박상우 Sang-woo Park

DOI:10.9786/kswm.2023.40.6.545

Abstract

The goal of achieving carbon neutrality by 2050 and the shift toward a circular economy have become global agendas. These are vital prerequisites for economic growth, extending beyond the scope of merely addressing environmental challenges. The European Union (EU) has played a prominent role in executing these agendas. This study assessed how the EU’s environmental policies have evolved during the European integration process. The findings revealed that environmental policies have been integrated into diverse sectors of the economy and society throughout the European integration process. In addition, EU treaties have enshrined the principle of sustainable development. Environmental policies grounded in this principle have resulted in comprehensive and cohesive measures paving the way for a sustainable future for the EU economy. These efforts culminated in the formulation of the Green Deal policy in 2019, which represents the EU’s new economic growth strategy. Furthermore, subsequent measures have been introduced to legislate for attaining the 2050 carbon neutrality goal and to enhance the functioning of the EU single market. The EU treaties also mandate member states to contribute to global sustainable development, thereby actively participating in international agendas, including those related to sustainable development, carbon neutrality, and the circular economy. In conclusion, given the high probability of the EU’s environmental policies evolving into a future growth strategy, it is imperative to implement domestic measures that seamlessly integrate environmental sustainability into the economic and social sectors.

Key Words

Carbon neutrality, Circular economy, Environmental policy, Sustainable development

박상우 Sang-woo Park

DOI:10.9786/kswm.2023.40.6.560

Abstract

The global agenda is transitioning toward achieving carbon neutrality and embracing a circular economy by the year 2050. The prevailing linear economy, characterized by the consumption and discarding of resources in substantial quantities, renders current economic growth unsustainable. The EU is progressing by implementing policies and legislation aimed at embedding sustainability and circularity throughout the product lifecycle to address this inherent limitation. This study investigates trends within the EU regarding the role of waste in facilitating the transition to carbon neutrality and a circular economy and explores the trajectory of South Korean legislation in this context. The findings suggest that since the establishment of its basic waste law in 1975, the EU has consistently amended it to align with the objectives of sustainable development policies. The primary emphasis has been on incorporating sustainability throughout the product lifecycle. This feasibility is realized through a strategic approach that extends beyond waste policy to include industrial policy. A noteworthy example involves implementing an entry strategy during the production and consumption phases of the product lifecycle to facilitate substantial circularity. South Korea plans to implement policies for transitioning to a circular economy starting in 2024, in accordance with the Act to Promote the Transition to a Circular Economy Society. We anticipate the implementation of specific measures that, similar to the EU, focus on prevention and encompass the production and consumption sectors, ensuring that substantial sustainability and circularity are realized across the entire product lifecycle.

Key Words

Carbon neutrality, Circular economy, Waste legislation, Prevention, Life cycle

이가희 Gahee Lee , 정창훈 Changhoon Jeong , 천범수 Beomsu Cheon , 김학민 Hakmin Kim , 정대운 Daewoon Jeong

DOI:10.9786/kswm.2023.40.6.577

Abstract

The presence of heavy metals in paper incineration ash contributes to various environmental issues. To recycle paper incineration ash, the heavy metals in the ash were removed using ethylenediaminetetraacetic acid (EDTA) and oxalic acid. In this study, mixed solutions containing EDTA and oxalic acid concentrations of 0.05 M, 0.10 M, 0.20 M, and 0.40 M, respectively, were employed. Among the mixed solutions, the combination of 0.05 M EDTA and 0.40 M oxalic acid (0.05E+0.40O) exhibited the highest removal efficiency for heavy metals. This solution achieved the removal of 61% of Pb, 43.2% of Cu, 99.1% of As, 50% of Cd, and 40% of Hg, and it met the recycling standards for waste, as confirmed by the results. Furthermore, the calcium oxide (CaO) content increased after washing, indicating the potential for effective recycling as a substitute for cement. Therefore, it was confirmed that the removal technology developed in this study is an effective method for obtaining recyclable paper incineration ash.

