Title Page
ABSTRACT
Contents
Chapter 1. INTRODUCTION 32
1.1. Research Background 32
1.2. Literature review 40
1.2.1. Biological wastewater treatment 40
1.2.2. Oxygen transfer coefficient (KLa)[이미지참조] 46
1.2.3. Biological nitrogen removal 48
1.2.4. Biological phosphorus removal 54
1.3. Algal bloom 57
1.3.1. Algal bloom monitoring 59
1.4. Thesis scope and outline 61
1.5. REFERENCE 62
Chapter 2. Application of Jet-venturi-mixer for developing low-energy-demand and highly efficient aeration process of wastewater treatment 70
Abstract 70
2.1. Introduction 71
2.2. Materials and Methods 75
2.2.1. Reactor 75
2.2.2. Measurement of oxygen mass transfer characteristics 77
2.2.3. Measurement of Power Efficiency 84
2.2.4. CFD Modeling Visualization Methods 85
2.3. Result and discussion 86
2.3.1. Air suction according to rotation speed and impeller pressure 86
2.3.2. Comparison of a JVM-applied system performance with an air diffuser aerator system 91
2.3.3. Visualization of aeration performance to conditions of water using CFD Modeling 100
2.4. Conclusions 105
2.5. References 106
Chapter 3. Applicability of Jet-venturi-mixer in biological wastewater treatment process and change in nitrogen removal efficiency for split injection 113
Abstract 113
3.1. Introduction 114
3.2. Materials and Methods 118
3.2.1. Reactor 118
3.2.2. Analysis method and properties of influent water 123
3.2.3. Comparison of nitrification efficiency of JVM and air diffuser 125
3.2.4. Flow sate and characteristics of fluid in a reaction tank to which JVM is applied 128
3.2.5. Nitrogen removal efficiency according to operating conditions and split injection 134
3.3. Result and discussion 134
3.3.1. Contaminant analysis results 135
3.3.2. Comparison of nitrification efficiency in 1.5m³ reactor 140
3.3.3. Evaluating the efficiency of agitation and aeration equipment through CFD analysis 144
3.3.4. Nitrogen removal efficiency according to split injection 158
3.4. Conclusion 160
3.5. REFERENCE 162
Chapter 4. A Study on the improvement of nitrogen removal efficiency and reduction of power consumption using influent split injection (C/N Ratio) and JVM 168
Abstract 168
4.1. Introduction 170
4.2. Material and Methods 175
4.2.1. Continuous Flow Pilot-scale Reactor 175
4.2.2. Roles of each tank 178
4.2.3. Nitrogen removal efficiency and nitrogen variation coefficient according to C/N Ratio smart automatic split injection 181
4.2.4. Analysis methods 182
4.2.5. Applying JVM to aeration tank 183
4.2.6. Reactor operation 185
4.3. Results and discussion 190
4.3.1. Analysis of influent and effluent from pilot plant 190
4.3.2. C/N Ratio split injection, smart automatic split injection system, winter season, pollutant removal efficiency for each item during the excluding winter season 198
4.3.3. Nitrogen removal efficiency and nitrogen variation coefficient according to C/N Ratio split injection and smart split injection 230
4.3.4. Comparison of power consumption of air blower (air diffuser) and JVM 234
4.3.5. Change of influent and effluent before and after smart automatic split injection 238
4.4. Conclusion 244
4.5. References 247
Chapter 5. A Study of Cyanobacterial Bloom Monitoring using Unmanned Aerial Vehicles, Spectral Indices, and Image Processing 253
Abstract 253
5.1. Introduction 255
5.2. Material and Methods 260
5.2.1. Field site and measurements 260
5.2.2. UAVs and Multispectral camera 263
5.2.3. NDVI, GNDVI, BNDVI, and NDREI assessment 266
5.2.4. Spectroscopic image data processing 268
5.3. Results and discussion 269
5.3.1. Analysis of in-situ sample data 269
5.3.2. NDVI, GNDVI, BNDVI, and NDREI assessment 275
5.4. Conclusion 285
5.5. References 286
국문초록 294
Table 2.1. Oxygen mass transfer characteristics test conditions 80
Table 2.2. KLa, OTR, VOTR, and OTE comparison of the JVM and air diffuser aerator according to tap water and MLVSS (3,000 and 6,000 mg/L)[이미지참조] 92
Table 3.1. Characteristics of the influent 124
Table 3.2. Synthetic wastewater conditions for nitrification experiments 127
Table 3.3. Input conditions for CFD evaluation 131
Table 3.4. BOD, COD, SS, T-N, NH₄-N, NO₃-N, T-P, TOC maximum, minimum, average, and standard deviation values for the reactors 136
Table 4.1. Characteristics of the influent (temperature, pH, DO, TOC, T-N, NH₄-N, NO₂, NO₃, SS) 186
Table 4.2. Analysis results of influent water during the study period (21.01–22.03) 191
Table 4.3. Comparison of BOD5 removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period[이미지참조] 200
