목차

Chapter 1. Introduction 1
1.1 Overview 1
1.2 Objectives 4
1.3 Structure of the dissertation 5
Chapter 2. Background and literature review 8
2.1 Physical and chemical properties of struvite 8
2.2 The mechanisms of struvite crystallization 11
2.2.1 Nucleation and nucleation rate 13
2.2.2 Induction time 14
2.2.3 Crystal growth 17
2.3 Factors affecting struvite crystallization 18
2.3.1 Molar ratio 18
2.3.2 pH 21
2.3.3 Aeration rate 23
2.3.4 Supersaturation ratio 24
2.3.5 Temperature 25
2.3.6 Mixing energy or turbulence 26
2.3.7 Presence of foreign ions 26
2.4 Fertilizer quality of struvite 27
2.4.1 Nutrient leaching rate 27
2.4.2 Soil type and struvite 29
Chapter 3. Effects of pH and molar ratios on phosphorus recovery through struvite crystallization 46
Abstract 46
3.1 Introduction 47
3.2 Materials and methods 49
3.2.1 Materials 49
3.2.2 Crystallizations experiments 50
3.2.3 Struvite crystal size distribution experiments 50
3.2.4 Crystal growth analysis and MINTEQ model 53
3.3 Results and discussion 53
3.3.1 Effect of magnesium, ammonium, and phosphate molar ratios on
struvite formation 53
3.3.2 Effect of pH on ammonia N and phosphate P removal 62
3.3.3 Effect of pH on struvite crystal size distribution 66
3.3.4 Composition of recovered struvite 71
3.4 Conclusion 73
Chapter 4. Application of the pre-treatment, seed materials and the concentrate water from seawater desalination to improve the struvite crystallization 79
Abstract 79
4.1 Introduction 80
4.2 Materials and methods 83
4.2.1 Pre-treatment for phosphate P release 83
4.2.2 Concentration water 84
4.2.3 Anaerobically digested effluent of livestock wastewater 85
4.2.4 Reactor operation 85
4.2.5 Analysis 87
4.3 Results and discussion 88
4.3.1 Pre-treatments affecting phosphate P release 88
4.3.2 Formation of struvite by using concentrated seawater 92
4.3.3 Effect of phosphate injection 92
4.3.4 Effect of seed materials 92
4.4 Conclusion 96
Chapter 5. Characteristics of vegetables crop cultivation and nutrient leaching as a slow-release fertilizer 101
Abstract 101
5.1 Introduction 102
5.2 Materials and methods 104
5.2.1 Anaerobically digested effluent of livestock wastewater 104
5.2.2 Struvite crystallization 104
5.2.3 Soil column test for nutrients leaching 106
5.2.4 Vegetables growth experiment 107
5.2.5 Analytical methods 108
5.3 Results and discussion 111
5.3.1 Crystallization of struvite 111
5.3.2 Nutrients leaching from soil column 114
5.3.3 Cultivation of vegetables using wastewater struvite 116
5.4 Conclusion 124
Chapter 6. An economic evaluation of phosphorus recovery as struvite from anaerobically digested effluent 127
Abstract 127
6.1 Introduction 128
6.2 Economic assessment 130
6.2.1 Economic evaluation conditions and selection of scenarios 130
6.2.2 Total capital investment cost 132
6.2.3 Operating cost 135
6.3 Results and discussion 137
6.4 Conclusion 139
Chapter 7. Conclusions and future works 142
7.1 Summary and conclusions 142
7.2 Future works 144
Abstract (in Korean) 145