기능성 여재를 이용한 수직-수평흐름 조합형 인공습지의 하수 및 호소수 정화효율에 관한 연구

다국어 초록 (Multilingual Abstract)

For decades since 1960s, constructed wetlands have been heavily used worldwide for the treatment of domestic and industrial wastewater (point source pollutant) and agricultural outflow (nonpoint source pollutant). The basic biogeochemical processes in wetlands, involved in removing contaminants from wastewater, are nearly the same as those experienced in natural system. Therefore constructed wetlands have been considered environmentally sound and sustainable technology. Recently the advantages of the wetland system led to increased interests on constructed wetlands in South Korea despite the extensive site area required for their construction.
Constructed wetlands which are managed to optimize water quality improvement generally consist either of horizontal and vertical flow system. While many researches are being conducted on the use of wetlands as secondary and tertiary treatment facilities for various wastewater, the pollutant removal efficiency of constructed wetlands for the primary treatment of domestic wastewater and lake water was rarely been investigated. Constructed wetlands can vary in performance depending on the materials, such as filter media and vegetation, type of wastewater, and structural design of system. Thus, for effective use of constructed wetlands system, the skills of different type of wetlands with various conditions should be carefully examined prior to the applications.
This study developed a functional filter media as potential material for constructed wetlands and conducted laboratory experiments to evaluate its performance compared to conventional system using general sand and gravel filter media. Additionally a pilot-scale wetland combining vertical flow and horizontal flow system was constructed and operated for 9 months to investigate the applicability of filter media for treatment of different contaminated water sources, sewage and lake water. In this study horizontal flow constructed wetland is followed by vertical flow wetland in consecutive order. The vertical flow wetland system was designed to maintain aerobic conditions using natural air draft system and each system was filled with standardized filter media, and planted with reeds and iris pseudacorus on the surface of wetlands.
The result of experiments showed that functional filter media successfully removed COD, T-N, and T-P of sewage inflow by 95.6%, 75.2% and 81.2%, respectively. This results indicate greater removal efficiencies comparing to conventional system by 7.3%, 26.4% and 17.2%, respectively. Similarly removal efficiencies for lake water were improved by 50.1%, 66.1% and 54.2%, respectively. Additionally Chl-a of lake water was treated with the removal efficiency of 89.0%. In a pilot-scale experiment, the results showed that vertical flow and horizontal flow constructed wetland has significant skills in increasing DO concentration approximately by 71.4% and improving BOD, COD, SS, T-N, and T-P of sewage inflow by 97.5%, 95.6%, 98.9%, 69.0%, and 77.3%, respectively. For lake water, the system showed considerable removal efficiencies for COD, SS, T-N, and T-P by 59.4%, 63.2%, 55.0%, and 64.7%, respectively. Additionally the role of vegetation in removing nutrients by uptake was quantitatively evaluated. The results showed that reeds contribute to the removal of T-N and T-P by 5.4% and 1.6% when planted in vertical flow constructed and iris pseudacorus contribute 3.7% and 8.4%, respectively.
Overall, this study demonstrated that constructed wetlands combining vertical flow and horizontal flow system employing functional filter media and appropriate vegetation have significant efficiency as the primary treatment for improving water quality of both sewage and lake water. The limitations and requirements for sustainable operation of the wetland system should be further investigated as a future work. The advantages and performance of constructed wetlands will vary according to the cases, depending on characteristics of inflow sources, structural design, and environmental conditions. Therefore, it may be important to conduct similar quantitative experiments using alternative wetland system to determine the most appropriate technique for given conditions and applications of interest.

목차 (Table of Contents)

• Ⅰ. 서 론 1
• Ⅱ. 이론적 배경 및 연구사 5
• 1. 인공습지 5
• 1) 인공습지의 정의 및 분류 5
• 2) 인공습지의 구성요소와 정화 원리 11
• 3) 인공습지에서의 수질정화 기작 14
• 4) 인공습지용 여재 18
• 2. 인공습지 정화기술 연구사 26
• 1) 국내의 인공습지 정화기술 동향 26
• 2) 국외의 인공습지 정화기술 동향 34
• 3. 수직－수평흐름 인공습지를 조합한 수질정화 43
• 1) 하수 방류기준 및 호소수 수질환경기준 43
• 2) 수직－수평흐름 인공습지를 이용한 하수고도처리 47
• 3) 기존 호소수 정화기술의 적용 현황 48
• Ⅲ. 실험 및 방법 52
• 1. 여재의 제조 52
• 1) 여과사 및 자갈 52
• 2) 기능성 혼합여재의 제조 53
• 3) 황탈질 미생물담체의 제조 54
• 4) 영가 철 (Fe0) 담지 황토 볼의 제조 55
• 2. Lab 규모 실험장치를 이용한 여재의 성능평가 57
• 1) Lab 규모 실험장치 57
• 2) 실험방법 58
• 3. Pilot 규모 현장시험 연구 59
• 1) 연구시설의 개요 59
• 2) 연구시설의 하수처리시설 운영 62
• 3) 연구시설의 호소수 정화시설 운영 64
• 4. 인공습지 구성요소의 특성분석 및 수질평가 방법 68
• 1) 여재 특성분석 68
• 2) 수질분석 68
• 3) 여재 부착 바이오매스 및 성분분석 69
• 4) 식물체 성분분석 70
• Ⅳ. 결과 및 고찰 71
• 1. 인공습지에 적용되는 여재의 특성분석 71
• 1) 여과사 및 자갈 71
• 2) 혼합 여재 75
• 3) 황탈질 미생물 담체 79
• 4) 영가 철 (Fe0) 담지 황토볼 84
• 2. Lab 규모 실험장치를 이용한 여재의 적용 성능평가 88
• 1) 하수처리를 위한 수직－수평흐름 조합형 시스템의 적용결과 88
• 2) 호소수 정화를 위한 수직－수평흐름 조합형 시스템의 적용결과 99
• 3. Pilot 규모 수직－수평흐름 조합형 인공습지를 이용한 하수고도처리 109
• 1) pH 변화 109
• 2) 수온 변화 111
• 3) DO 변화 113
• 4) BOD 농도 변화 115
• 5) COD 농도 변화 120
• 6) SS 농도 변화 120
• 7) T-N, NH4+-N 및 NO3--N 농도변화 123
• 8) T-P 및 PO43--P 농도 변화 133
• 9) 식물의 질소 및 인의 제거 기여도 평가 138
• 4. Pilot 규모 수직－수평흐름 조합형 인공습지를 이용한 호소수 정화 143
• 1) COD 농도 변화 143
• 2) SS 농도 변화 145
• 3) T-N 농도 변화 147
• 4) T-P 농도 변화 149
• 5) Chl-a 농도 변화 151
• 6) 총 대장균군 농도 변화 153
• 7) 분원성 대장균군 농도 변화 153
• Ⅴ. 결 론 156
• 참 고 문 헌 159