Key Words

Paper incineration ash, Heavy metal removal, EDTA, Oxalic acid, Soil washing

정예진 Yeojin Jeong , 최용범 Yongbeom Choi , 우영국 Youngkook Woo , 조은하 Eunha Jo , 박준석 Joonseok Park

DOI:10.9786/kswm.2023.40.6.587

Abstract

This study aimed to comprehend the generation and treatment status of agricultural waste in Gangwon-do through statistical analysis. The average annual generation of agricultural waste, represented as synthetic resins in Gangwon-do over the past 5 years (2017-2021) was 26,057 tons/year with a coefficient value (CV) of 16.7%, which accounted for 8.3% of the nationwide amount. In Gangwon-do, low-density polyethylene (LDPE) exhibited the highest proportion among greenhouse LDPE, mulching LDPE, high-density polyethylene (HDPE), polyvinyl chloride (PVC), ethylene-vinyl acetate (EVA), and polyolefins (PO). In addition, it accounted for the largest share of mulching LDPE nationwide. The generation of agricultural waste in the form of pesticide containers in Gangwon-do over the past 5 years (2017-2021) amounted to 5,265,279 pieces/year with a CV of 8.1%, representing 7.3% of the nationwide total. The generation proportion ratio of plastic bottles (3,567,751 pieces/year, CV 8.7%) and plastic bags (1,697,528 pieces/year, CV 12.8%) in pesticide containers was approximately 2:1. The amount of agricultural waste generated by the 18 local governments of Gangwon-do exhibited a radial pattern, with a notable concentration in Hongcheon, Pyeongchang, and Hoengseong. As a result, it could be regarded as a focal point in the future when installing a treatment and recycling facility directly managed by the Korea Environment Corporation. The results of the correlation analysis conducted using SPSS revealed that factors such as agricultural land area or field cultivation area exhibited a higher correlation with the amount of agricultural waste generation than factors such as the number of agricultural populations or households engaged in field cultivation.

Key Words

Agricultural waste, Gangwon-do, Coefficient value, Treatment and recycling facility, SPSS

박채린 Chaerin Park , 정혜지 Haeji Jeung , 김은정 Eun Jung Kim

DOI:10.9786/kswm.2023.40.6.599

Abstract

Despite having high levels of organic matter and nutrients for plant growth, sewage sludge digestate is not often directly applied to soil because of harmful pathogens, pollutants, and odors. The production of biochar from sewage sludge digestate can mitigate the adverse effects associated with the direct application of digestate to soil. Furthermore, the application of biochar to soil can improve soil properties, and the functional groups on the surface of biochar can effectively adsorb contaminants. In this study, the characteristics of sewage sludge digestate biochar and hydrochar were assessed to optimize the production of chars for application in soil amendments and environmental remediation. Using dried sewage sludge digestate, biochar was produced under the nitrogen environment at temperatures of 300℃, 400℃, and 500℃, while hydrochar was produced in a hydrothermal autoclave reactor at temperatures of 160℃, 180℃, and 200℃. The physicochemical properties of biochar and hydrochar, including their elemental compositions, Fourier transfer infrared (FTIR) surface functional groups, Brauer-emmet-Teller (BET) surface areas, and lead (Pb) adsorption capacities were assessed. Hydrochar produced from sewage sludge digestate exhibited a higher yield and better Pb adsorption capacity than biochar, indicating the effectiveness of hydrochar production from sewage sludge digestate by the hydrothermal carbonization process for environmental applications.

Key Words

Sewage sludge digestate, Hydrothermal carbonization, Biochar, Hydrochar

이종명 Jongmyong Lee , 임민혜 Minhye Lim , 안광옥 Kwangok Ahn , 김창범 Changbum Kim

DOI:10.9786/kswm.2023.40.6.608

Abstract

Research on reducing greenhouse gas emissions from cement production, including carbon capture and storage (CCS), is actively ongoing. Many studies have focused on using captured carbon dioxide to enhance the carbonation reaction in cement production. The carbonation reaction of calcium silicate-based cement (CSC) is expected to be primarily applied to blocks because of challenges such as rebar corrosion. This study employed computational fluid dynamics (CFD) analysis to examine the internal flow and carbonation reactions on the mold surface within a carbonation reactor designed for block production using CSC cement. The analysis results revealed that the rotational flow inside the reactor was well formed, effectively dispersing gas outward due to the rotation. This ensured that, despite the injection of high concentrations of carbon dioxide, a consistent carbon dioxide concentration and flow distribution were maintained adjacent to the mold. These findings affirm that the design of the carbonation reactor was well executed. Furthermore, it was anticipated that the carbonation reaction between carbon dioxide and carbonate would start across the entire mold surface after 150 seconds inside the carbonation reactor. This study established an analysis model for the internal flow and reactions within the carbonation reactor, specifically for carbonating carbon dioxide. This provides a foundational basis for appropriately designing the reactor, even when its size and shape undergo modifications. The findings from this research are expected to contribute to future studies focused on improving the performance of carbonation cement and blocks.

