전도성 물질의 특성이 직접종간전자전달(DIET)반응 기반 혐기성소화 효율에 미치는 영향 평가 = A Study on Direct Interspecies Electron Transfer(DIET)-Mediated Anaerobic Digestion Efficiency According to Different Properties of Conductive Materials

다국어 초록 (Multilingual Abstract)

Direct interspecies electron transfer (DIET) has gained increasing attention as a viable strategy for improving the stability and performance of anaerobic digestion(AD), particularly in sludge treatment systems prone to organic overloading, VFA accumulation, or microbial imbalance. Building on this framework, the present study investigates how two widely used conductive materials activated carbon(AC) and zero valent iron(ZVI) influence the AD of waste activated sludge(WAS) when applied across a range of concentrations. Key process indicators, including methane production, biogas yield, VFAs, and pH, were monitored to evaluate system stability, while SEM–EDS, FT-IR, XPS, and 16S rRNA sequencing were used to elucidate shifts in sludge surface properties and microbial communities.
Optimal dosing of AC (1 g/L) and ZVI (2 g/L) led to methane production increases of 27.4% and 33%, respectively, relative to the control. These enhancements are attributed to improved microbial attachment, the establishment of conductive electron transfer networks, and redox mediated microbial activation mechanisms of DIET stimulation. However, excessive addition of either material introduced detrimental effects, including over-adsorption, surface passivation, ROS formation, and Fe–S precipitation, ultimately disrupting microbial diversity and reducing methane productivity.
These findings demonstrate that conductive materials can substantially reinforce DIET driven interactions in WAS digestion when applied at appropriate concentrations. The work not only clarifies the functional roles and limitations of AC and ZVI in DIET-enhanced AD but also provides practical guidance for optimizing material selection and dosing strategies. These insights support the broader development of more resilient and efficient AD systems tailored for sludge stabilization and renewable energy production.

목차 (Table of Contents)

• I. 서 론
• 1. 연구의 배경
• 2. 연구의 목적
• Ⅱ. 이론적 배경 및 문헌 조사
• 1. 혐기성소화의 원리
• 1) 전자전달 반응 메커니즘
• (1) MIET(Mediated Interspecies Electron Transfer)
• (2) DIET(Direct Interspecies Electron Transfer)
• 2. 전도체의 종류
• 1) 탄소계 물질 기반 전도체
• (1) 활성탄
• (2) 바이오차
• (3) 그래핀과 탄소 나노 튜브
• 2) 금속계 물질 기반 전도체
• (1) Fe
• (2) Nickel
• (3) Cobalt
• Ⅲ. 재료 및 방법
• 1. 기질 및 접종원
• 2. 실험 설계 및 반응기 구성
• 3. 혐기성소화 효율 모니터링
• 1) 가스 분석
• (1) AMPTS II (Automatic Methane Potential Test System)
• (2) Gas Chromatography(TCD & FID)
• (3) Kinetic Modified(Gompertz equation)
• 2) 액상 분석
• (1) pH
• (2) SCOD(Soluble Chemical Oxygen Demand)
• 3) 고형물 분석
• (1) SEM–EDS(Scanning Electron Microscope- Energy Dispersive Spectroscopy)
• (2) FT-IR(Fourier Transform Infrared Spectroscopy)
• (3) XPS(X-ray Photoelectron Spectroscopy)
• 4) 미생물 분석
• (1) 16S rRNA Sequencing
• Ⅳ. 결과 및 고찰
• 1. 전도체 종류 및 투입량에 따른 혐기성소화 효율 비교
• 1) Biogas 및 Methane 생산량 비교
• 2) 용존 유기물 거동 평가
• 3) VFA-pH 연계 성능 평가
• 2. 전도체 투입에 따른 슬러지의 물리화학적 특성 변화
• 1) SEM–EDS 결과 및 해석
• 2) FT-IR 결과 및 해석
• 3) XPS 결과 및 해석
• 3. 미생물 군집 변화 비교
• Ⅴ. 결 론
• 참고문헌
• ABSTRACT