돈사폐수의 BMP 향상을 위한 고도산화처리 연구 = A Study on Advanced Oxidation for improving the BMP of Piggery Wastewater

다국어 초록 (Multilingual Abstract)

As a main source of pollution affecting the water quality of rivers or lakes, livestock wastewater accounts for only about 1% out of all the wastewater, but its pollutions load based on BOD is as much as 14% out of all the pollution load, compared to industrial wastewater or domestic sewage. Besides, since livestock wastewater has high concentrations of nitrogen and phosphorus as well as a high organic concentration, it brings about quite serious problems in terms of pollution load.
Especially, the domestic amount of piggery wastewater is gradually increasing every year, but due to the prohibition of its ocean disposal, it is more urgent to devise an alternative method of disposing piggery wastewater. As a kind of high-concentration organic wastewater, piggery wastewater is mainly treated through an anaerobic process, and widely used to reduce sludges and produce methane. Besides, as the advanced oxidation process of piggery wastewater improves the treatment speed by increasing hydrolysis, which is the rate-controlling step of anaerobic process.

Thus, this study treated piggery wastewater, flowing into the livestock wastewater disposal plant, through various advanced oxidation process methods, and evaluated the livestock wastewater disposal plant, through various advanced oxidation process methods, and evaluated the characteristics of methane generation through a BMP(Biochemical Methane Potential) test and a batch experiment.
To compare the solubilization of piggery wastewater, this study investigated the solubilization characteristics of piggery wastewater created through such individual treatments as Fenton oxidation treatment, alkali treatment, heat treatment and microwave treatment, ultrasonic treatment and ozone treatment, and such alkali-combined treatments as alkali-heat combined treatment, alkali-microwave combined treatment, alkali-ultrasonic combined treatment and alkali-ozone combined treatment. Piggery wastewater is high in the contents of particulate organic matters, such as cellulose, hemicellulose and lignin, since its main components are from undigested feed ingredients, and due to highly-concentrated NH4+ and toxic substances from antibiotics, the biological treatment of piggery wastewater is hindered, and its HRT is long for anaerobic digestion. To solve such problems, such an advanced oxidation process is not only to increase the amount of methane gas by improving the solubilization efficiency and biodegradability of piggery wastewater, but makes it possible to use piggery wastewater as an external carbon source when connected to other follow-up processes.

When piggery wastewater was treated through individual treatments, its solubilization rate was highest in the ultrasonic treatment with 52.90 % and 0.58 gSCODprod./gVSfed. and when treated through alkali-combined treatments, it was highest in the alkali-ultrasound combined treatment with 58.40 % and 0.64 gSCODprod./gVSfed. and in general, the solubilization rate was higher in alkali-combined treatments than individual treatments.

In the BMP test, the accumulated amount of methane gas was most in the alkali-ultrasonic combined treatment (20KHz 60min), followed by the alkali-microwave combined treatment (900W 9min), and methane was generated 112.97 % and 92.43 % more than the control group respectively. Even in the BMP test, more methane was generated in alkali-combined treatments than individual treatments, and as a result of the BMP test, the treatments with higher solubilization rates showed a higher efficiency of methane generation.

As a result of the BMP test, since the energy purely generated from piggery wastewater treated through the alkali-ultrasonic combined treatment was 11 % more than that of an anaerobic process with non-treated piggery wastewater applied, this method is expected to increase the economic efficiency. Especially, when combining the alkali treatment, whose cost for chemicals is low, with a treatment requiring a high expense for electricity like the ultrasonic treatment, it is possible to reduce the cost of electricity used for expensive ultrasonic waves and improve the proficiency of treatment, and it has a high possibility of commercialization. Besides, when organic waste resources are converted into energy through this method for the production of bio-gas, it is expected to contribute to supplementing a considerable portion of the energy consumption.

Based on the results above, this study found out that the solubilization rate and biodegradability of piggery wastewater can be improved through the alkali-ultrasonic combined treatment, further leading to increasing the productive efficiency of bio-gas, reducing the hydraulic retention time in a follow-up anaerobic process and expenses used to heat up anaerobic digesters and even the amount of sludge generated. As a result, it is anticipated that we can have economic benefits by securing an alternative energy and reducing expenses spent on disposing sludge.

목차 (Table of Contents)

• List of Table ⅳ
• List of Figure ⅴ
• List of abbreviations ⅸ
• Ⅰ. 서 론 1
• Ⅱ. 문헌연구 3
• 1. 축산폐수의 특성과 현황 4
• 2. 펜톤산화 처리 7
• 2.1 고급산화공정 7
• 2.2 고급산화공정의 분류 9
• 2.3 펜톤산화의 반응 메카니즘 11
• 2.4 펜톤산화의 주요 영향인자 16
• 2.5 펜톤산화 연구사례 20
• 3. 알칼리 처리 22
• 3.1 알칼리 처리 개요 22
• 3.2 알칼리 처리 연구사례 23
• 4. 열 처리 27
• 4.1 열 처리의 개요 27
• 4.2 열 처리 연구사례 31
• 5. Microwave 처리 33
• 5.1 Microwave 의 개요 33
• 5.2 마이크로파 가열의 원리 및 특성 38
• 5.3 연구사례 44
• 6. 초음파 처리 46
• 6.1 초음파 (Ultrasonic)의 원리 46
• 6.2 연구사례 53
• 7. 오존산화 처리 55
• 7.1 오존의 개요 및 응용원리 55
• 7.2 오존에 의한 폐수 내 생분해도 증가 60
• 7.3 오존/High pH AOP 공정 63
• 7.4 오존의 이용 64
• 7.5 연구사례 64
• Ⅲ. 실험 방법 및 분석 66
• 1. 실험개요 66
• 2. 실험재료 66
• 3. 고도산화처리 실험장치 방법 68
• 3.1 Fenton산화 처리 68
• 3.2 알칼리 처리 70
• 3.3 열 처리 70
• 3.4 Microwave 처리 72
• 3.5 초음파 처리 74
• 3.6 오존 처리 76
• 3.7 BMP(Biochemical Methane Potential)실험 77
• 4. 분석방법 및 항목 79
• Ⅳ. 연구결과 및 고찰 81
• 1. 단독 고도산화처리 81
• 1.1 펜톤산화의 적정 pH 81
• 1.2 TS 및 VS의 감량 83
• 1.3 SCOD농도 및 SCOD/TCOD비의 변화 90
• 1.4 SCOD 가용화율 99
• 1.5 NH4+-N과 PO43—P 농도의 변화 111
• 2. 병합 고도산화처리 120
• 2.1 TS 및 VS의 감량 121
• 2.2 SCOD농도 및 SCOD/TCOD비의 변화 125
• 2.3 SCOD 가용화율 130
• 2.4 NH4+-N과 PO43—P 농도의 변화 138
• 3. Volume 감량화 특성 143
• 4. 전자현미경 관찰 145
• 5. BMP(Biochmical Methane Potential) 실험 147
• 5.1 펜톤산화 처리 149
• 5.2 알칼리 처리 151
• 5.3 열 처리 153
• 5.4 Microwave 처리 156
• 5.5 초음파 처리 158
• 5.6 오존 처리 160
• 5.7 처리 방법별 메탄가스량 및 생분해성 비교 162
• 6. 경제성 평가 165
• Ⅴ. 결 론 168
• APPENDIX 170
• 참 고 문 헌 186
• Abstract 202