Salt cleaning of organic-fouled reverse osmosis membranes

Lee, Sangyoup; Elimelech, Menachem

doi:10.1016/j.watres.2006.11.043

Cited by 160 publications

(108 citation statements)

References 26 publications

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“…A number of previous researches have reported that the presence of organic foulants on the membrane surface affects the flow rate due to the chemical composition of the feedwater and the strength of the foulant-foulant interaction [20]. Knowledge of the organic fouling mechanism on the membrane surface can be used as a basis to choose the cleaning procedure.…”

Section: Membrane Rejection and Flow Ratementioning

confidence: 99%

“…Subsequent accumulation of organics on the membrane surface due to convective deposition leads to a fouling layer that makes the hydrophobicity of the membrane surface increase further [26,27]. The fouling layer on the membrane surface can also cause an increase in hydraulic resistance [27] and flow rate decline [20]. The occurrence of fouling on all membranes in this research was attributed to the low flow rate, at an average of 0.4 m 3 /h, and membrane rejection at an average of 70-80% (Figures 7 to 9).…”

Section: Membrane Rejection and Flow Ratementioning

confidence: 99%

“…Previous researches reported that chemical membrane cleaning can already provide almost 100% recovery of membrane flux so it is able to extend membrane lifespan [1,[16][17][18][19][20][21]. The cleaning agents that are usually used are ethylene diamine tetraacetic acid (EDTA) [17,21], alkali solutions like sodium hydroxide (NaOH) [16,18], acid solutions like hydrogen chloride (HCl) [18] and citric acid [16].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Case Study of a Small Scale Reverse Osmosis System for Treatment of Mixed Brackish Water and STP Effluent

Widiasa

Jayanti

2017

J. Eng. Technol. Sci.

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Abstract.A case study on utilizing reverse osmosis (RO) technology to fulfill fresh water needs at a mall and a hotel has been done on Bali Island, Indonesia. A mix of brackish water and sewage treatment plant (STP) effluent was used as feed water in the RO system. The system used 36 membrane elements (CSM RE 8040 BLN) arranged into two stages: 8 pressure vessels (PVs) in the first stage and 4 PVs in the second stage, each loaded with 3 membranes. The objectives of this research were to assess the cleaning effectivity in the plant, to evaluate the cleaning of 1 membrane element using a CIP system, and to assess the use of the membrane for filtration in the pre-treatment system. SEM and FTIR analysis indicated that the foulants on the membrane surface were dominated by organic foulants and inorganic deposits. To clean the discarded membrane the proposed method used NaOH solution (pH 12 and pH 13) and citric acid (pH 2 and pH 3). All membranes displayed a dramatic decline in rejection of about 80%. Based on the rejection tests of SO 4 2-, Cl -, turbidity reduction approached 100%. It can be concluded that an RO membrane that has undergone selectivity decline can be re-used as a filtration membrane in the pre-treatment system.

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Section: Membrane Rejection and Flow Ratementioning

confidence: 99%

Section: Membrane Rejection and Flow Ratementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Case Study of a Small Scale Reverse Osmosis System for Treatment of Mixed Brackish Water and STP Effluent

Widiasa

Jayanti

2017

J. Eng. Technol. Sci.

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“…In addition, these conventional cleaning agents cause a negative environmental impact when they are discharged as wastewaters after the cleaning step. For all these reasons, new alternative cleaning techniques, including ultrasounds [15], electromagnetic fields [16] and saline solutions [17] have been developed in the recent years to overcome these problems. Regarding the use of saline solutions, previous studies reported the salting-in and salting-out effect of different cations and anions to increase or decrease, respectively, protein solubility at pH values above and below the isoelectric point of the protein [18,19].…”

Section: Introductionmentioning

confidence: 99%

Destabilization and removal of immobilized enzymes adsorbed onto polyethersulfone ultrafiltration membranes by salt solutions

