• Environmental Engineering Research
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• v.21 no.1
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• pp.69-73
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• 2016

Generation of food waste is a serious issue that needs to be addressed worldwide. Developing suitable treatment methods while generating energy (methane) is a common practice for sustainable treatment of waste. In this study, methane generation by food waste was investigated in mesophilic and thermophilic regimes at various hydraulic retention times (HRTs) and organic loading rates (OLR). In temperature regimes, influent concentrations and HRTs ranged from 30 to 110 g COD/L and 18 to 30 days, respectively, which corresponding to an OLR of 1.0 to $6.1kg\;COD/m^3-d$. Better methane production and organic removal was observed under thermophilic conditions because of the enhanced hydrolysis of complex polymers and microbial activity at higher temperature. The peak methane productivities attained in thermophilic and mesophilic regimes were 1.30 and $0.99m^3/m^3-d$, respectively. The maximum methane yields were achieved at 50 g COD/L and HRT of 24 d in both cases, and the values were 264 and $221m^3/ton$ COD, respectively. The results of this study will facilitate the development of sustainable methane production technologies using food waste as a feedstock.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.1100-1107
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• 2024

The nuclear waste attributes of near-term deployable SMRs were assessed using established nuclear waste metrics, which are the DU mass, SNF mass, volume, activity, decay heat, radiotoxicity, and decommissioning LLW volumes. Metrics normalized per unit electricity generation were compared to a reference large PWR. Three SMRs, VOYGR, Natrium, and Xe-100, were selected because they represent a range of reactor and fuel technologies and are active designs deployable by the decade's end. The SMR nuclear waste attributes show both some similarities to the PWR and some significant differences caused by reactor-specific design features. The DU mass is equivalent to or slightly higher than the PWR. Back-end waste attributes for SNF disposition vary, but the differences have a limited impact on long-term repository isolation. SMR designs can vary significantly in SNF volume (and thus heat generation density). However, these differences are amenable to design optimization for handling, storage, transportation, and disposal technologies. Nuclear waste attributes from decommissioning vary depending on design and decommissioning technology choices. Given the analysis results in this study and assuming appropriate waste management system and operational optimization, there appear to be no major challenges to managing SMR nuclear wastes compared to the reference PWR.

• Korean Journal of Community Nutrition
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• v.24 no.5
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• pp.422-432
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• 2019

Objectives: The purposes of the study were to assess wastes generated in school foodservice and to identify factors influencing the generation of plate waste. Methods: A survey was administered from November 18-30 in 2015 to dietitians and nutrition teachers that were employed in schools located in Gyeonggi province. A questionnaire file and on-line survey site link were sent to the dietitians and nutrition teachers by e-mail. A total of 622 dietitians and nutrition teachers responded and 594 responses were used for data analysis after excluding 28 responses with significant missing data. Results: Plate waste was the major part of food waste generated in school foodservice. Vegetable menus and soup/stews were discarded the most as plate waste. The dietitians and nutrition teachers perceived students' unbalanced diet and lack of appreciation of food as causes of the plate waste. Regarding waste management, they were concerned about environmental contamination by food waste and felt uncomfortable about discarding food. No plate waste day was the most frequently used plate waste reduction activity, followed by newsletters on plate waste reduction. Difficulty in getting teachers' support for dietary education during meal time was rated the greatest barrier to implementing the activities. To reduce plate waste, they perceived that students should understand the importance of environment conservation, teachers should supervise students' eating during meal time, students should be educated about proper portion, and foodservice staff should improve food quality. Conclusions: To improve students' intake and reduce plate waste in school foodservice, foodservice staff need to involve students in school foodservice and improve the palatability of meals, especially vegetable dishes. School nutrition teachers and dietitians should educate students about healthy eating and environment conservation and the school community needs to understand and support plate waste reduction and healthy eating in schools.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.1
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• pp.90-99
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• 2005

This study was conducted to survey the attitude of Chuncheon citizens on food waste generation. About 50% of the citizens were generating $5{\sim}10{\ell}$ of MSW (municipal solid wastes) a week. These answers were almost from below 35 years old. And the citizens answered that the ratio of FW (food waste) to MSW were 10-30%. They were generating FW enveloped in a standardized vinyl bag after dewatering. About 10% of the answers were generating FW with MSW without any dewatering. The reason for FW generation in large quantities was to cook and buy much more food materials than needed. They thought that malodor and harmful insect were the most severe problems from FW storage. The systematic management was the most needed in individual restaurants. They answered that an individual citizen should make an effort to reduce FW generation. However, in fact, they did not do their best to try to reduce FW generation. They agreed that an individual citizen should try to reform 'present food culture' and to think FW as resources.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.2
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• pp.367-375
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• 2004

