Effect of fluidized granular activated carbon (GAC) on critical flux in the microfiltration of particulate foulants

Jingwei Wang, Bing Wu, Yu Liu, Anthony G. Fane, Jia Wei Chew

Rannsóknarafurð: Framlag til fræðitímaritsGreinritrýni

24 Tilvitnanir (Scopus)

Útdráttur

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.

Upprunalegt tungumálEnska
Síður (frá-til)409-417
Síðufjöldi9
FræðitímaritJournal of Membrane Science
Bindi523
DOI
ÚtgáfustaðaÚtgefið - 1 feb. 2017

Athugasemd

Funding Information:
We gratefully acknowledge funding from the Nanyang Technological University iFood Research Grant, and the Singapore Ministry of Education Academic Research Funds Tier 2 (MOE2014-T2-2-074; ARC16/15) and Tier 1 (2015-T1-001-023). This study was also supported by research grant (1102-IRIS-02-01) provided by the Singapore National Research Foundation under its Environmental & Water Technologies Strategic Research Programme and administered by the Environment & Water Industry Programme Office (EWI) of the Public Utilities Board (PUB). The Economic Development Board (EDB) is also acknowledged for funding the Singapore Membrane Technology Centre (SMTC), Nanyang Technological University.

Publisher Copyright:
© 2016 Elsevier B.V.

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