송상훈 Sang-hoon Song , 김란희 Ran-hui Kim , 이남훈 Nam-hoon Lee , 박진규 Jin-kyu Park

DOI:10.9786/kswm.2022.39.6.477

Abstract

First-order decay models have been used to estimate annual landfill methane emissions for national greenhouse gas inventories. These models vary greatly. Inaccurate input values or oversimplified processes, such as methane oxidation or dynamic methane emission rates, cause this downside. Direct field measurements can be used to predict total methane emissions more accurately. Methane emission rates fluctuate weekly and daily and are influenced by the soil cover and meteorological conditions such as barometric pressure, temperature, rain, and wind speed. Hotspot emissions contribute significantly to landfill methane emissions. To accurately estimate annual methane emissions, direct field measurements must account for meteorological effects and quantify hotspot emissions during landfill emission monitoring programs. In South Korea, there are no field-based calculations, hampering the development of a strategic strategy to reduce methane emissions from solid waste landfills. South Korea must develop innovative methods to quantify landfill methane emissions and a mitigation strategy.

Key Words

Municipal solid waste landfill, Methane emission, Meteorologic parameters, Hotspot

박윤수 Yoon Soo Park , 전태완 Tae-wan Jeon , 신선경 Sun-kyoung Shin , 엄남일 Nam-il Um

DOI:10.9786/kswm.2022.39.6.489

Abstract

The export and import waste generated in Korea amounts to 2.63 million tons per year (about 4% of total industrial waste). During importing and exporting waste, an item code called the Harmonized System of Korea (HSK) is assigned to it through classification, inspection, and customs clearance procedures. This study prepared methods for identifying the current status of HSK, systematizing HSK, and effectively applying HSK. First, the following were investigated: the status of the HSK Code, the current status of HSK management in Korea, and HSK related to waste. As a result, Korea adopted the HSK classification table and operated with it as a notice by the Ministry of Economy and Finance. A system of 10 units is used, and there are about 339 HSK related to waste. Second, it was found that there were wastes without HSK or that some items did not match. 119 new HSK were proposed for 17 types of imported and exported waste. Third, it was found that, at times, responsible personnel made the wrong decision or intentionally entered incorrect HSK in the process of importing and exporting waste. Designated and ordinary industrial wastes under the “Waste Control Act” of Korea need to be linked with the HSK.

Key Words

Export and import waste, HS code, HSK

박진규 Jin-kyu Park , 송상훈 Sang-hoon Song , 김란희 Ran-hui Kim , 전연호 Yeon-ho Jeon , 이남훈 Nam-hoon Lee

DOI:10.9786/kswm.2022.39.6.498

Abstract

South Korea’s most recent national inventory report found that landfills are the largest anthropogenic source of methane. Despite decades of closure, landfill methane emissions threaten human health and climate change. This study investigates landfill gas (LFG) valorization to reduce these emissions. This technique converts LFG into value-added chemicals like biomethane, syngas (a mixture of carbon monoxide and hydrogen), methanol, and dimethyl ether. LFG valorization is an interesting approach to mitigate greenhouse gas emissions and shift toward a low-carbon society, but it is not economically feasible. To reduce carbon emissions and boost LFG valorization in South Korea, a carbon tax and/or subsidies may be considered. Establishing a sustainable LFG valorization technology would provide enough momentum to create a circular carbon-based economy.

Key Words

Climate change, Municipal solid waste, Landfill gas, Valorization, Carbon tax

이종효 Jong Hyo Lee , 황용우 Yong Woo Hwang , 황윤수 Youn Soo Hwang

DOI:10.9786/kswm.2022.39.6.510

Abstract

In this study, we compare the environmental loads of the coffee waste wooden deck and the general wooden deck using the life cycle assessment (LCA). We estimate the coffee waste wooden deck’s environmental advantages by LCA methodology. According to our findings, a coffee waste wooden deck reduces environmental load by 13.2% when compared to a general wooden deck. The reduction ratio for eutrophication potential was 20.4%, acidification potential was 19.4%, and global warming potential was 15.9%. Among the six environmental impact categories, abiotic depletion had the least reduction. In particular, while CO₂ emission reduction may seem insignificant numerically from the functional unit's perspective, it can be considered a significant reduction effect given the characteristics of building materials. Assuming the trail construction, which has 3.6 m of width and 360 m of length (1,320 m²), the reduction effect of the environmental load is approximately 11.6 ton CO₂-eq. Moreover, it reduces environmental load by 11.6 tons of CO₂ equivalent per year and absorbs as much GHGs as 4,936 pine trees or 3,277 oak trees. This study helps management and policymakers visualize the impact of recycling coffee waste on the environment.

