• Journal Abbreviation : J. Korea Soc. Waste Manag.
• Frequency : issued six times a year
• Doi Prefix : 10,9786/kswm
• ISSN : 2093-2322 (print)
• ISSN : 2287-5638 (online)
• Year of Launching : 1984.12.
• Publisher : Prof. Seok-Wan Kim (Daegu Hanny University)
• indexed/Tracked/Covered By :
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Effects of pH Buffering Caused by Mg2+ and Ca2+ on CO2 Absorption Amounts in a Seawater Based Carbon Capture (SBCC) System 해수기반 탄소포집(Seawater Based Carbon Capture) 시스템에서 Mg2+ 및 Ca2+에 의한 pH 완충이 CO2 흡수량에 미치는 영향
Effects of pH Buffering Caused by Mg2+ and Ca2+ on CO2 Absorption Amounts in a Seawater Based Carbon Capture (SBCC) System 해수기반 탄소포집(Seawater Based Carbon Capture) 시스템에서 Mg2+ 및 Ca2+에 의한 pH 완충이 CO2 흡수량에 미치는 영향
This study evaluated the feasibility of using seawater as a solvent for CO2 absorption in developing a seawater-based carbon capture system, a novel technology for CO2 reduction. Particularly, the effects of precipitates formed by hydroxyl ions from NaOH and Mg2+ and Ca2+ in the seawater on CO2 absorption capacity and efficiency were investigated. A semibatch CO2 absorption reactor system was set up and operated with various alkaline pH conditions using distilled water as a control and artificial seawater. Compared to freshwater, artificial seawater showed about 1,000 mg-C/L higher CO2 absorption amounts at pH 11-12.5 and a 1,365 mg-C/L higher value at pH 13. The hydroxyl ion redissolution phenomenon, which occurs as pH decreases, primarily explains these experimental results. In other words, at the initial pH levels of 11, 12, and 12.5, Mg2+ existed as Mg(OH)2; however, at the initial pH level of 13, Ca2+ also existed as Ca(OH)2. Thus, more effective CO2 absorption can be achieved at pH 13 than at pH 11-12.5 when considering the pH buffering provided by the hydroxyl ions released during redissolution. In addition, the analysis of Mg2+ and Ca2+ during the evaluation of the CO2 absorption performance of seawater confirmed that the CaCO3 precipitation reaction occurred at pH 11-13, consuming the pH buffer component CO32+, which may partially suppress the CO2 absorption efficiency. In conclusion, the advantages of using seawater as a CO2 absorption solvent were compared to freshwater regarding pH buffering capacity. Seawater may serve as a promising CO2 absorption solvent if the redissolution of magnesium and calcium in the alkaline region can be optimized.
Key Words
Seawater, CO2 absorption, pH buffering, Mg2+, Mineral carbonation
Evaluation of the Applicability of Iron Oxide-modified Lignin as a Stabilizer for Arsenic-contaminated Soil 산화철 개질 리그닌의 비소 오염 토양 안정화제로서 적용가능성 평가
서민예 Minye Seo , 조우리 Woori Cho , 이정현 Jeong-hyeon Lee , 박혜원 Hyewon Park , 이재영 Jai-young Lee
Evaluation of the Applicability of Iron Oxide-modified Lignin as a Stabilizer for Arsenic-contaminated Soil 산화철 개질 리그닌의 비소 오염 토양 안정화제로서 적용가능성 평가
서민예 Minye Seo , 조우리 Woori Cho , 이정현 Jeong-hyeon Lee , 박혜원 Hyewon Park , 이재영 Jai-young Lee
DOI:10.9786/kswm.2025.42.3.130
Abstract
This study evaluated the potential of iron oxide-modified lignin as a stabilizing agent for arsenic-contaminated soil. It also aimed to identify optimal synthesis ratios of iron oxide and lignin, determine appropriate mixing proportions, evaluate stabilization efficiency, and elucidate the stabilization mechanisms. Four stabilizers―LnFe25, LnFe50, LnFe75, and LnFe100―were synthesized by incorporating 25, 50, 75, and 100 grams of iron oxide into 20 grams of lignin, respectively. Batch stirring experiments revealed that while lignin alone increased arsenic mobility, iron-modified lignin significantly reduced arsenic leaching, confirming its stabilization efficacy. The optimal stabilization conditions were found with LnFe50 at a 5% mixing ratio, offering a favorable balance between effectiveness and economic viability. To assess stabilization performance, the toxicity characteristic leaching procedure, synthetic precipitation leaching procedure, and Wenzel tests were employed. The results demonstrated a marked reduction in arsenic leaching when using iron oxide-modified lignin compared to lignin alone. Mechanistic investigations through X-ray diffraction and scanning electron microscopy revealed that arsenic strongly adsorbs to the iron oxide component of the stabilizer, primarily through surface chemical interactions. These findings confirmed that the iron oxide-modified lignin stabilizer prevents arsenic from penetrating the iron oxide crystal structure, forming stable surface complexes instead. In conclusion, iron oxide-modified lignin presents a promising and sustainable solution for stabilizing arsenic-contaminated soil, providing an environmentally effective approach using waste materials for remediation.
