Effect on backwash cleaning efficiency with TDS concentrations of circulated water and backwashing water in SWRO membrane

Nam, Jong Woo; Park, Jun Yong; Kim, Ji Hoon; Lee, Yong Soo; Lee, Eui Jong; Jeon, Min Jung; Kim, Hyung Soo; Jang, Am

doi:10.1080/19443994.2012.672162

Cited by 16 publications

(3 citation statements)

References 14 publications

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“…Osmotic backwashing is a typical membrane backwashing approach used for cleaning the fouled FO/PRO membranes. It is originally developed from the RO desalination industry to mitigate RO membrane fouling [260][261][262][263][264][265][266][267]. With the development of FO/PRO technology, it has been extensively used for FO/PRO membrane cleaning [10,23,33,35,37,127,194,268,269].…”

Section: Physical Cleaningmentioning

confidence: 99%

Membrane fouling in osmotically driven membrane processes: A review

She

Wang

Fane

et al. 2016

Journal of Membrane Science

722

373

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Section: Physical Cleaningmentioning

confidence: 99%

Membrane fouling in osmotically driven membrane processes: A review

She

Wang

Fane

et al. 2016

Journal of Membrane Science

722

373

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“…To clean a fouled membrane, chemical cleaning is conducted once every few months [46,51,52]. The frequency of chemical cleaning is determined by the normalized performance of the RO membranes [46].…”

Section: Introductionmentioning

confidence: 99%

How RO membrane permeability and other performance factors affect process cost and energy use: A review

2019

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Reverse osmosis (RO) technology has progressed steadily over the last few decades. Those gains were achieved through improvements in both RO membrane element performance and energy recovery technologies. However, some recent literature indicates that RO membrane water permeability is approaching performance limits imposed by transport processes and thermodynamic constraints. This paper reviews how RO membrane element performance affects the cost of RO processes, especially the specific energy consumption. RO membrane performance encompasses water permeability, salt permeability, and other some characteristics of the RO element. This paper considers not only conventional RO processes, but also the recently proposed closed-circuit RO and batch RO processes. Even if the membrane water permeability increases, little additional effect is found when the membrane water permeability exceeds around 3 LMH/bar for seawater RO and 8 LMH/bar for brackish water RO in conventional single-stage RO. Increasing membrane water permeability has the potential to decrease membrane surface area and associated costs. A major limitation of most existing literature is that performance is evaluation on in terms of the initial operating conditions. Chronological changes, such as result from fouling, must also be considered to accurately validate how membrane element performance affects RO cost.

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“…A wide range in osmotic backwashing duration has been adopted in the literature, from an injection lasting 50 to 60 seconds [17], to 10 minutes [19], and even up to 1 hour [23]. The cleaning duration should be optimized, as after a certain amount of cleaning time, osmotic backwashing flux ceases [24][25][26][27]. Furthermore, cleaning duration should be maintained as short as possible in order to reduce time lost due to cleaning, as well as reduce the amount of osmotic backwashing solution needed, but always ensuring cleaning efficiency.…”

Section: Introductionmentioning

confidence: 99%

Influence of organic fouling layer characteristics and osmotic backwashing conditions on cleaning efficiency of RO membranes

Daly

Allen

Koutsos

et al. 2020

Journal of Membrane Science

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Fouling remains a prevalent and serious problem in industries using membrane processes.Efforts to mitigate fouling are improving, however, membrane fouling cannot be completely eliminated. Therefore fouling control via development of sustainable cleaning methods are crucial. Despite osmotic backwashing showing promise, little is understood about this cleaning method for removal of fouling from reverse osmosis (RO) membranes. This paper systematically examines how organic fouling characteristics and osmotic backwashing parameters influence cleaning efficiency. Alginic acid was used as a model foulant and numerous microscopy techniques, including confocal microscopy, scanning electron microscopy and atomic force microscopy were used to examine the membrane fouling before and after cleaning to gain a clearer understanding of the mechanisms involved. Increasing CaCl2 concentration in the fouling solution resulted in an increase in fouling layer thickness from 37 to 179 µm, due to the complexation of Ca 2+ and the carboxyl groups in the alginate.Osmotic backwashing efficiency with 0.7 M NaCl decreased as the fouling layer became thicker and the pure water flux (PWF) recovery decreased from 92% to 81%. Osmotic backwashing efficiency also decreased with increasing initial permeate flux, as less fouling was removed: the fouling generated at higher initial fluxes is largely irreversible, resulting in a denser and more compact fouling layer. In an effort to increase osmotic backwashing flux, a CaCl2 draw solution was used, however, the Ca 2+ ions were found to interact with the alginate in the fouling layer, rendering this method inefficient, when compared to NaCl draw solutions which originated similar osmotic backwashing fluxes. Interestingly, the fouling layer was found to swell from 16 µm to 141 µm, when osmotic backwashing was carried out with a NaCl draw solution, followed by contact with a low ionic strength solution used for PWF testing. This phenomenon does not occur to the same extent after backwashing with CaCl2. The same trends were obtained for bovine serum albumin (BSA) fouling, whilst humic acid (HA) did not display any swelling phenomena. However, it showed the same cleaning inefficiency when using CaCl2 as a draw solution.

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Effect on backwash cleaning efficiency with TDS concentrations of circulated water and backwashing water in SWRO membrane

Cited by 16 publications

References 14 publications

Membrane fouling in osmotically driven membrane processes: A review

Membrane fouling in osmotically driven membrane processes: A review

How RO membrane permeability and other performance factors affect process cost and energy use: A review

Influence of organic fouling layer characteristics and osmotic backwashing conditions on cleaning efficiency of RO membranes

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