Organic fouling development in a long channel RO membrane cell

This study was to experimentally investigate organic fouling development in a 1-m long RO membrane channel using alginate as a model organic compound. Five parallel local permeate fluxes with a distance interval of 20 cm along the channel were monitored continuously during the organic filtration tests. It was found that organic fouling became more severe towards the outlet of the channel. This might be mainly attributed to the salt concentration polarization formation along the channel. The higher salt concentration downstream increased the interactions involved in organic fouling such as charge-screening and alginate-calcium bridging, which intensively promoted organic fouling formation in the downstream. A higher feed flow was a common option to mitigate fouling at most lab-scale RO research work, but not the case in this long membrane channel. A higher feed flow changed the organic fouling development profile along the channel, but would not eliminate organic fouling.

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An experimental study on the effect of spacer on concentration polarization in a long channel reverse osmosis membrane cell

Water Science & Technology ◽

10.2166/wst.2010.116 ◽

2010 ◽

Vol 61 (8) ◽

pp. 2035-2041 ◽

Cited By ~ 7

Author(s):

H. Mo ◽

H. Y. Ng

Keyword(s):

Membrane Fouling ◽

Concentration Polarization ◽

Permeate Flux ◽

Membrane Channel ◽

Organic Fouling ◽

Integral Effect ◽

Ro Membrane ◽

Long Channel ◽

Membrane Cell ◽

Extra Resistance

This study was to experimentally investigate the performance and organic fouling behaviour in a 1-m long RO membrane channel with or without spacer for desalting. It was found that local permeate flux distributed heterogeneously along the long membrane channel without a spacer inserted due to exponential growth of concentration polarization, which also resulted in decreasing salt rejection and increasing organic fouling along the membrane channel in the downstream direction. This heterogeneity could be lessened by inserting a spacer into the channel, which mitigated concentration polarization due to the enhanced turbulence caused by a spacer, especially at the downstream portion of the channel. However, in the upstream of the channel, inserting a spacer exerted an additional vertical resistance which might counteract the effect of concentration polarization mitigation by a spacer and caused a lower permeate flux. This suggests that it is necessary to consider the integral effect of spacer for designing an RO membrane module and an overall RO system in order to prevent extra resistance, reduce concentration polarization and membrane fouling.

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Impact of pretreatment on RO membrane organic fouling: composition and adhesion of tertiary wastewater effluent organic matter

Environmental Science Water Research & Technology ◽

10.1039/d0ew01098g ◽

2021 ◽

Author(s):

Nadine Siebdrath ◽

Bertram Skibinski ◽

Shiju Abraham ◽

Roy Bernstein ◽

Robert Berger ◽

...

Keyword(s):

Organic Matter ◽

Wastewater Effluent ◽

Effluent Organic Matter ◽

Membrane Performance ◽

Organic Fouling ◽

Ro Membrane

Organic fouling in RO desalination of tertiary wastewater is of major concern in the decline in membrane performance.

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Topology Optimization of Spacers for Maximizing Permeate Flux on Membrane Surface in Reverse Osmosis Channel

Volume 5: 37th Design Automation Conference, Parts A and B ◽

10.1115/detc2011-48933 ◽

2011 ◽

Author(s):

Seungjae Oh ◽

Semyung Wang ◽

Minkyu Park ◽

Joonha Kim

Keyword(s):

Topology Optimization ◽

Pressure Drop ◽

Reverse Osmosis ◽

Membrane Surface ◽

Design Development ◽

Permeate Flux ◽

Membrane Channel ◽

Initial Attempt ◽

Membrane Surfaces ◽

Ro Membrane

The objective of this study is to design spacers using fluid topology optimization in 2D crossflow Reverse Osmosis (RO) membrane channel to improve the performance of RO processes. This study is an initial attempt to apply topology optimization to designing spacers in RO membrane channel. The performance was evaluated by the quantity of permeate flux penetrating both upper and lower membrane surfaces. A coupled Navier-Stokes and Convection-Diffusion model was employed to calculate the permeate flux. To get reliable solutions, stabilization methods were employed with standard finite element method. The nine reference models which consist of the combination of circle, rectangular, triangle shape and zigzag, cavity, submerge configuration of spacers were simulated. Such models were compared with new model designed by topology optimization. The permeate flux at both membrane surfaces was determined as an objective function. In addition, permissible pressure drop along the channel and spacer volume were used as constraints. As a result of topology optimization as the permissible pressure drop changes in channel, characteristics of spacer design development was founded. Spacer design based on topology optimization was reconstructed to a simple one considering manufactuability and characteristics of development spacer design. When a simplified design was compared with previous 9 models, new design has a better performance in terms of permeate flux and wall concentration at membrane surface.

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