Cleaning protocol for a FO membrane fouled in wastewater reuse

Handle URI:
http://hdl.handle.net/10754/562774
Title:
Cleaning protocol for a FO membrane fouled in wastewater reuse
Authors:
Valladares Linares, Rodrigo ( 0000-0003-3790-3249 ) ; Li, Zhenyu; Yangali-Quintanilla, Victor; Li, Qingyu; Amy, Gary L.
Abstract:
Forward osmosis (FO) is an emerging technology which can be applied in water reuse applications. Osmosis is a natural process that involves less energy consumption than reverse osmosis (RO), and therefore can be applied as a dilution process before low-pressure RO; it is expected to compete favourably against current advanced water reuse technologies that use microfiltration/ultrafiltration and RO. The focus of this research was to assess the efficiency of different cleaning procedures to remove fouling from the surface of a FO membrane during the operation of a submerged system working in FO-mode (active layer (AL) facing feed solution) intended for secondary wastewater effluent (SWWE) recovery, using seawater as draw solution (DS), which will be diluted and can further be fed to a low-pressure RO unit to produce fresh water. Natural organic matter (NOM) fouling was expected to affect the AL, while for the support layer (SL), transparent exopolymer particles (TEP) were used as indicators of fouling due to their stickiness and propensity to enhance the attachment of other foulants in seawater on the membrane surface. The composition of the NOM fouling layer was determined after proper characterisation with a liquid chromatograph coupled with organic carbon detection (LC-OCD), showing biopolymers and protein-like substances as the main constituents. NOM fouling showed high hydraulic reversibility after a 25% flux decline was observed, up to 89.5% when in situ air scouring for 15 min was used as a cleaning technique. Chemical cleaning with a mixture of Alconox, an industrial detergent containing phosphates, and sodium EDTA showed to increase the reversibility (93.6%). Osmotic backwash using a 4% NaCl solution and DI water proved to be ineffective to recover flux due to the salt diffusion phenomena occurring at the AL. Part of the flux that could not be recovered is attributable to TEP fouling on the SL, which forms clusters clearly identifiable with an optical microscope and TEP-specific dyeing/staining of the membrane. Two solutions were tested to clean in place of the SL: a 1% NaOCl solution and the same detergent solution used to clean the AL. The former agent compromised the integrity of the FO membrane, as proved with flux and conductivity measurements; 94.5% of flux was recovered with the latter agent, showing that chemically irreversible fouling for the FO membrane is on the order of 5.5%, which might be associated with the adsorption of biopolymers on the AL and some TEP residuals on the SL. Physical cleaning (air scouring) of the AL proved to be the most effective way to control fouling. © 2013 Copyright Balaban Desalination Publications.
KAUST Department:
Water Desalination and Reuse Research Center (WDRC); Water Desalination and Reuse Research Center; Biological and Environmental Sciences and Engineering (BESE) Division; Environmental Science and Engineering Program
Publisher:
Taylor & Francis
Journal:
Desalination and Water Treatment
Issue Date:
30-May-2013
DOI:
10.1080/19443994.2013.795345
Type:
Article
ISSN:
19443994
Appears in Collections:
Articles; Environmental Science and Engineering Program; Water Desalination and Reuse Research Center (WDRC); Biological and Environmental Sciences and Engineering (BESE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorValladares Linares, Rodrigoen
dc.contributor.authorLi, Zhenyuen
dc.contributor.authorYangali-Quintanilla, Victoren
dc.contributor.authorLi, Qingyuen
dc.contributor.authorAmy, Gary L.en
dc.date.accessioned2015-08-03T11:05:14Zen
dc.date.available2015-08-03T11:05:14Zen
dc.date.issued2013-05-30en
dc.identifier.issn19443994en
dc.identifier.doi10.1080/19443994.2013.795345en
dc.identifier.urihttp://hdl.handle.net/10754/562774en
dc.description.abstractForward osmosis (FO) is an emerging technology which can be applied in water reuse applications. Osmosis is a natural process that involves less energy consumption than reverse osmosis (RO), and therefore can be applied as a dilution process before low-pressure RO; it is expected to compete favourably against current advanced water reuse technologies that use microfiltration/ultrafiltration and RO. The focus of this research was to assess the efficiency of different cleaning procedures to remove fouling from the surface of a FO membrane during the operation of a submerged system working in FO-mode (active layer (AL) facing feed solution) intended for secondary wastewater effluent (SWWE) recovery, using seawater as draw solution (DS), which will be diluted and can further be fed to a low-pressure RO unit to produce fresh water. Natural organic matter (NOM) fouling was expected to affect the AL, while for the support layer (SL), transparent exopolymer particles (TEP) were used as indicators of fouling due to their stickiness and propensity to enhance the attachment of other foulants in seawater on the membrane surface. The composition of the NOM fouling layer was determined after proper characterisation with a liquid chromatograph coupled with organic carbon detection (LC-OCD), showing biopolymers and protein-like substances as the main constituents. NOM fouling showed high hydraulic reversibility after a 25% flux decline was observed, up to 89.5% when in situ air scouring for 15 min was used as a cleaning technique. Chemical cleaning with a mixture of Alconox, an industrial detergent containing phosphates, and sodium EDTA showed to increase the reversibility (93.6%). Osmotic backwash using a 4% NaCl solution and DI water proved to be ineffective to recover flux due to the salt diffusion phenomena occurring at the AL. Part of the flux that could not be recovered is attributable to TEP fouling on the SL, which forms clusters clearly identifiable with an optical microscope and TEP-specific dyeing/staining of the membrane. Two solutions were tested to clean in place of the SL: a 1% NaOCl solution and the same detergent solution used to clean the AL. The former agent compromised the integrity of the FO membrane, as proved with flux and conductivity measurements; 94.5% of flux was recovered with the latter agent, showing that chemically irreversible fouling for the FO membrane is on the order of 5.5%, which might be associated with the adsorption of biopolymers on the AL and some TEP residuals on the SL. Physical cleaning (air scouring) of the AL proved to be the most effective way to control fouling. © 2013 Copyright Balaban Desalination Publications.en
dc.publisherTaylor & Francisen
dc.subjectCleaningen
dc.subjectForward osmosisen
dc.subjectFoulingen
dc.subjectNatural organic matteren
dc.subjectTransparent exopolymer particlesen
dc.titleCleaning protocol for a FO membrane fouled in wastewater reuseen
dc.typeArticleen
dc.contributor.departmentWater Desalination and Reuse Research Center (WDRC)en
dc.contributor.departmentWater Desalination and Reuse Research Centeren
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
dc.contributor.departmentEnvironmental Science and Engineering Programen
dc.identifier.journalDesalination and Water Treatmenten
dc.contributor.institutionGRUNDFOS Management A/S, Poul Due Jensens Vej 7, DK-8850 Bjerringbro, Denmarken
kaust.authorValladares Linares, Rodrigoen
kaust.authorLi, Zhenyuen
kaust.authorYangali-Quintanilla, Victoren
kaust.authorLi, Qingyuen
kaust.authorAmy, Gary L.en
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