang Environment and Water Research Institute Singapore Membrane Technology Centre Membrane fouling mitigation Liquid-solid fluidization The fluidization of Granular Activated Carbon (GAC) particles has received much attention in recent years as a promising method for mitigating membrane fouling particularly in membrane bioreactors (MBRs). In particular, the fluidized GAC particles are acknowledged to be beneficial in terms of adsorption of organic foulants, and mechanical scouring and surface shear of the membrane surface. Both lab-scale and pilot-scale studies have affirmed the efficacy of GAC fluidization in maintaining a depressed extent of membrane fouling in anaerobic fluidized bed - membrane bioreactors (AnFMBRs). More in-depth studies have also correlated the hydrodynamics of fluidized GAC particles with the effectiveness of membrane fouling mitigation. This study aimed at understanding the improvement of fine (micron-sized) particle critical flux in the presence of fluidized GAC via the Direct Observation Through the Membrane (DOTM) technique. The model foulant was a suspension of polystyrene particles (5 µm sized), and the parameters investigated included GAC particle diameter (dp), superficial liquid velocity (Ul) and thereby power requirement (Pr), and height along the vertically aligned membrane. Results indicate that: (i) fluidized GAC increased the critical flux by an order-of-magnitude relative to that with tangential liquid shear alone; (ii) the overall critical flux (Jcritical, overall) expectedly increased with power input (Pr), but the relationship between local critical flux (Jcritical) and power input (Pr) depended on the position along the membrane height; (iii) at the same Pr, although the larger GAC particles were more effective locally (i.e., higher Jcritical) due to greater particle inertia, the smaller GAC particles were more effective overall (i.e., higher Jcritical, overall) due to greater bed expansion enabling scouring of more membrane heights; and (iv) a higher power input (Pr) was required for sufficient bed expansion to enable more consistent critical flux (Jcritical) values over the whole membrane height. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) EDB (Economic Devt. Board, S’pore) 2017-09-22T05:23:18Z 2019-12-06T16:06:28Z 2017-09-22T05:23:18Z 2019-12-06T16:06:28Z 2016 Journal Article Wang, J., Wu, B., Liu, Y., Fane, A. G., & Chew, J. W. (2017). Effect of fluidized granular activated carbon (GAC) on critical flux in the microfiltration of particulate foulants. Journal of Membrane Science, 523, 409-417. 0376-7388 https://hdl.handle.net/10356/85579 http://hdl.handle.net/10220/43788 10.1016/j.memsci.2016.09.039 en Journal of Membrane Science © 2016 Elsevier |
| spellingShingle | Membrane fouling mitigation Liquid-solid fluidization Chew, Jia Wei Wang, Jingwei Wu, Bing Liu, Yu Fane, Anthony Gordon Effect of fluidized granular activated carbon (GAC) on critical flux in the microfiltration of particulate foulants |
| title | Effect of fluidized granular activated carbon (GAC) on critical flux in the microfiltration of particulate foulants |
| title_full | Effect of fluidized granular activated carbon (GAC) on critical flux in the microfiltration of particulate foulants |
| title_fullStr | Effect of fluidized granular activated carbon (GAC) on critical flux in the microfiltration of particulate foulants |
| title_full_unstemmed | Effect of fluidized granular activated carbon (GAC) on critical flux in the microfiltration of particulate foulants |
| title_short | Effect of fluidized granular activated carbon (GAC) on critical flux in the microfiltration of particulate foulants |
| title_sort | effect of fluidized granular activated carbon gac on critical flux in the microfiltration of particulate foulants |
| topic | Membrane fouling mitigation Liquid-solid fluidization |
| url | https://hdl.handle.net/10356/85579 http://hdl.handle.net/10220/43788 |
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