Key Words

Coffee waste, Wooden deck, Life cycle assessment, Environmental impact assessment, Global warming potential

엄희숙 Hee Suk Eom , 전병준 Byung Jun Jeon , 신동훈 Donghoon Shin

DOI:10.9786/kswm.2022.39.6.521

Abstract

Biochar is a charcoal-like material that separates and stores the carbon component of organic biomass that is grown by absorbing the greenhouse gas emissions produced from burning fuel. Interestingly, when biochar is used as an additive during mortar production, the effect of the stored greenhouse gas is evident in the characteristics of the building. In this study, we experimentally evaluate the bending strength of mortar when biochar partially replaces the content of sand in mortar production. Under the condition that the ratio of cement to sand is 1: 3, in the range of 0% to 9.3% based on the mass of cement, we produce specimens in which some sand had been replaced with biochar in 4 cm × 16 cm × 1 cm. Following this, the bending strength of these specimens is measured using a three-point bending strength-measuring device at 7 days and 28 days respectively. Our findings reveal that at up to 7% of biochar replacement rate, it is possible to produce a greenhouse gas-stored mortar without loss of mortar strength; more so, we observed that the 5% biochar replacement rate demonstrates the highest bending strength showing that the advantage of strength improvement can also be utilized.

Key Words

Biochar, Carbon neutral cement, Bending strength, Biochar oven

정연우 Yeonwoo Jeong , 류영현 Younghyun Ryu , 최상규 Sangkyu Choi , 최연석 Yeonseok Choi , 한소영 Soyoung Han , 응웬반꾸잉 Quynhvan Nguyen

DOI:10.9786/kswm.2022.39.6.532

Abstract

Carbon neutrality is a balance between emitting carbon and absorbing carbon from the soil, forest, and oceans. To achieve carbon neutrality by 2050, a variety of research on energy such as solar, wind, hydrogen, biomass, and waste energy has been performed worldwide. Bio-fuel oil and bio-crude oil are considered promising energy resources to achieve carbon neutrality because they can be effectively used not only for heat energy but also for transport fuel. In this study, an experiment on the combustion characteristics of bio-fuel oil and bio-crude oil blends was conducted. The mixtures of biofuel and conventional diesel fuel were also studied. A conventional oil burner with a 35 kW capacity was modified into a downward injection type and to adopt an air-blast atomizing nozzle. Bio-fuel oil was made from waste oil and bio-crude oil was derived from coffee grounds. The temperature distributions in the combustion chamber and the gaseous emissions were compared at various blending ratios. When the bio-fuel oil was blended with bio-crude oil from the coffee ground, nearly complete combustion was observed, except for the 100% bio-crude oil, with the emission of a large amount of CO. It was also shown that as the ratio of bio-crude oil was increased, NO concentration increased due to the nitrogen content in the bio-crude oil. In the cases where biofuel was blended with diesel fuel, all cases showed close to complete combustion, where the temperature of the combustion chamber was raised with an increasing ratio of diesel.

