Membrane fouling and anti-fouling strategies using RO retentate from a municipal water recycling plant as the feed for osmotic power generation

Handle URI:
http://hdl.handle.net/10754/622310
Title:
Membrane fouling and anti-fouling strategies using RO retentate from a municipal water recycling plant as the feed for osmotic power generation
Authors:
Chen, Si Cong; Amy, Gary L.; Chung, Neal Tai-Shung ( 0000-0003-3704-8609 )
Abstract:
RO retentate from a municipal water recycling plant is considered as a potential feed stream for osmotic power generation in this paper. The feasibility of using RO retentate from a municipal water recycling plant was examined from two aspects: (a) the membrane fouling propensity of RO retentate, and (b) the efficacy of anti-fouling strategies. The membranes used in this study were the inner selective thin film composite polyethersulfone (TFC/PES) hollow fiber membranes, which possessed a high water permeability and good mechanical strength. Scaling by phosphate salts was found to be one possible inorganic fouling on the innermost layer of the PES membrane, whereas silica fouling was observed to be the governing fouling on the outmost surface of the PES membrane. Two anti-fouling pretreatments, i.e., pH adjustment and anti-scalant pre-treatment for the feed stream, were studied and found to be straightforward and effective. Using RO retentate at pH 7.2 as the feed and 1 M NaCl as the draw solution, the average power density was 7.3 W/m at 20 bar. The average power density increased to 12.6 W/m by modifying RO retentate with an initial pH value of 5.5 using HCl and to 13.4 W/m by adding 1.1 mM ethylenediaminetetraacetic acid (EDTA). Moreover, the flux recovery of the fouled membranes, without the indicated pretreatments, reached 84.9% using deionized (DI) water flushing and 95.0% using air bubbling under a high crossflow velocity of 23.3 cm/s (Re = 2497) for 30 min. After pretreatment by pH adjustment, the flux recovery increased to 94.6% by DI water flushing and 100.0% by air bubbling. After pretreatment by adding 1.1 mM EDTA into RO retentate, flux was almost fully restored by physical cleaning by DI water flushing and air bubbling. These results provide insight into developing an effective pretreatment by either pH adjustment or EDTA addition before PRO and physical cleaning methods by DI water flushing and air bubbling for membrane used in osmotic power generation.
KAUST Department:
Water Desalination and Reuse Research Center (WDRC)
Citation:
Chen SC, Amy GL, Chung T-S (2016) Membrane fouling and anti-fouling strategies using RO retentate from a municipal water recycling plant as the feed for osmotic power generation. Water Research 88: 144–155. Available: http://dx.doi.org/10.1016/j.watres.2015.10.008.
Publisher:
Elsevier BV
Journal:
Water Research
Issue Date:
25-Oct-2015
DOI:
10.1016/j.watres.2015.10.008
PubMed ID:
26492341
Type:
Article
ISSN:
0043-1354
Sponsors:
This research is supported by the National Research Foundation, Prime Minister's Office, Singapore under its Competitive Research Program (CRP) entitled "Advanced FO Membranes and Membrane Systems for Wastewater Treatment, Water Reuse and Seawater Desalination" (grant numbers: R-279-000-336-281 and R-278-000-339-281) and by the Environment & Water Industry Programme Office (EWI) of the PUB under the project titled "Membrane Development for Osmotic Power Generation, Part 1. Materials Development and Membrane Fabrication" (grant number: R-279-000-381-279). The author, Si Cong Chen, would also thank the NUS Graduate School for Integrative Sciences & Engineering for the financial support of her PhD study. Special tanks will be given to Mr Chun Feng Wan, Dr Tao Cai, and Mr Yong Liu for their help.
Appears in Collections:
Articles; Water Desalination and Reuse Research Center (WDRC)

