Dewatering of activated sludge by forward osmosis (FO) with ultrasound (US) for fouling control
- 주제(키워드) activated sludge , dewatering , forward osmosis , membrane fouling , ultrasound
- 발행기관 고려대학교 대학원
- 지도교수 홍승관
- 발행년도 2016
- 학위수여년월 2016. 8
- 학위구분 석사
- 학과 대학원 건축사회환경공학과
- 세부전공 물과 환경
- 원문페이지 94 p
- 실제URI http://www.dcollection.net/handler/korea/000000068381
- 본문언어 영어
- 제출원본 000045881421
초록/요약
The high mass of feed contents and the complexity of compounds including organic matters, inorganic ions, microbes, trace contaminants, and toxic chemicals makes wastewaters difficult to treat. FO dewatering of wastewaters can recover and curtail the volume of final effluent dumping into the environment, therefore, it makes wastewaters more disposable. FO has been extensively researched due to promising advantages including high rejection and low fouling propensity. FO maintains a great possibility to deal with wastewater, such as food concentrate, oil produced water, and municipal wastewater, which has high fouling propensity. FO presents high level of rejection and separates dissolved solids from high concentration solutions by its small pore radius, therefore, permeated water keeps high quality without unwanted ions and solids. Notwithstanding the great appeal of FO process, its performance can be altered by membrane fouling. Feed solutions that are employed in the dewatering process are mostly having high level of substances and complex constituents which caused the deposition of particles, colloids, microbes, organic macro-molecules, soluble inorganic matters. As a means to resolve this issue, establishing more effective strategies to alleviate fouling has been studied by a number of researchers. Feed streams are pretreated to lessen membrane fouling by controlling feed water chemistry or separating foulants. Optimization of operation factors such as membrane orientation, cross-flow velocity, and operating pressure is holding a significant impact for the mitigation of fouling. Reformation of membrane properties can considerably affect the membrane fouling. Reducing surface charge density, increasing surface hydrophilicity, incorporation nano materials, and decreasing surface roughness are confirmed as effective modification for fouling control. Membrane cleaning such as surface flushing and backwashing have been extensively used to diminish membrane fouling in FO dewatering. In this study, the implications of ultrasound on fouling by activated sludge flocs was studied and, as a novel membrane cleaning, ultrasound and combination of ultrasound and flushing were developed and evaluated.
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TABLE OF CONTENTS
ABSTRACT IV
LIST OF TABLES VI
LIST OF FIGURES VII
Chapter 1
RESEARCH BACKGROUNDS AND OBJECTIVES 9
1.1. Forward osmosis (FO) 9
1.2. Forward osmosis (FO) dewatering process 10
1.2.1. FO dewatering 10
1.2.2. Fouling issues and attempts to overcome 11
1.3. Ultrasound for fouling control 13
1.3.1. Ultrasound 13
1.3.2. Mechanism of ultrasound fouling control 13
1.3.3. Ultrasound operation parameters during membrane
filtration 14
1.4. Activated sludge 14
1.5. Research objectives 15
Chapter 2
LITERATURE SURVEY 16
2.1. Introduction 16
2.2. Dewatering by FO process 19
2.2.1. Zero liquid discharge (ZLD) 21
2.2.2. Wastewater reduction 22
2.2.2.1. Activated sludge from wastewater treatment 23
2.2.2.2. Oil and gas wastewater 25
2.2.2.3. Landfill leachate 27
2.2.3. Resource recovery 28
2.2.3.1. Food process 29
2.2.3.2. Pharmaceutical process 31
2.2.3.3. Algae harvesting 33
2.3. Fouling issue in FO dewatering 35
2.3.1. Effect of feed composition on fouling 36
2.3.2. Membrane characteristic on fouling 41
2.3.3. Fouling control for high concentration feed
solutions 45
Chapter 3
Dewatering of activated sludge by forward osmosis (FO) with ultrasound for fouling control 50
3.1. Introduction 50
3.2. Materials and methods 55
3.2.1. Preparation of feed and draw solution 55
3.2.2. FO systems 56
3.2.3. A novel FO module for introduction of ultrasound
57
3.2.4. Batch test 58
3.2.5. Cleaning test 59
3.2.6. Analytical methods 59
3.2.7. Calculation of fouling resistance 60
3.3. Results and discussion 61
3.3.1. Dewatering of activated sludge in FO 61
3.3.2. Analysis of the impact of ultrasound on FO
fouling control 64
3.3.3. Fouling control with ultrasound cleaning 71
3.3.3.1. Radiation period 71
3.3.3.2. Combination of ultrasound cleaning with
flushing 74
Chapter 4
SUMMARY AND CONCLUSION 79
Chapter 5
REFERENCES 81