Key Words
Arsenic, Contaminated soil, Stabilization, Lignin, Iron oxide
Comparative Life Cycle Assessment and Economic Evaluation of Anaerobic Digestion Processes for Biogas Production from Sewage Sludge
Comparative Life Cycle Assessment and Economic Evaluation of Anaerobic Digestion Processes for Biogas Production from Sewage Sludge
Jungsu Park , Do-yeon Kim , Sang-hyoun Kim
DOI:10.9786/kswm.2025.42.3.138
Abstract
This study investigated the economic feasibility and environmental impact of advanced anaerobic digestion (AD) technologies for sewage sludge treatment. Three processes were evaluated: (1) conventional single-stage AD without pretreatment, (2) single-stage AD with alkaline-thermal pretreatment using an anaerobic dynamic membrane bioreactor (AnDMBR), and (3) two-stage AD with alkaline-thermal pretreatment using an AnDMBR. Energy balances and net present value (NPV) analyses were conducted based on methane production data at a hydraulic retention time of 12 days. Additionally, a life cycle assessment focusing on global warming potential (GWP) was performed to assess each system’s carbon neutrality. The two-stage AD process achieved the highest net cash flow (USD 1,005,508/year) and NPV (USD 11.77 million over 20 years), with a significantly lower GWP per unit energy produced (0.31 kg CO2-eq/kWh) compared to the conventional system (0.48 kg CO2-eq/kWh). These findings suggest that integrating alkaline-thermal pretreatment with AnDMBR technology can substantially enhance the economic and environmental sustainability of sewage sludge management.
Key Words
Anaerobic digestion, Biogas, Sludge, Life cycle assessment (LCA), Economic assessment
Characteristics of Phosphate Phosphorus Removal from a Water Recycling Center Using Biochar Derived from Dried Sludge 건조슬러지 바이오차를 활용한 물재생센터 인산염 인 제거 특성
박영호 Youngho Park , 김민철 Mincheol Kim , 유대동 Deadong Yoo , 심예섭 Yaeseop Shim
Characteristics of Phosphate Phosphorus Removal from a Water Recycling Center Using Biochar Derived from Dried Sludge 건조슬러지 바이오차를 활용한 물재생센터 인산염 인 제거 특성
박영호 Youngho Park , 김민철 Mincheol Kim , 유대동 Deadong Yoo , 심예섭 Yaeseop Shim
DOI:10.9786/kswm.2025.42.3.147
Abstract
Biochar, produced from dried sewage sludge at the T Center in Seoul, was evaluated as a water treatment adsorbent. Biochar was prepared at 400-700℃ for 30 minutes. The study examined its physical and chemical properties of the biochar―including BET surface area, FT-IR spectroscopy, elemental analysis (EA), and field emission scanning electron microscopy (FE-SEM)―to characterize the pyrolysis temperature effects on specific surface area, pore structure, functional groups, and elemental composition (C, H, O, N, S). To assess phosphate adsorption capacity, isothermal adsorption experiments were conducted using 0.25 g of biochar at PO4-P concentrations of 6.25, 12.5, 25, 50, and 100 mg/L. Practical applicability was tested using artificial water simulating secondary sedimentation tank effluent and return liquor treatment facility effluent. Results showed that biochar achieved 75% phosphate removal in artificial water simulating secondary effluent characteristics, but only 35% in return liquor treatment facility effluent. Heavy metal leaching remained within regulatory limits, ensuring environmental safety. This study confirms the feasibility of upcycling sewage sludge into biochar, providing cost-effective and environmentally friendly benefits for wastewater treatment.
Key Words
Water recycling center, Dried sludge, Pyrolysis, Bio-char, Adsorption
Review of Methane Oxidation Factor Estimation Criteria and Methods for First-order Decay Model Application FOD 모델 적용을 위한 메탄 산화계수(OX) 산정 기준 및 방법 고찰
송상훈 Sang-hoon Song , 박현준 Hyun-jun Park , 박민선 Min-seon Park , 이남훈 Nam-hoon Lee , 박진규 Jin-kyu Park
Review of Methane Oxidation Factor Estimation Criteria and Methods for First-order Decay Model Application FOD 모델 적용을 위한 메탄 산화계수(OX) 산정 기준 및 방법 고찰
송상훈 Sang-hoon Song , 박현준 Hyun-jun Park , 박민선 Min-seon Park , 이남훈 Nam-hoon Lee , 박진규 Jin-kyu Park
DOI:10.9786/kswm.2025.42.3.155
Abstract
This study reviews key considerations and estimation methods for applying the oxidation factor (OX) in the Intergovernmental Panel on Climate Change first-order decay (FOD) model, supporting the development of country-specific default values and facilitating the future application of OX in biological methane mitigation strategies. When estimating greenhouse gas emissions from solid waste landfills using the FOD model, it is essential to consider landfill gas recovery systems. In landfills equipped with gas recovery systems, it is generally assumed that all uncaptured methane migrates into the landfill cover soil, and the OX represents the methane oxidation efficiency within the landfill cover soil. For landfills without recovery systems, the OX should reflect the proportion of total methane oxidized, considering both emissions to the atmosphere and transfer into the landfill cover soil. The OX indicates the overall oxidation efficiency, rather than the oxidation occurring solely within the landfill cover soil. Methane oxidation efficiencies can be estimated using three methods: CO2/CH4 ratio, mass balance, and stable isotope analysis. The CO2/CH4 ratio method is simple but has low accuracy and is only applicable to landfills with high methane flux, where CO2 from soil respiration is negligible. Furthermore, the mass balance method accounts for CO2 produced through soil respiration, but it has limitations owing to its reliance on point-based measurements. Stable isotope analysis is the most accurate method but is expensive and subject to variability in the fractionation factor, requiring site-specific evaluation.