Key Words

CO_{2 block curing, CCS cement curing, Cement CO2 mineralization, Carbon capture and use, Computational fluid dynamics}

양이정 Leejung Yang , 장한울 Hanul Jang , 이민형 Minhyeong Lee , 장현민 Hyun Min Jang

DOI:10.9786/kswm.2023.40.6.616

Abstract

Anaerobic digestion is a common method for treating organic waste. However, there is a pressing need to devise suitable solutions for managing the substantial amount of sludge generated during this process. The current study aimed to characterize and utilize anaerobically digested sludge-derived biochar (BC) for the removal of tetracycline (TC) from water. The BC demonstrated a Brunauer-Emmett-Teller (BET) surface area of 6.177 m²/g, a pore volume of 0.0257 cm³/g, and a pore size of 166.435 A. In the adsorption experiments, the maximum adsorption capacity was observed at pH 5. Furthermore, the adsorption kinetic and isotherm studies indicated a chemisorptive interaction between TC and BC through monolayer adsorption. The maximum adsorption capacity of BC for TC (54.35 mg/g) was greater than that of other adsorbents (2.71 mg/g ~ 41.35 mg/g), but less than that of activated BCs (274.81 mg/g ~ 288.3 mg/g). In summary, anaerobically digested sludge-derived BC holds significant promise for effective TC removal in water. Further research is required to optimize its adsorption capacity.

Key Words

Anaerobically digested sludge, Pyrolysis, Adsorption kinetics, Adsorption isotherm, Antibiotics

임혜숙 Hye Sook Lim , 박하늘 Ha-neul Park

DOI:10.9786/kswm.2023.40.6.623

Abstract

Recycling plastic waste is viewed as a policy alternative to attaining carbon neutrality and mitigating environmental issues such as greenhouse gas emissions and the proliferation of microplastics. A crucial initial phase in this process involves the separate collection of plastic waste for recycling. To comprehend the present situation of the plastic waste separate discharge rate in Korea, we analyzed the plastic waste separate discharge rate within municipal solid waste and examined the stochastic convergence characteristics of time series data. The findings reveal that as of 2021, the nationwide ratio of plastic waste separate discharge rate stands at 38.5%, the Gwangju Metropolitan City boasts the highest rate at 55.8%, while Gyeongsangbuk-do records the lowest rate at 12.6%. Based on the trend analysis of the plastic waste separate discharge rate, the average annual growth rate is determined to be 2.7% nationwide. The plastic waste separate discharge rate exhibited a consistent upward trend, escalating from 19.6% in 1996 to 41.6% in 2009. However, since 2010, the rate has experienced fluctuations, characterized by periods of increase and decrease, and a gradual widening of regional disparities has been observed. To understand the characteristics of the plastic waste separate discharge rate over time, a stochastic convergence analysis was undertaken, employing the unit root test on the time series data. The outcomes indicate that the time series of plastic waste separate discharge rates by region is mostly nonstationary. This implies that policies aimed at promoting the separate collection of plastic waste can be effectively implemented in the long term. Given the distinct time trends in plastic waste separate discharge rates among regions and the obvious widening gap between them, further research is necessary to investigate the factors contributing to these regional disparities.

Key Words

Plastic waste, Microplastic, Separate discharge rate, Convergence, Circular economy

한소영 Soyoung Han , 최연석 Yeon-seok Choi , 최상규 Sang-kyu Choi , 정연우 Yeon-woo Jeong

DOI:10.9786/kswm.2023.40.6.638

Abstract

Due to the increasing importance of new and renewable energy sources as alternatives to fossil fuels, worldwide attention is focused on the use of carbon-neutral biomass for energy conversion, and research is advancing toward an efficient method that uses waste biomass as an energy source. The present research provides valuable data, i.e., activation energy (E_a) values from waste biomass thermal conversion experiments. Thermochemical kinetic coefficients of several types of waste biomass were calculated using thermogravimetric analysis and isoconversional kinetic analysis models, the Friedman differential isoconversional method, and the Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose linear integral isoconversional methods. The following average E_a values were determined: 146.8-150.1 kJ/mol for sugarcane, 135.6- 145.6 kJ/mol for cornstalk, 116.5-128.2 kJ/mol for rice straw, 103.9-114.2 kJ/mol for narra, 126.5-139.1 kJ/mol for Napier grass, 158.6-171.3 kJ/mol for tobacco, 142.7-172.2 kJ/mol for waste coffee grounds, and 186.6-200.8 kJ/mol for palm kernel shells. We are confident that the biomass Ea values derived from this study will be helpful in designing optimized biomass pyrolysis processes.

Key Words

Thermogravimetric analysis, Thermochemical kinetics, Isoconversional method, Activation Energy