Direct microscopic observation of forward osmosis membrane fouling by microalgae: Critical flux and the role of operational conditions

2013 ◽  
Vol 436 ◽  
pp. 174-185 ◽  
Author(s):  
Shan Zou ◽  
Yi-Ning Wang ◽  
Filicia Wicaksana ◽  
Theingi Aung ◽  
Philip Chuen Yung Wong ◽  
...  
Keyword(s):  
Membrane Fouling ◽  
Microscopic Observation ◽  
Forward Osmosis ◽  
Critical Flux ◽  
Operational Conditions ◽  
Direct Microscopic Observation

Direct Microscopic Observation of Forward Osmosis Membrane Fouling

2010 ◽  
Vol 44 (18) ◽  
pp. 7102-7109 ◽  
Author(s):  
Yining Wang ◽  
Filicia Wicaksana ◽  
Chuyang Y. Tang ◽  
Anthony G. Fane
Keyword(s):  
Membrane Fouling ◽  
Microscopic Observation ◽  
Forward Osmosis ◽  
Direct Microscopic Observation

Comparative investigation on the impact of polymeric substances on membrane fouling during sub-critical and critical flux operation of a municipal membrane bioreactor

2008 ◽  
Vol 58 (9) ◽  
pp. 1849-1855 ◽  
Author(s):  
S. Lyko ◽  
T. Wintgens ◽  
T. Melin
Keyword(s):  
Membrane Fouling ◽  
Pilot Scale ◽  
Comparative Investigation ◽  
Hollow Fibre ◽  
Size Exclusion ◽  
Dominant Factor ◽  
Permeate Flux ◽  
Critical Flux ◽  
Operational Conditions ◽  
The Impact

Soluble organic macromolecules are ubiquitous in activated sludge supernatant. For the operation of membrane bioreactors (MBR) this group of substances is considered as the dominant factor causing severe membrane fouling due to the concentration polarisation phenomenon. The well established critical flux concept for the characterisation of membrane bioreactor's operation limits is based on filtration data only. As there is an cause-and-effect relation between the partial retention of organic compounds and the limited flux according the critical flux concept the aim of this study was to draw a comparison between different permeate fluxes on the retention of organic macromolecules. Thus, a municipal pilot-scale MBR with three capillary hollow fibre membrane modules was operated in sub critical, critical and supercritical flux mode, respectively and the retention of macromolecules was quantified by size exclusion chromatography. Three permeate extraction pumps allow a simultaneous operation with different operational conditions for each membrane module and proved the crucial impact of permeate flux on the fouling rate. The interchange of these conditions gave evidence of an optimised start-up procedure for MBRs characterised by higher permeate fluxes. An increased flux causes both a higher retention of soluble macromolecules and subsequent a higher fouling rate.

scholarly journals A Review of Fouling Mechanisms, Control Strategies and Real-Time Fouling Monitoring Techniques in Forward Osmosis

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 695 ◽  
Author(s):  
Ibrar Ibrar ◽  
Osamah Naji ◽  
Adel Sharif ◽  
Ali Malekizadeh ◽  
Alaa Alhawari ◽  
...  
Keyword(s):  
Real Time ◽  
Membrane Fouling ◽  
Control Strategies ◽  
Forward Osmosis ◽  
Future Research ◽  
Negative Consequences ◽  
Critical Flux ◽  
Monitoring Technologies ◽  
And Control ◽  
The Impact

Forward osmosis has gained tremendous attention in the field of desalination and wastewater treatment. However, membrane fouling is an inevitable issue. Membrane fouling leads to flux decline, can cause operational problems and can result in negative consequences that can damage the membrane. Hereby, we attempt to review the different types of fouling in forward osmosis, cleaning and control strategies for fouling mitigation, and the impact of membrane hydrophilicity, charge and morphology on fouling. The fundamentals of biofouling, organic, colloidal and inorganic fouling are discussed with a focus on recent studies. We also review some of the in-situ real-time online fouling monitoring technologies for real-time fouling monitoring that can be applicable to future research on forward osmosis fouling studies. A brief discussion on critical flux and the coupled effects of fouling and concentration polarization is also provided.

