Biofouling investigation in membrane filtration systems using Optical Coherence Tomography (OCT)

Handle URI:
http://hdl.handle.net/10754/625949
Title:
Biofouling investigation in membrane filtration systems using Optical Coherence Tomography (OCT)
Authors:
Fortunato, Luca ( 0000-0002-0969-1296 )
Abstract:
Biofouling represents the main problem in membrane filtration systems. Biofouling arises when the biomass growth negatively impacts the membrane performance parameters (i.e. flux decrease and feed channel pressure drop). Most of the available techniques for characterization of biofouling involve membrane autopsies, providing information ex-situ destructively at the end of the process. OCT, is non-invasive imaging technique, able to acquire scans in-situ and non-destructively. The objective of this study was to evaluate the suitability of OCT as in-situ and non-destructive tool to gain a better understanding of biofouling behavior in membrane filtration systems. The OCT was employed to study the fouling behavior in two different membrane configurations: (i) submerged flat sheet membrane and (ii) spacer filled channel. Through the on-line acquisition of OCT scans and the study of the biomass morphology, it was possible to relate the impact of the fouling on the membrane performance. The on-line monitoring of biofilm formation on a flat sheet membrane was conducted in a gravity-driven submerged membrane bioreactor (SMBR) for 43 d. Four different phases were observed linking the variations in permeate flux with changes in biofilm morphology. Furthermore, the biofilm morphology was used in computational fluid dynamics (CFD) simulation to better understand the role of biofilm structure on the filtration mechanisms. The time-resolved OCT analysis was employed to study the biofouling development at the early stage. Membrane coverage and average biofouling layer thickness were found to be linearly correlated with the permeate flux pattern. An integrated characterization methodology was employed to characterize the fouling on a flat sheet membrane, involving the use of OCT as first step followed by membrane autopsies, revealing the presence of a homogeneous layer on the surface. In a spacer filled channel a 3D OCT time series analysis of biomass development under representative conditions for a spiral-wound membrane element was performed. Biomass accumulation was stronger on the feed spacer during the early stage, impacting the feed channel pressure drop more than the permeate flux. OCT biofilm thickness map was presented as new tool to evaluate the biofouling development in membrane filtration systems through the use of a false color scale.
Advisors:
Leiknes, TorOve ( 0000-0003-4046-5622 )
Committee Member:
Heidrich, Wolfgang ( 0000-0002-4227-8508 ) ; Saikaly, Pascal ( 0000-0001-7678-3986 ) ; Vigneswaran, Saravanamuthu
KAUST Department:
Biological and Environmental Sciences and Engineering (BESE) Division
Program:
Environmental Science and Engineering
Issue Date:
Oct-2017
Type:
Dissertation
Appears in Collections:
Dissertations

Full metadata record

DC FieldValue Language
dc.contributor.advisorLeiknes, TorOveen
dc.contributor.authorFortunato, Lucaen
dc.date.accessioned2017-10-29T05:47:18Z-
dc.date.available2017-10-29T05:47:18Z-
dc.date.issued2017-10-
dc.identifier.urihttp://hdl.handle.net/10754/625949-
dc.description.abstractBiofouling represents the main problem in membrane filtration systems. Biofouling arises when the biomass growth negatively impacts the membrane performance parameters (i.e. flux decrease and feed channel pressure drop). Most of the available techniques for characterization of biofouling involve membrane autopsies, providing information ex-situ destructively at the end of the process. OCT, is non-invasive imaging technique, able to acquire scans in-situ and non-destructively. The objective of this study was to evaluate the suitability of OCT as in-situ and non-destructive tool to gain a better understanding of biofouling behavior in membrane filtration systems. The OCT was employed to study the fouling behavior in two different membrane configurations: (i) submerged flat sheet membrane and (ii) spacer filled channel. Through the on-line acquisition of OCT scans and the study of the biomass morphology, it was possible to relate the impact of the fouling on the membrane performance. The on-line monitoring of biofilm formation on a flat sheet membrane was conducted in a gravity-driven submerged membrane bioreactor (SMBR) for 43 d. Four different phases were observed linking the variations in permeate flux with changes in biofilm morphology. Furthermore, the biofilm morphology was used in computational fluid dynamics (CFD) simulation to better understand the role of biofilm structure on the filtration mechanisms. The time-resolved OCT analysis was employed to study the biofouling development at the early stage. Membrane coverage and average biofouling layer thickness were found to be linearly correlated with the permeate flux pattern. An integrated characterization methodology was employed to characterize the fouling on a flat sheet membrane, involving the use of OCT as first step followed by membrane autopsies, revealing the presence of a homogeneous layer on the surface. In a spacer filled channel a 3D OCT time series analysis of biomass development under representative conditions for a spiral-wound membrane element was performed. Biomass accumulation was stronger on the feed spacer during the early stage, impacting the feed channel pressure drop more than the permeate flux. OCT biofilm thickness map was presented as new tool to evaluate the biofouling development in membrane filtration systems through the use of a false color scale.en
dc.language.isoenen
dc.subjectBiofoulingen
dc.subjectDesalinationen
dc.subjectOCTen
dc.subjectBiofilmen
dc.subjectFoulingen
dc.subjectMembraneen
dc.titleBiofouling investigation in membrane filtration systems using Optical Coherence Tomography (OCT)en
dc.typeDissertationen
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
thesis.degree.grantorKing Abdullah University of Science and Technologyen
dc.contributor.committeememberHeidrich, Wolfgangen
dc.contributor.committeememberSaikaly, Pascalen
dc.contributor.committeememberVigneswaran, Saravanamuthuen
thesis.degree.disciplineEnvironmental Science and Engineeringen
thesis.degree.nameDoctor of Philosophyen
dc.person.id123597en
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