Title Page
Contents
ABSTRACT 9
Chapter 1. Introduction 11
1.1. Microbial electrolysis cell 11
1.2. Performance evaluation of MEC 14
1.3. Gas analysis 15
1.4. Wastewater treatment 17
Chapter2. Application of bicarbonate buffer in MECs 19
2.1. Introduction 19
2.2. Experimental 21
2.2.1. Material and reagents 21
2.2.2. Inoculation and substrate 22
2.3. Results and discussion 24
2.3.1. Effect of phosphate buffer in MEC 24
2.3.2. Comparative performance analysis with three buffers in MECs 27
2.3.3. Long-term operation of MEC using wastewater using BB and PB concentrations 31
2.4. Conclusions 34
Chapter3. Improving hydrogen production from MECs for wastewater sludge treatment with alkaline and ultrasonication pretreatments 35
3.1. Introduction 35
3.2. Experimental 37
3.2.1. Material and reagents 37
3.2.2. MEC setup 37
3.2.3. Pretreatment methods 38
3.3. Results and discussion 39
3.3.1. Pretreatment of sewage sludge 39
3.3.2. Comparison of pretreatment methods for sewage sludge 42
3.4. Conclusions 45
References 46
Abstract (in Korean) 51
Table 1. MEC studies using various types of wastewaters. 18
Table 2. Wastewater characteristics. 23
Table 3. The parameters of MEC under three conditions (50 mM PB, HCl, untreated). 26
Table 4. The MEC parameters with three types of buffers. 30
Table 5. MEC parameters for various concentrations with PB, and BB. 33
Table 6. Parameters of before and after wastewater pretreatment. 41
Table 7. The performance of microbial electrolysis cells (MECs) utilizing sludge as the substrate with different buffer types. 43
Figure 1. Structure of Microbial electrolysis cell. 13
Figure 2. Gas collection from MEC for gas chromatography analysis. 16
Figure 3. Picture of used microbial electrolysis cell used. 21
Figure 4. SEM images of carbon brush before inoculation (A) and carbon brush after inoculation (B). 22
Figure 5. Current curves obtained from MEC with 50 mM PB, HCl, and untreated wastewater (A). Performances of the MECs under different conditions COD removal, coulombic efficiency... 26
Figure 6. Chemical structure of HEPES buffer. 27
Figure 7. Each figure shows current curve with time in MECs using wastewater treated with three different buffers. (A) with PB, (B) with BB, and (C) with HEPE. 29
Figure 8. The current curve of MEC tested with various buffer concentrations (50 mM, 40 mM, 30 mM, and 20 mM) and two kinds of buffers: (A) phosphate buffer... 32
Figure 9. Wastewater pretreatment process. 41
Figure 10. The current curve of MECs utilizing sludge as the substrate, with different buffer types. (A) is bufferless, (B) is BB, and (C) is PB. 44