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Control of Biofouling in Membrane Bioreactor for Wastewater Treatment by Quorum-Quenching Bacteria Immobilized in Moving Beads : 정족수감지 억제 세균이 고정화된 유동성 담체를 이용한 하폐수 처리용 분리막 생물반응기에서의 생물막오염 제어
| DC Field | Value | Language |
|---|---|---|
| dc.contributor.advisor | 김재정 | - |
| dc.contributor.author | 김상룡 | - |
| dc.date.accessioned | 2018-11-12T00:55:01Z | - |
| dc.date.available | 2018-11-12T00:55:01Z | - |
| dc.date.issued | 2018-08 | - |
| dc.identifier.other | 000000151655 | - |
| dc.identifier.uri | https://hdl.handle.net/10371/143047 | - |
| dc.description | 학위논문 (박사)-- 서울대학교 대학원 : 공과대학 화학생물공학부, 2018. 8. 김재정. | - |
| dc.description.abstract | Membrane bioreactor (MBR) is a widely used as an advanced wastewater treatment process, but membrane biofouling is a chronic problem. Recently quorum quenching (QQ) technology has attracted attention as a new solution to suppress biofouling. The purpose of this study is to develop a moving carrier capable of simultaneously anticipating both the physical cleaning and the quorum sensing inhibition to prevent more effective biofouling.
Rhodococcus sp. BH4, known as QQ bacteria, was immobilized on a calcium-alginate matrix and developed a new membrane fouling inhibitor, freely moving bead, called a cell entrapping beads (CEBs). Because CEB has a specific gravity similar to water, it moves freely by aeration, generates physical cleaning effect by colliding with the membrane as well as effectively suppresses QS mechanism by using QQ. Especially, when the QS of membrane fouling microorganisms is disturbed, extracellular polymeric substances (EPS) production is slowed, and loosely bound biofilm is formed. Therefore, the physical cleaning effect of CEB synergistically increased with the QQ effect. Through this combined effect, CEB delayed membrane biofouling by 8 times slower than conventional MBR in a continuous process. As the following study, improvement of the physical and chemical stability of the CEB have conducted to the application for actual MBR processes. The first is a fluid coating carrier (Macrocapsule), which surrounds CEB with porous membrane using a non-solvent induced phase separation technique. The porous membrane was formed on the surface by a spontaneous phase inversion between the amphipathic polymer solution and the contained water in CEB. Macrocapsule showed excellent biofilm control effect for 80 days on laboratory scale continuous MBR process and retained its QQ activity. The second is W-bead, which is prepared by double cross-linking with polyvinyl alcohol and alginate. The W-bead showed excellent stability and biofouling mitigation effect in the MBR fed with real wastewater. This study suggests the free-moving beads as an efficient QQ bacteria carrier and showed potential for actual MBR application. | - |
| dc.description.tableofcontents | Table of Contents
Abstract ....................................................................................... iii List of Figures .............................................................................. x List of Tables .......................................................................... xviii I. Introduction .............................................................................. 1 I.1. Backgrounds ...................................................................................... 3 I.2. Objectives ........................................................................................... 4 II. Literature Review ................................................................... 5 II.1. MBR for Advanced Wastewater Treatment .................................... 7 II.1.1. Concept and Process ................................................................... 7 II.1.2. Development of MBR ................................................................. 9 II.1.3. Trends in MBR: Market and Research ................................... 13 II.1.4. Fouling Control in MBR Systems ............................................ 19 II.1.5. Biofilm in MBR ......................................................................... 25 II.2. Quorum Sensing (QS) Signaling in Bacteria ................................. 29 II.2.1. Definition and Mechanism ....................................................... 29 II.2.2. Gram-Negative Bacteria with AHLs: Type AI-1 System ....... 31 II.2.3. Gram-Positive Bacteria with AIPs .......................................... 38 II.2.4. Interspecies Communication: Type AI-2 System ................... 39 II.2.5. Other QS Systems ..................................................................... 41 II.2.6. QS Regulated Biofilm Formation ............................................ 42 II.3. QS Control Strategy ........................................................................ 44 II.3.1. Three-Point of QS Inhibition Strategies ................................. 44 II.3.2. Quorum Sensing Inhibitor (QSI) for AI-1 Regulation .......... 45 II.3.3. Reporter Strain to Detect QS Signal and Screening QSI ...... 49 II.4. Immobilization Technique for Biocatalyst..................................... 52 II.4.1. Enzyme Immobilization Method ............................................. 53 II.4.2. Nanobiocatalysis ....................................................................... 58 II.4.3. Whole-Cell Immobilization Method ........................................ 59 II.4.4. Industrial Application Using Immobilization Technique ..... 62 II.5. Quorum Quenching (QQ) Application to MBR ............................ 