scholarly journals Critical flux-based membrane fouling control of forward osmosis: Behavior, sustainability, and reversibility

2019 ◽  
Vol 570-571 ◽  
pp. 380-393 ◽  
Author(s):  
Thanh-Tin Nguyen ◽  
Seungho Kook ◽  
Chulmin Lee ◽  
Robert W. Field ◽  
In S. Kim
Keyword(s):  
Membrane Fouling ◽  
Forward Osmosis ◽  
Critical Flux ◽  
Fouling Control

scholarly journals Role of Operating Conditions in a Pilot Scale Investigation of Hollow Fiber Forward Osmosis Membrane Modules

Membranes ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 66 ◽  
Author(s):  
Victoria Sanahuja-Embuena ◽  
Gabriel Khensir ◽  
Mohamed Yusuf ◽  
Mads Friis Andersen ◽  
Xuan Tung Nguyen ◽  
...  
Keyword(s):  
Hollow Fiber ◽  
Dominant Role ◽  
Forward Osmosis ◽  
Pilot Scale ◽  
Extensive Study ◽  
Operating Conditions ◽  
Great Promise ◽  
Operational Conditions ◽  
Membrane Modules

Although forward osmosis (FO) membranes have shown great promise for many applications, there are few studies attempting to create a systematization of the testing conditions at a pilot scale for FO membrane modules. To address this issue, hollow fiber forward osmosis (HFFO) membrane modules with different performances (water flux and solute rejection) have been investigated at different operating conditions. Various draw and feed flow rates, draw solute types and concentrations, transmembrane pressures, temperatures, and operation modes have been studied using two model feed solutions—deionized water and artificial seawater. The significance of the operational conditions in the FO process was attributed to a dominant role of concentration polarization (CP) effects, where the selected draw solute and draw concentration had the biggest impact on membrane performance due to internal CP. Additionally, the rejection of the HFFO membranes using three model solutes (caffeine, niacin, and urea) were determined under both FO and reverse osmosis (RO) conditions with the same process recovery. FO rejections had an increase of 2% for caffeine, 19% for niacin, and 740% for urea compared to the RO rejections. Overall, this is the first extensive study of commercially available inside-out HFFO membrane modules.

Optimising the operation of a MBR pilot plant by quantitative analysis of the membrane fouling mechanism

2005 ◽  
Vol 51 (6-7) ◽  
pp. 19-25 ◽  
Author(s):  
T. Jiang ◽  
M.D. Kennedy ◽  
B.F. Guinzbourg ◽  
P.A. Vanrolleghem ◽  
J.C. Schippers
Keyword(s):  
Membrane Fouling ◽  
Pilot Plant ◽  
Filter Cake ◽  
Municipal Wastewater ◽  
Hollow Fibre ◽  
Critical Flux ◽  
Membrane Pore ◽  
Operational Conditions ◽  
Temperature Conditions ◽  
Filtration Flux

In order to optimize some operational conditions of MBR systems, a MBR pilot plant equipped with a submerged hollow fibre membrane module was employed in this study. The pilot MBR was fed with real municipal wastewater and the filtration flux, backwashing interval, aeration frequency and temperature were varied. A filtration flux below 25 l/m2h is generally recommended, at below this flux, the MBR operated at sub-critical flux conditions, the filter cake was minimized and membrane fouling was mainly attributed to the membrane pore blocking. Moreover, the membrane fouling, at below 25 l/m2h, was more reversible to backwashing; above this value, backwashing became less efficient to clean the membrane. Less frequent backwashing (e.g. 600 s filtration/45 s backwashing) decreased the amount of fouling irreversible to backwashing and its performance was superior to that of frequent backwashing (e.g. 200 s filtration/15 s backwashing). The MBR suffered more fouling at low temperature conditions (e.g. at 13–14 °C) than at high temperature conditions (e.g. at 17–18 °C). A conceptual model was built up and successfully interpreted this temperature effect.

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