Full metadata record

DC FieldValue Language
dc.contributor.authorChen, Si Congen
dc.contributor.authorAmy, Gary L.en
dc.contributor.authorChung, Neal Tai-Shungen
dc.date.accessioned2017-01-02T09:08:25Z-
dc.date.available2017-01-02T09:08:25Z-
dc.date.issued2015-10-25en
dc.identifier.citationChen SC, Amy GL, Chung T-S (2016) Membrane fouling and anti-fouling strategies using RO retentate from a municipal water recycling plant as the feed for osmotic power generation. Water Research 88: 144–155. Available: http://dx.doi.org/10.1016/j.watres.2015.10.008.en
dc.identifier.issn0043-1354en
dc.identifier.pmid26492341en
dc.identifier.doi10.1016/j.watres.2015.10.008en
dc.identifier.urihttp://hdl.handle.net/10754/622310-
dc.description.abstractRO retentate from a municipal water recycling plant is considered as a potential feed stream for osmotic power generation in this paper. The feasibility of using RO retentate from a municipal water recycling plant was examined from two aspects: (a) the membrane fouling propensity of RO retentate, and (b) the efficacy of anti-fouling strategies. The membranes used in this study were the inner selective thin film composite polyethersulfone (TFC/PES) hollow fiber membranes, which possessed a high water permeability and good mechanical strength. Scaling by phosphate salts was found to be one possible inorganic fouling on the innermost layer of the PES membrane, whereas silica fouling was observed to be the governing fouling on the outmost surface of the PES membrane. Two anti-fouling pretreatments, i.e., pH adjustment and anti-scalant pre-treatment for the feed stream, were studied and found to be straightforward and effective. Using RO retentate at pH 7.2 as the feed and 1 M NaCl as the draw solution, the average power density was 7.3 W/m at 20 bar. The average power density increased to 12.6 W/m by modifying RO retentate with an initial pH value of 5.5 using HCl and to 13.4 W/m by adding 1.1 mM ethylenediaminetetraacetic acid (EDTA). Moreover, the flux recovery of the fouled membranes, without the indicated pretreatments, reached 84.9% using deionized (DI) water flushing and 95.0% using air bubbling under a high crossflow velocity of 23.3 cm/s (Re = 2497) for 30 min. After pretreatment by pH adjustment, the flux recovery increased to 94.6% by DI water flushing and 100.0% by air bubbling. After pretreatment by adding 1.1 mM EDTA into RO retentate, flux was almost fully restored by physical cleaning by DI water flushing and air bubbling. These results provide insight into developing an effective pretreatment by either pH adjustment or EDTA addition before PRO and physical cleaning methods by DI water flushing and air bubbling for membrane used in osmotic power generation.en
dc.description.sponsorshipThis research is supported by the National Research Foundation, Prime Minister's Office, Singapore under its Competitive Research Program (CRP) entitled "Advanced FO Membranes and Membrane Systems for Wastewater Treatment, Water Reuse and Seawater Desalination" (grant numbers: R-279-000-336-281 and R-278-000-339-281) and by the Environment & Water Industry Programme Office (EWI) of the PUB under the project titled "Membrane Development for Osmotic Power Generation, Part 1. Materials Development and Membrane Fabrication" (grant number: R-279-000-381-279). The author, Si Cong Chen, would also thank the NUS Graduate School for Integrative Sciences & Engineering for the financial support of her PhD study. Special tanks will be given to Mr Chun Feng Wan, Dr Tao Cai, and Mr Yong Liu for their help.en
dc.publisherElsevier BVen
dc.subjectAnti-foulingen
dc.subjectFoulingen
dc.subjectOsmotic power generationen
dc.subjectPhosphateen
dc.subjectPressure retarded osmosisen
dc.subjectSilicaen
dc.titleMembrane fouling and anti-fouling strategies using RO retentate from a municipal water recycling plant as the feed for osmotic power generationen
dc.typeArticleen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.identifier.journalWater Researchen
dc.contributor.institutionNUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore, 28 Medical Drive, Singapore, 117456, Singaporeen
dc.contributor.institutionDepartment of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singaporeen
kaust.authorAmy, Gary L.en
kaust.authorChung, Neal Tai-Shungen
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