박상우 Sang-woo Park

DOI:10.9786/kswm.2024.41.2.103

Abstract

The demand of critical raw materials (CRMs) is expected to increase for the green and digital transitions to materialize. This also applies to the European Union (EU), which leads the carbon neutrality and transition to a circular economy. Since the implementation of the Raw Material Initiative in 2008, the EU has compiled lists of CRMs every three years. The EU outlined the CRM Action Plan in September 2020 and the CRM initiative in March 2023, after the 2019 announcement of the European Green Deal. The CRM initiative accompanied legislative measures that aimed to reinforce the CRM value chain, monitor supply and future risks, improve circularity and sustainability, and diversify CRM imports. Therefore, the EU has made proactive efforts to ensure a sustainable supply of CRMs that is in line with the core objectives of its industrial strategies for green and digital transitions. Considering its high dependence on resources and CRM imports, Korea must consistently implement appropriate policies and ensure a stable supply of sources through legislative measures. The transition to carbon neutrality and a circular economy is not a choice but a necessity, and having a consistent supply of CRMs is essential for gaining an advantage in emerging markets.

Key Words

Carbon Neutrality, Circular Economy, Raw material policies, Sustainability, CRM

박상우 Sang-woo Park

DOI:10.9786/kswm.2024.41.2.120

Abstract

Investments are required to successfully transition toward carbon neutrality and a circular economy. Private capital flows should be reoriented toward environmentally sustainable economic activities. Thus far, the European Union (EU) has been developing sustainable finance policies. Representative actions to implement the policies include the establishment of the ESG Technical Screening Criteria (TSC) and disclosure standards. Moreover, the proportions of turnover, capital expenditure, and operating expenditure are stipulated as key performance indicators that companies should disclose in relation to economic activities that are environmentally sustainable. The TSC requires that companies’ economic activities make a substantial contribution to six environmental objectives and adhere to the Do No Significant Harm (DNSH) principle. Provisions in the Taxonomy Regulation on the TSC and Corporate Sustainability Reporting Directive mandate the sustainability reporting of companies and set forth the rules to establish disclosure standards, indicating that they are designed to facilitate an interconnected and harmonized implementation. In conclusion, the EU’s sustainable finance policies demonstrate its commitment to establishing a financial framework for facilitating a seamless green transition in business practices to ultimately achieve a transition to a sustainable economy. Therefore, Korea must take proactive steps to establish future directions and principles for its industries, which would enable a successful transition of their business activities to economic sustainability.

Key Words

Carbon Neutrality, Circular Economy, ESG, Taxonomy Criteria, Disclosure Standards

박상우 Sang-woo Park

DOI:10.9786/kswm.2024.41.2.136

Abstract

The EU has been preparing policies and legislation for the green transition. Examples include policies and legislation aimed at achieving carbon neutrality and transitioning toward a circular economy. As the green transition requires significant funding, financial policies have been promoted simultaneously to direct funding and investment flows toward sustainable economic activities. Typical examples are 1) laws such as taxonomy regulations to classify economic activities that contribute to climate and environmental goals, and 2) laws to mandate sustainability disclosure and reporting to provide transparency for both companies and investors. In addition, legislation to promote the transparency and integrity of ESG evaluation company activities is being discussed. Moreover, transition financing has also been provided to support not only those companies with good sustainability practices, but also those with various starting points that have clear sustainability goals. Therefore, the EU is taking measures to promote the flow of funding and investments into sustainable economic activities to achieve climate and environmental goals. Such measures are also essential for export-driven countries such as Korea. Because ESG management is not an option but a requirement, a comprehensive financial framework and foundation for green transition should be provided.

Key Words

Carbon Neutrality, Circular Economy, Finance Policy, Sustainability, ESG

이가영 Gayeong Lee , 김나원 Nawon Kim , 배성진 Sungjin Bae , 김용진 Yong-jin Kim

DOI:10.9786/kswm.2024.41.2.155

Abstract

Currently, some of the plastic waste, which accounts for a large proportion of municipal solid waste (MSW) in Korea, is treated through incineration. However, waste plastic is not completely removed by incineration treatment, and it is sometimes found in the form of microplastics (MPs) in incineration ash. Therefore, MSW incineration facilities are classified as one of the sources of microplastics. It can be expected that the MPs found in the incineration ash that have undergone a high-temperature treatment process would exhibit different characteristics from those detected in other environmental media. Therefore, in this study, nine municipal solid waste incineration facilities of different sizes were selected, and the amount and characteristics of MPs contained in incineration bottom ash (BA) generated in each facility were investigated. In addition, changes in characteristics before and after combustion were confirmed using plastic that is mainly used in everyday life. Consequently, ND ~ 158.0 MPs/kg-BA were detected in incineration ash in small- and medium-sized incineration facilities and up to 106.6 MPs/kg-BA in incineration ash in large incineration facilities. Most of the detected MPs were black, and it was difficult to determine that it was plastic with the naked eyes. In addition, combustion experiments of plastics were conducted to confirm that the characteristics of the material before and after combustion changed significantly. Results revealed that special attention was required in the detection of microplastics in incineration ash as a modified form of spectrum different from that of raw materials.

