Dean Vortices with Wall Flux in a Curved Channel Membrane System: 3. Concentration Polarization in a Spiral Reverse Osmosis Slit.

1998 ◽  
Vol 31 (5) ◽  
pp. 683-693 ◽  
Author(s):  
Kun Yong Chung ◽  
Mary E. Brewster ◽  
Georges Belfort
Keyword(s):  
Reverse Osmosis ◽  
Concentration Polarization ◽  
Membrane System ◽  
Curved Channel ◽  
Dean Vortices

Dean vortices with wall flux in a curved channel membrane system

1993 ◽  
Vol 81 (1-2) ◽  
pp. 127-137 ◽  
Author(s):  
Mary E. Brewster ◽  
Kun-Yong Chung ◽  
Georges Belfort
Keyword(s):  
Membrane System ◽  
Curved Channel ◽  
Dean Vortices

Dean vortices with wall flux in a curved channel membrane system.

1993 ◽  
Vol 81 (1-2) ◽  
pp. 151-162 ◽  
Author(s):  
Kun Yong Chung ◽  
William A. Edelstein ◽  
Georges Belfort
Keyword(s):  
Membrane System ◽  
Curved Channel ◽  
Dean Vortices

Dean vortices with wall flux in a curved channel membrane system

1993 ◽  
Vol 81 (1-2) ◽  
pp. 139-150 ◽  
Author(s):  
Kun Yong Chung ◽  
Ronald Bates ◽  
George Belfort
Keyword(s):  
Membrane System ◽  
Curved Channel ◽  
Dean Vortices

Dean vortices with wall flux in a curved channel membrane system: 2. The velocity field

AIChE Journal ◽  
1996 ◽  
Vol 42 (2) ◽  
pp. 347-358 ◽  
Author(s):  
Kun Yong Chung ◽  
Mary E. Brewster ◽  
Georges Belfort
Keyword(s):  
Velocity Field ◽  
Membrane System ◽  
Curved Channel ◽  
Dean Vortices ◽  
System 2

scholarly journals The Role of Gravity in the Evolution of the Concentration Field in the Electrochemical Membrane Cell

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 680 ◽  
Author(s):  
Kornelia M. Batko ◽  
Andrzej Ślęzak ◽  
Wioletta M. Bajdur
Keyword(s):  
Boundary Layers ◽  
Concentration Polarization ◽  
Concentration Field ◽  
Membrane System ◽  
Volume Transport ◽  
Cellulose Acetate Membrane ◽  
Concentration Boundary ◽  
Concentration Boundary Layers ◽  
Mechanical Stirring

The subject of the study was the osmotic volume transport of aqueous CuSO4 and/or ethanol solutions through a selective cellulose acetate membrane (Nephrophan). The effect of concentration of solution components, concentration polarization of solutions and configuration of the membrane system on the value of the volume osmotic flux ( J v i r ) in a single-membrane system in which the polymer membrane located in the horizontal plane was examined. The investigations were carried out under mechanical stirring conditions of the solutions and after it was turned off. Based on the obtained measurement results J v i r , the effects of concentration polarization, convection polarization, asymmetry and amplification of the volume osmotic flux and the thickness of the concentration boundary layers were calculated. Osmotic entropy production was also calculated for solution homogeneity and concentration polarization conditions. Using the thickness of the concentration boundary layers, critical values of the Rayleigh concentration number ( R C r ), i.e., the switch, were estimated between two states: convective (with higher J v i r ) and non-convective (with lower J v i r ). The operation of this switch indicates the regulatory role of earthly gravity in relation to membrane transport.

scholarly journals Recycling of Reverse Osmosis Concentrates to the Membrane Bioreactor in the MBR-RO Process for Water Reuse: effect on mbr performances

2017 ◽  
Vol 30 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Thi Thu Nga Vu ◽  
Manon Montaner ◽  
Christelle Guigui
Keyword(s):  
Organic Matter ◽  
Reverse Osmosis ◽  
Membrane Fouling ◽  
Water Reuse ◽  
High Performance ◽  
Membrane Bioreactor ◽  
Membrane System ◽  
Size Exclusion ◽  
Ro Concentrate ◽  
The Impact

Wastewater effluents can be treated by an integrated membrane system combining membrane bioreactor (MBR) and reverse osmosis (RO) for effective removal of micropollutants in the field of high-quality water reuse. However, discharging the RO concentrate waste stream directly into the natural environment could lead to serious problems due to the toxic components contained in the concentrates (micropollutants, salts, organic matter). A possible solution could be the recirculation of RO concentrate waste to the MBR. However, such an operation should be studied in detail since the recirculation of non-biodegradable organic matter or high concentrations of salts and micropollutants could directly or indirectly contribute to MBR membrane fouling and modification of the biodegradation activity. In this context, the work reported here focused on the recirculation of such concentrates in an MBR, paying specific attention to MBR membrane fouling. Lab-scale experiments were performed on a continuous MBR-RO treatment line with RO concentrate recirculation. The main goal was to determine the recovery of the RO unit and of the global process that maintained good process performance in terms of biodegradation and MBR fouling. The results demonstrate that the impact of the toxic flow on activated sludge depends on the recovery of the RO step but the same trends were observed regardless of the organic matter and salt contents of the concentrates: the concentration of proteins increased slightly. Size-exclusion high performance liquid chromatography (HPLC-SEC) was employed to study the effects of RO concentrate on the production of protein-like soluble microbial products (SMPs) and demonstrated a significant peak of protein-like substances corresponding to 10-100 kDa and 100-1 000 kDa molecules in the supernatant. Thus a significant increase in the propensity for sludge fouling was observed, which could be attributed to the increased quantity of protein-like substances. Finally, the effect of the concentrate on sludge activity was studied and no significant effect was observed on biodegradation, indicating that the return of the concentrate to the MBR could be a good alternative.

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