64 II.5.1. Enzymatic QQ Application to MBR ........................................ 65 II.5.2. Bacteria Strains with QQ Enzyme .......................................... 66 II.5.3. Bacterial QQ Application to MBR .......................................... 68 II.5.4. Microbial Ecology in MBR ...................................................... 70 III. Control of Membrane Biofouling in MBR by QQ Bacteria Entrapping Alginate Beads ................................... 73 III.1. Introduction ..................................................................................... 75 III.2. Experimental Section ...................................................................... 76 III.2.1. Bioassay for Detecting AHL Molecules ................................... 76 III.2.2. Preparation of Cell Entrapping Beads (CEBs) ...................... 77 III.2.3. Measurement of QQ Activity ................................................... 78 III.2.4. Extraction and Analysis of AHLs using High-Pressure Liquid Chromatography (HPLC) ........................................................ 79 III.2.5. MBR Operation ........................................................................ 80 III.2.6. Measurement of Loosely and Tightly Bound Biofilms .......... 82 III.2.7. Straining of CEBs Image Analysis Using a Confocal Laser Scanning Microscope (CLSM) ................................................. 84 III.2.8. Analytical Methods ................................................................... 84 III.3. Results and Discussion .................................................................... 84 III.3.1. Characterization of CEBs. ....................................................... 84 III.3.2. QQ Activity of Free BH4 and CEBs ........................................ 87 III.3.3. Application of CEBs to the Lab-Scale MBR. ......................... 88 III.3.4. Physical Washing Effect of CEBs ............................................ 90 III.3.5. QQ Effect of CEBs. ................................................................... 92 III.3.6. Inhibition of EPS Production by CEBs ................................... 93 III.3.7. Identification of Signal Molecules in MBRs ........................... 95 III.3.8. Visual Confirmation of the QQ Effect by CEBs .................... 98 III.3.9. Influence of CEBs on MBR Performance and Its Stability .. 99 III.4. Conclusions .................................................................................... 101 IV. Stability Enhancement of QQ Bacteria Entrapping Moving Bead and Its Application to MBR for Biofouling Control .................................................................................. 103 IV.1. Introduction ................................................................................... 105 IV.2. Experimental Section .................................................................... 106 IV.2.1. Microorganisms and Growth Conditions ............................. 106 IV.2.2. Preparation of Macrocapsules and W-beads ........................ 106 IV.2.3. Luminescence Method for Detecting AHL Molecules ......... 108 IV.2.4. Determination of QQ Activity ................................................ 109 IV.2.5. Measurement of Mechanical Strength .................................. 110 IV.2.6. Measurement of Chemical Stability (Macrocapsule) .......... 110 IV.2.7. Restoration of QQ Activity of Disintegrated Beads ............. 111 IV.2.8. Measurement of Durability in Wastewater (W-bead) ......... 111 IV.2.9. MBR Operation Condition .................................................... 111 IV.2.10. Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM)............................................... 113 IV.3. Results and Discussion .................................................................. 113 IV.3.1. Preparation and Characterization of Macrocapsules with Various Polymeric Coatings ................................................... 113 IV.3.2. Characteristics of W-bead ...................................................... 117 IV.3.3. QQ Activities of PSf-Macrocapsules ..................................... 119 IV.3.4. QQ Activities of W-beads ....................................................... 122 IV.3.5. Stability of Macrocapsule in a Harsh Environment ............ 123 IV.3.6. Biofouling Inhibition by Macrocapsules in a Continuous MBR Fed with Synthetic Wastewater ................................... 126 IV.3.7. Biofouling Inhibition by Macrocapsules in a Continuous MBR Fed with Real Wastewater ........................................... 129 IV.3.8. Biofouling Inhibition by W-bead in a Continuous MBR ..... 134 IV.3.9. Stability of W-bead in Various Wastewater .......................... 137 IV.4. Conclusions .................................................................................... 139 V. Conclusions .......................................................................... 141 VI. Suggestions..…..…….……………………………………145 | - |
| dc.language.iso | en | - |
| dc.publisher | 서울대학교 대학원 | - |
| dc.subject.ddc | 660.6 | - |
| dc.title | Control of Biofouling in Membrane Bioreactor for Wastewater Treatment by Quorum-Quenching Bacteria Immobilized in Moving Beads | - |
| dc.title.alternative | 정족수감지 억제 세균이 고정화된 유동성 담체를 이용한 하폐수 처리용 분리막 생물반응기에서의 생물막오염 제어 | - |
| dc.type | Thesis | - |
| dc.contributor.AlternativeAuthor | Sang-Ryoung Kim | - |
| dc.description.degree | Doctor | - |
| dc.contributor.affiliation | 공과대학 화학생물공학부 | - |
| dc.date.awarded | 2018-08 | - |
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