Advanced Monitoring and Characterization of Biofouling in Gravity-driven Membrane Filtration

Handle URI:
http://hdl.handle.net/10754/609159
Title:
Advanced Monitoring and Characterization of Biofouling in Gravity-driven Membrane Filtration
Authors:
Wang, Yiran ( 0000-0002-9062-4751 )
Abstract:
Gravity-driven membrane (GDM) filtration is one of the promising membrane bioreactor (MBR) technologies. It operates at a low pressure by gravity, requiring a minimal energy. Thus, it exhibits a great potential for a decentralized system, conducting household in developing and transition countries. Biofouling is a universal problem in almost all membrane filtration applications, leading to the decrease in flux or the increase in transmembrane pressure depending on different operation mode. Air scoring or regular membrane cleaning has been utilized for fouling mitigation, which requires increased energy consumption as well as complicated operations. Besides, repeating cleaning will trigger the deterioration of membranes and shorten their lifetime, elevating cost expenditures accordingly. In this way, GDM filtration stands out from conventional MBR technologies in a long-term operation with relative stable flux, which has been observed in many studies. The objective of this study was to monitor the biofilm development on a flat sheet membrane submerged in a GDM reactor with constant gravitational pressure. Morphology of biofilm layer in a fixed position was acquired by an in-situ and on-line OCT (optical coherence tomography) scanning at regular intervals for both visual investigation and structure analysis. The calculated thickness and roughness were compared to the variation of flux, fouling resistance and permeate quality, showing expected consistency. At the end of experiment, the morphology of entire membrane surface was scanned and recorded by OCT. Membrane autopsy was carried out for biofilm composition analysis by total organic carbon (TOC) and liquid chromatography with organic carbon detection (LC-OCD). In addition, biomass concentration was obtained by flow cytometer and adenosine tri-phosphate (ATP) method. The data of biofilm components indicated a homogeneous biofilm structure formed after a long-term running of the GDM system, based on the morphology observation by OCT images. The superiority of GDM in both flux maintaining and long-term operation with production of high quality effluent was demonstrated, as well as the suitability of OCT for biofouling monitoring was emphasized.
Advisors:
Leiknes, TorOve ( 0000-0003-4046-5622 )
Committee Member:
Saikaly, Pascal ( 0000-0001-7678-3986 ) ; Wei, Chun-Hai
KAUST Department:
Biological and Environmental Sciences and Engineering (BESE) Division; Environmental Science and Engineering Program
Program:
Environmental Science and Engineering
Issue Date:
May-2016
Type:
Thesis
Appears in Collections:
Environmental Science and Engineering Program; Theses; Biological and Environmental Sciences and Engineering (BESE) Division

Full metadata record

DC FieldValue Language
dc.contributor.advisorLeiknes, TorOveen
dc.contributor.authorWang, Yiranen
dc.date.accessioned2016-05-12T11:59:06Zen
dc.date.available2016-05-12T11:59:06Zen
dc.date.issued2016-05en
dc.identifier.urihttp://hdl.handle.net/10754/609159en
dc.description.abstractGravity-driven membrane (GDM) filtration is one of the promising membrane bioreactor (MBR) technologies. It operates at a low pressure by gravity, requiring a minimal energy. Thus, it exhibits a great potential for a decentralized system, conducting household in developing and transition countries. Biofouling is a universal problem in almost all membrane filtration applications, leading to the decrease in flux or the increase in transmembrane pressure depending on different operation mode. Air scoring or regular membrane cleaning has been utilized for fouling mitigation, which requires increased energy consumption as well as complicated operations. Besides, repeating cleaning will trigger the deterioration of membranes and shorten their lifetime, elevating cost expenditures accordingly. In this way, GDM filtration stands out from conventional MBR technologies in a long-term operation with relative stable flux, which has been observed in many studies. The objective of this study was to monitor the biofilm development on a flat sheet membrane submerged in a GDM reactor with constant gravitational pressure. Morphology of biofilm layer in a fixed position was acquired by an in-situ and on-line OCT (optical coherence tomography) scanning at regular intervals for both visual investigation and structure analysis. The calculated thickness and roughness were compared to the variation of flux, fouling resistance and permeate quality, showing expected consistency. At the end of experiment, the morphology of entire membrane surface was scanned and recorded by OCT. Membrane autopsy was carried out for biofilm composition analysis by total organic carbon (TOC) and liquid chromatography with organic carbon detection (LC-OCD). In addition, biomass concentration was obtained by flow cytometer and adenosine tri-phosphate (ATP) method. The data of biofilm components indicated a homogeneous biofilm structure formed after a long-term running of the GDM system, based on the morphology observation by OCT images. The superiority of GDM in both flux maintaining and long-term operation with production of high quality effluent was demonstrated, as well as the suitability of OCT for biofouling monitoring was emphasized.en
dc.language.isoenen
dc.subjectgravity-driven membrane filtrationen
dc.subjectUF Membraneen
dc.subjectBiofoulingen
dc.subjectSubmerged Systemen
dc.subjectOptical coherence tomographyen
dc.titleAdvanced Monitoring and Characterization of Biofouling in Gravity-driven Membrane Filtrationen
dc.typeThesisen
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
dc.contributor.departmentEnvironmental Science and Engineering Programen
thesis.degree.grantorKing Abdullah University of Science and Technologyen_GB
dc.contributor.committeememberSaikaly, Pascalen
dc.contributor.committeememberWei, Chun-Haien
thesis.degree.disciplineEnvironmental Science and Engineeringen
thesis.degree.nameMaster of Scienceen
dc.person.id133278en
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