Key Words

Bio-fuel oil, Bio-crude oil, Coffee ground, Burner, Air-blast nozzle

류재용 Jae Yong Ryu

DOI:10.9786/kswm.2022.39.6.543

Abstract

Climate change represents a worldwide warning on global warming and has elevated awareness on the global climate crisis. As a result, worldwide changes to tackle climate change have been initiated. In compliance with the Paris agreement, Korea has declared Carbon Net Zero and implemented legislative changes. Regarding the greenhouse gas emissions in Korea, the mineral industry plays a large role among other industries. A huge amount of greenhouse gases is emitted during the decarboxylation and calcination processes in the cement production process. Therefore, to address the climate crisis, the cement industry also needs to develop technologies to promote carbon neutrality. This study was conducted to explore ways to control SF₆, of which GWP is the highest, using cement kiln and thermal plasma, and to recycle the byproduct of pyrolysis into an eco-friendly cement supplementary material by immobilizing it with calcium oxide. The destruction and removal efficiency of SF₆ was 100%, while the immobilization reaction rate calculated from the concentration change of the by-product was 99.4%. As a by-product of the immobilization reaction, cement subsidiary raw materials such as fluorite (CaF₂) and anhydrite (CaSO₄) were generated, and it is thought that recycling of these raw materials is possible.

Key Words

Sulfur hexafluoride, Powder type calcium oxide, High-temperature, Immobilization, Recycle

박세인 Se-in Park , 이유민 Youmin Lee , 남궁훤 Hueon Namkung , 강준구 Jun-gu Kang , 전태완 Taewan Jeon

DOI:10.9786/kswm.2022.39.6.553

Abstract

Although the need for new and renewable energy is increasing, support for waste-to-energy facilities has been reduced as the related laws have been amended. Accordingly, there are concerns about the weakening of the competitiveness of waste-to-energy facilities. Therefore, this research conducted a study on the support methodology for waste-to-energy facilities. To provide support for waste-to-energy facilities, it is necessary to evaluate the related facilities based on common factors. In this study, for the evaluation of waste-to-energy facilities, the environmental indicator was calculated by using the environmental properties of the facility as a factor, while the benefit calculated by examining the energy production of the waste-to-energy facility was used as the economic indicator. In addition, the numerical values of each indicator were simplified through normalization, and the scores of the environmental and economic indicators were calculated by scoring the normalized values. For the calculated result, the sum of the environmental and economical scores was used as the overall score of the facility by applying the indicator reflection ratio.

Key Words

Waste-to-energy facilities, Evaluation methodology, Environmental indicator, Economic indicator

이은송 Eunsong Lee , 김진태 Jintae Kim , 이정규 Jungyu Lee , 신완호 Wanho Shin , 한소영 Soyoung Han , 홍원석 Wonseok Hong , 윤진한 Jinhan Yun

DOI:10.9786/kswm.2022.39.6.562

Abstract

This study evaluated the effect of the COVID-19 pandemic on nitrogen oxides emissions from a medical waste incinerator. During the summer vacation season and year-end periods, the amount of medical waste as well as COVID- 19 patients dramatically increased by 2 to 6 times. In addition, nitrogen oxide emissions increased by approximately 30 % due to the injection of high calorific medical waste into the medical waste incinerator. The increase in medical waste calorific value is attributed to the exclusion of diapers from the medical waste classification and the composition of synthetic resins in waste transport containers. By applying the energy conservation law, the estimated waste calorific value for the months with the highest and lowest nitrogen oxides emissions were ~5,250 kcal/kg and 4,760 kcal/kg, respectively. The correlation between waste calorific value and nitrogen oxide was confirmed. However, the calorific value of medical waste varies for each transport container, and there is a limit in constantly controlling the calorific value of the injected waste. Therefore, to minimize the environmental impact of medical waste incinerators, it is necessary to apply combustion optimization technologies such as flue gas recirculation and air staging combustion to control air pollution.

Key Words

COVID-19, Medical waste, Incinerator, Nitrogen oxide, Calorific value

정득준 Deukjun Jeong , 김관용 Gwanyong Kim , 이상철 Sangchul Lee

DOI:10.9786/kswm.2022.39.6.572

Abstract

This study is on an upcycle technology for manufacturing gasket sheets using solid waste generated in the manufacturing process of natural leather. Regarding the manufacturing of rubber gasket sheets based on dry manufacturing technology, we studied the crosslinking characteristics and mechanical characteristics of shaving scrap and trimming scrap according to the types of natural leather waste, where the effect of the type of silica used as a reinforcing filler was investigated. As a result, research on industrial recycling items that reduce carbon usage and do not generate wastewater was conducted.

Key Words

Leather waste, Rubber gasket sheet, Silica, Dry process