Key Words

Municipal solid waste, Incineration, Bottom ash, Microplastics, HQI

김나원 Nawon Kim , 이가영 Gayeong Lee , 김용진 Yong-jin Kim

DOI:10.9786/kswm.2024.41.2.165

Abstract

In this study, leachate samples were collected from several municipal solid waste landfills according to landfill age (less and more than 15 years), and the concentration and characteristics of microplastics (MPs) in leachate were analyzed. In addition, the correlation between leachate water quality parameters and MPs concentration was confirmed to understand the fate and distribution of MPs in leachate. Consequently, MPs were not detected in leachate from landfills less than 15 years old, and N.D ~ 1.25 MPs/L were detected in leachate from landfills older than 15 years. In addition, the ratio of MPs less than 500 μm in leachate increased with increasing landfill age. This appeared to decrease in size owing to the aging and decomposition of MPs in the landfill. Overall, as the landfill age increased, the MPs concentration increased and size decreased, but no significant changes were observed. Besides, among leachate water quality parameters, pH, total organic carbon, and suspended solids showed a strong correlation with MPs concentration. Although leachate has been reported as a direct source of MPs to the aquatic environment, research on the occurrence, characteristics, and fate of MPs present in leachate is limited. Therefore, further research is required to understand the limited elements to control and alleviate MPs in leachate.

Key Words

Municipal solid waste, Landfills, Age, Microplastics, Leachate

유성연 Seong-yeun Yoo , 김성수 Seong-su Kim , Ahmad Nadeem , Ho Thi Thu Trang , 최강일 Kangil Choe , 이재영 Jay-young Lee

DOI:10.9786/kswm.2024.41.2.175

Abstract

The amount of livestock manure has steadily increased to 142,155 tons/day in 2021, an increase of approximately 11.0% from 2011. Most livestock manure is converted into compost and liquid fertilizer, and to reduce environmental pollution, such as water pollution and excessive nutrients, an alternative pathway is required to utilize livestock manure more efficiently as an organic resource. In this study, to utilize pig manure as a resource, the physicochemical properties of hydrochar were investigated by adding organic/inorganic acid catalysts during hydrothermal carbonization (HTC). The HCl catalyst of HTC promoted the decomposition of oxygen-containing functional groups by improving dehydration, hydrolysis, and decarboxylation. Consequently, the hydrochar prepared with a HCl catalyst of HTC at 220℃ had the highest fuel ratio (0.88), carbon content (65.5 wt.%), and heating value (HHV, 6,183 kcal/kg) among those produced using conventional methods. The fuel quality of the hydrochar was comparable to that of bituminous coal in the Van Krevelen diagram.

Key Words

Hydrothermal carbonization, HTC, Hydrochar, Livestock manure, HCl catalyst, Oxygen-containing functional groups

박동인 Dongin Park , 김윤미 Yunmi Kim , 박주영 Jooyoung Park , 이동호 Dongho Rie

DOI:10.9786/kswm.2024.41.2.187

Abstract

The COVID-19 pandemic has driven a shift in lifestyle toward non-face-to-face interactions, leading to a surge in paper waste. Recycling this waste is crucial for achieving a circular economy and carbon neutrality. Corrugated cardboard, commonly used as packaging material in logistic facilities, is primarily composed of paper and is highly inflammable. It can act as the initial ignition source and significantly contribute to fire expansion. The 2020 Icheon logistic warehouse fire highlights the imperative to enhance fire safety in logistic warehouses. Thus, investigating the fire performance of paper, commonly used in logistic warehouses, is paramount for mitigating fire damage in such facilities. This study aimed to analyze how varying amounts of Guar Gum and Expanded Vermiculite affected changes in the fire performance of recycled cardboard. We conducted the ISO 5660-1 test to assess changes in fire performance and the production of CO and CO₂.

Key Words

Recycle, Waste paper, ISO 5660-1, Fire performance, Combustion gas

이원배 Wonbae Lee , 김은주 Eunju Kim , 김경우 Gyeongwoo Kim

DOI:10.9786/kswm.2024.41.2.195

Abstract

In this study, the optimum conditions of thermo-chemical pre-treatment and bio-drying method were evaluated for efficient compost of cow manure according to the analysis of moisture content, fermentation temperature, CO₂ generation amount and organic matter removal rate. As a results, the optimum conditions of thermo-chemical pre-treatment were evaluated as follows: reaction temperature 180℃, NaOH concentration 60 meq/L, reaction time 30 min in order to lower the moisture content of cow manure to 60 ~ 65%. The moisture content of cow manure was decreased about 10% compared to the untreated cow manure. The removal rate of organic matter, moisture content and loss rate of weight were evaluated 61.4%, 35.3% and 67.8% respectively, and the composting period was reduced from 25 to less than 10 days in stage III. Therefore, the operation parameters for efficient compost of cow manure using bio-drying method as follows: solubilize of raw materials, control of the initial moisture content of cow manure, remove of dried moisture and circulate of humid air.