Corbatón-Báguena

Gugliuzza

Cassano

et al. 2015

Journal of Membrane Science

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ElsevierCorbatón Báguena, MJ.; Cassano, A.; Giorno, L. (2015). Destabilization AbstractIn this work the effectiveness of two saline solutions (NaCl and Na 2 SO 4 ) to clean a permanently hydrophilic polyethersulfone (PESH) ultrafiltration (UF) membrane with a molecular weight cut-off (MWCO) of 30 kDa previously fouled with enzymatic solutions 2 was investigated. The influence of protein concentration in the enzymatic solution during the fouling step and the effect of salt type during the cleaning procedure were studied.The protein aggregation was analysed in solution and onto the membrane surface by using several techniques including Dynamic Light Scattering (DLS), Atomic Force Microscopy (AFM) and Infrared Spectroscopy with Attenuated Total Reflectance (ATR-FTIR). In addition, mechanisms that dominate membrane fouling were studied by fitting some mathematical models (Hermia's models adapted to crossflow filtration, a combined model based on the complete blocking and cake formation equations and a resistance-in-series model) to the experimental data.Fouling results showed that the complete blocking/adsorption on membrane surface was the predominant fouling mechanism. Regarding the cleaning results, higher cleaning efficiency and low residual protein concentration was obtained with NaCl solutions for all the feed solutions tested due to the favourable interaction between Cl -and proteins.

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“…Recently, a high concentration of common salt (NaCl) has been successfully used to prevent fouling (Liberman and Liberman 2005;Liberman et al 2007;Qin et al 2009Qin et al , 2010 as well as clean fouled RO membranes (Lee and Elimelech 2007). Common table salt is not only very cheap but it is readily soluble in water and it forms the major component of seawater itself.…”

Section: Introductionmentioning

confidence: 99%

Inefficacy of osmotic backwash induced by sodium chloride salt solution in controlling SWRO membrane fouling

Farooque

Al-Jeshi²,

Saeed

et al. 2014

Appl Water Sci

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A study was conducted to evaluate the efficacy of osmotic backwash induced by high salt (NaCl) concentration solution on feed side of seawater reverse osmosis (SWRO) membranes, online and offline, in controlling membrane fouling and therefore minimizing/ eliminating the need for chemical cleaning. SWRO membranes were deliberately fouled by feeding seawater from an open intake located on the Arabian Gulf Coast without dosing chemicals. The fouled membranes were subjected to offline cleaning with the salt solution of up to 25 % concentration. Despite the partial removal of foulants from the membrane surface, SWRO membrane performance could not be restored, indicating the ineffectiveness of osmotic backwash in aiding offline salt cleaning. Similarly, online osmotic backwash was found to be not only ineffective in removing foulants from membrane surfaces but actually increased the fouling rate, as indicated by faster fouling rates compared to other cases. Although the driving force required for the osmotic backwash existed, the generated back flow proved to be insufficient to detach foulants from membrane surfaces. During the study period, the average SWRO membrane flux was maintained between 19 and 23 LMH, whereas the average generated back flow flux by high salt concentration solution was only 11 LMH, which was not adequate to remove foulants from membrane surfaces. Moreover, it seems that the membrane configuration as well as inherent microstructure of SWRO membrane places certain constraints on the osmotic backwash process and renders osmotic backwash ineffective in tackling SWRO membrane fouling. Hence, chemical cleaning is essential to restore SWRO membrane performance whenever fouling occurs, and the use of highly concentrated salt solution does not have any significant benefit. Membrane autopsy revealed only an insignificant accumulation of biofouling layer despite the absence of disinfection. However, it was shown that culturable biofilm bacteria species isolated from membranes tolerated exposure to high salt concentrations at pH range of 7-8. In addition, the overall findings of the study indicate that SWRO membranes can be operated in Gulf seawater at a recovery of 30 % without using any chemicals, such as coagulant, disinfectant and antiscalant, for an acceptable period of time without performing membrane cleaning. This is highly likely, if media filters are used in the pretreatment and SWRO membranes are operated at normal flux and recovery ratio.

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Salt cleaning of organic-fouled reverse osmosis membranes

Cited by 160 publications

References 26 publications

Case Study of a Small Scale Reverse Osmosis System for Treatment of Mixed Brackish Water and STP Effluent

Case Study of a Small Scale Reverse Osmosis System for Treatment of Mixed Brackish Water and STP Effluent

Destabilization and removal of immobilized enzymes adsorbed onto polyethersulfone ultrafiltration membranes by salt solutions

Inefficacy of osmotic backwash induced by sodium chloride salt solution in controlling SWRO membrane fouling

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