Table 4.4. Comparison of CODMn and CODCr removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection...[이미지참조] 206
Table 4.5. Comparison of SS removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period 213
Table 4.6. Comparison of T-N, NH₄-N removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period 219
Table 4.7. Comparison of T-P removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period 226
Table 4.8. Split injection ratio and the nitrogen variation coefficient and nitrogen removal efficiency of smart automatic split injection 232
Table 4.9. Comparison of power consumption (A) between air blower (air diffuser) and JVM 235
Table 4.10. Contaminant concentration in influent and effluent during the C/N ratio split injection study 240
Table 4.11. Contaminant concentration in influent and effluent during the smart automatic split injection study period 242
Table 5.1. Wavelength and bandwidth of multispectral camera 265
Table 5.2. Equations of the spectral index used in the study 267
Table 5.3. Minimum, maximum, and average values of temperature, pH, DO, EC, and phycocyanin of each site 273
Table 5.4. Value index (NDVI, GNDVI, BNDVI, NDREI) and phycocyanin concentration correlation 284
Figure 1.1. Nitrification 50
Figure 1.2. General reaction equation for nitrification 50
Figure 1.3. Denitrification 53
Figure 1.4. Mechanism of biological P removal 56
Figure 2.1. Reactor a) JVM installed inside activated sludge reactor b) venturi type impeller 76
Figure 2.2. Air suction rate change according to impeller rotation speed and pressure head 87
Figure 2.3. Schematic diagram of Bernoulli's principle and oxygen supply flow applied in this study 89
Figure 2.4. KLa measured from the different waste waters treated by the JVM and air diffuser aerator[이미지참조] 95
Figure 2.5. Changes in OTE and E of the JVM and air diffuser aerator according to tap water and MLVSS (3,000 and 6,000 mg/L) 99
Figure 2.6. Agitation and Fluid Flow CFD Modeling (Blue line indicates agitation, fluid flow; Green line indicates impeller turning radius) a) Tap... 102
Figure 2.7. Oxygen distribution CFD Modeling a) Tap water b) MLVSS 3,000 c) MLVSS 6,000 104
Figure 3.1. Continuous Flow Reactor Used in Lab Scale 120
Figure 3.2. Membrane applied to lab scale reactor 122
Figure 3.3. Jet-venturi-mixer applied to 1.5m³ Lab scale reactor 129
Figure 3.4. Concentration change of T-N, NH₄-N for reactors 139
Figure 3.5. Comparison of nitrification of JVM and air diffuser 142
Figure 3.6. Stirring efficiency and oxygen distribution at 100, 200, 300 rpm (MLVSS 0) 147
Figure 3.7. Stirring efficiency and oxygen distribution at 100, 200, 300 rpm (MLVSS 3000) 150
Figure 3.8. Stirring efficiency and oxygen distribution at 100, 200, 300 rpm (MLVSS 5000) 153
Figure 3.9. Stirring efficiency and oxygen distribution at 100, 200, 300 rpm (MLVSS 7000) 156
Figure 3.10. Change in T-N of influent and effluent according to split injection ratio 159
Figure 4.1. Schematic layout of JVM-MBR process used in this study 176
Figure 4.2. The shape of the JVM installed in the pilot plant; a) Appearance of the device actually applied b) The shape of the impeller 184
Figure 4.3. Sensors of S::Can device applied to pilot plant 188
Figure 4.4. Changes in TOC and NH₄-N concentration of influent water for 24 hours 196
Figure 4.5. Comparison of BOD5 removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period[이미지참조] 203
Figure 4.6. Comparison of CODMn removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period[이미지참조] 209
Figure 4.7. Comparison of CODCr removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period[이미지참조] 211
Figure 4.8. Comparison of SS removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period 216
Figure 4.9. Comparison of T-N removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period 222
Figure 4.10. Comparison of NH₄-N removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period 224
Figure 4.11. Comparison of T-P removal efficiency in winter season, excluding winter season between C/N ratio split injection study period and smart automatic split injection study period 229
Figure 4.12. Changes in power consumption of JVM 236
Figure 5.1. Location of the study area and sampling area 262
Figure 5.2. Measured phycocyanin concentration at each site 271
Figure 5.3. Image processing in June (a) NDREI, (b), NDVI, (c) GNDVI (d) BNDVI 278
Figure 5.4. Image processing in August (a) NDREI, (b), NDVI, (c) GNDVI (d) BNDVI 279
Figure 5.5. Image processing in September (a) NDREI, (b), NDVI, (c) GNDVI (d) BNDVI 280