Key Words

Livestock manure, Cow manure, Bio-drying, Composting, Humid air control

오상현 Sang Hyun Oh , 이종효 Jong Hyo Lee , 황용우 Yong Woo Hwang , 김건용 Geon Yong Kim , 김남석 Nam Seok Kim

DOI:10.9786/kswm.2024.41.2.208

Abstract

This study analyzed the potential reduction in environmental impact achieved by repurposing waste fishing nets, which constitute half of marine debris, as concrete fiber reinforcement. Using a life cycle assessment methodology, the entire process was evaluated. Additionally, a cost-benefit analysis (B/C analysis) was conducted to assess the feasibility of the fishing net recycling project. The environmental impact analysis revealed the most significant reduction occurring in the acidification potential (AP) category, with a decrease of 1.13E-01 kg SO₂-eq., indicating a reduction rate of 93.81%. Other notable reduction percentages were found in photochemical smog (POCP) at 8.14E-03 kg C₂H₄-eq. (69.54%) and eutrophication (EP) at 9.81E-03 kg PO₄ ^3-eq. (51.08%). The reductions in global warming potential (GWP), ozone depletion potential (ODP), and abiotic depletion potential (ADP) were relatively lower at 8.03E+00 kg CO₂-eq. (5.43%), 3.86E-08 kg CFC-11-eq. (2.03%), and 8.48E-03 kg Sb-eq. (2.14%), respectively. Furthermore, with raw material acquisition costs set at 10% of the price per ton of new nylon (approximately 2.8 million KRW) and post-processing recycled product sales prices at 60% of the new product price, the B/C ratio was calculated to be 3.00. Given these parameters and assuming complete sales of waste fishing net flakes, the average annual expected profit amounts to KRW 1,086.5 million, with a projected total profit of KRW 5,432.6 million over five years. This study represents the first analysis of both the environmental and economic impacts of recycling waste fishing nets as concrete reinforcement. Its significance lies in its ability to quantify and visualize the environmental impact avoidance resulting from waste resource utilization. Furthermore, given the gradual progress in the recycling of discarded fishing nets, the findings of this study are anticipated to serve as valuable foundational research data for designing domestic marine waste management measures.

Key Words

Waste fishing nets, Concrete fiber reinforcement, Life Cycle Assessment, Economic analysis, Cost-Benefit ratio

이요셉 Joseph Lee , 김승환 Seunghwan Kim , 김준현 Junhyeon Kim , 조흠 Xin Zhao , 김재영 Jae Young Kim

DOI:10.9786/kswm.2024.41.2.218

Abstract

This study analyzed the characteristics of food waste from a food waste digestion plant (with a capacity of 80 tons per day) situated in Chungju-si, Republic of Korea. Additionally, the sedimentation technique for the removal of grit was evaluated, as improper removal of grit in food waste can result in machinery failure, abrasion, clogging, sediment accumulation in digesters, and reduced treatment efficiency. The food waste exhibited total solids and volatile solids percentages of 16.2% wt. and 14.8 wt.%, respectively. Notably, the average particle size of the grits from the food waste sample measured 99 μm. Food waste containing particles larger than 1,000 μm predominantly comprised rice and leafy vegetables, whereas grit within the same particle size range predominantly consisted of hard seeds and woody shells. Conversely, food waste and grit with particles under 1,000 μm exhibited a muddy texture. The food waste demonstrated pseudo-plastic fluid behavior with a viscosity ranging from 5 to 300 Pa·s at shear rates between 1 - 30 s-1. During the design process of a settling tank aimed at achieving an 80 wt.% removal efficiency for grit present in food waste, the calculated ratio of effective length to effective depth (L/D ratio) was found to be 6,359. This value exceeds the design criterion, which specifies that the L/D ratio should be below 10. Even with the assumption of complete removal of the surface active agent from the particle, the L/D ratio was found to be 5,785. By adjusting the viscosity of the food waste to match that of water, it became feasible to achieve an L/D ratio of 0.018. Furthermore, employing a hydrocyclone resulted in an L/D ratio of 2.12. Consequently, it was concluded that pre-treatments aimed at reducing the viscosity of food waste could render both the sedimentation technique and the use of hydrocyclone for grit removal feasible.

Key Words

Grit, Food waste, Sedimentation, Surface active agent, Length, depth