We have developed a highly efficient boiler system using the 2,600cc Diesel engine. In this system, the co-generation concept is utilized in that the electric power is produced by the generator connected to the engine, and waste heat is recovered from both the exhaust gases and the engine itself by the shell-and-tube heat exchangers. The heat exchanger connected to the engine outlet is specially designed such that it not only recovers waste heat effectively from the exhaust gases, but significantly reduces an engine noise. It is found that the total efficiency(thermal efficiency plus electric power generation efficiency) of this system reaches maximum 96.3％ which is about 15％ higher than the typical Diesel engine boiler system currently being used worldwide.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.175-180
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• 2008

Thermoelectric materials convert temperature difference to electric power for power generation and vice versa for refrigeration. Recent advances in enhancing the thermoelectric figure-of-merit shed light on efficient power generation from the waste heat available in industries and vehicles. Nanoscale phenomena with both nanoscale constituent-embedded bulk samples and nanoscale materials proving enhanced thermoelectric performance have been widely reviewed. Bulk materials of crystal-orientation and nano-structured particle embedding seem to promise a higher thermoelectric figure-of-merit and an effective power generation application. As a preliminary study, Si-Ge nanocomposite was prepared with spark plasma sintering method and its properties were examined.

• Land and Housing Review
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• v.5 no.1
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• pp.41-51
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• 2014

The amount of new apartment construction has been trending upward in 3~4% each year since 11% increase in 2002. Currently, in public apartment construction sites under separate delivery system for construction waste processing, the significant difference between estimated quantity for contract and actual amount frequently causes severe controversy among project participants. Many factors such as poor environmental management, inadequate contractual amount are assumed to influence the above problem, and the requirement to revise existing generation rates, the key criteria applied in estimating the quantities of waste, is increasing. Most of generation rates were established in early 2000's, and have difficulty in reflecting the changes from new materials and technologies accordingly. Therefore, this study aims to clarify the types of construction waste for each trade and the forecast method as preliminary work in order to develop more accurate generation rates for construction waste in new construction. To achieve this purpose, the architectural bills of quantities in ten apartment projects executed during 2010~2013 were collected, and the possible waste types and reasonable material loss ratio for each item from temporary works to owner-supplying material area were defined and compared through the workshops and interviews with the experts and on-site environmental managers. The results of this study will contribute to establishing the categories of construction waste for construction trades and proper generation rates by the indirect estimation method in new apartment construction in the follow-up study.

• Environmental Engineering Research
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• v.25 no.4
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• pp.462-469
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• 2020

This study is proposing a System Dynamics Model for estimating Greenhouse Gas (GHG) emission from treating Municipal Solid Waste (MSW) in South Korea for years 2000 to 2030. The government of country decided to decrease the total GHG emission from waste sector in 2030 as per Business-as-usual level. In context, four scenarios are generated to predict GHG emission from treating the MSW with three processes i.e., landfill, incineration and recycling. For prior step, MSW generation rate is projected for present and future case using population and waste generation per capita data. It is found that population and total MSW are directly correlated. The total population will increase to 56.27 million and total MSW will be 21.59 million tons in 2030. The methods for estimating GHG emission from landfill, incineration and recycling are adopted from IPCC, 2006 guidelines. The study indicates that Scenario 2 is best to adopt for decreasing the total GHG emission in future where recycling waste is increased to 75% and landfill waste is decreased to 7.6%. Lastly, it is concluded that choosing proper method for treating the MSW in country can result into savings of GHG emission.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.25 no.2
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• pp.23-29
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• 2019

The volume of parcel delivery is steadily increasing with the rapid growth of the global online e-commerce market. However, a large amount of packaging materials used for these parcel delivery is finally causing environmental problems as waste. The rapid increase of these packaging waste has been making many countries to research ways to reduce the generation of distribution packaging waste. In this study, we have measured the empty space ratio for 131 packagings of parcel delivery purchased through the several domestic online stores in order to investigate the present situation in connection with the degree of excessive or overpack in korean parcel delivery packagings, so that 64 packagings were exceeded 50% in the empty space ratio. And we have suggested ways to reduce the generation of distribution packaging waste raised by e-commerce-based parcel delivery through analyzing the previous research and case studies ; one is to optimize and minimize the packaging design by safe transit test(field-to-lab test), another is to develop a reusable & returnable transport packaging and system applicable in the domestic supply chain, the other is to regulate directly with a policy.

• Resources Recycling
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• v.30 no.1
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• pp.92-101
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• 2021

The status of waste generation and recycling in 32 countries in the European Union (EU), Japan, and the United States was investigated and summarized to encourage overseas market expansion for domestic urban mining industries. Among the 32 EU countries, Germany has the highest amount of material consumption and generates the largest quantity of waste. Minerals such as mine and soil wastes constitute the largest type of waste in the EU. With respect to waste treatment techniques, landfill and recycling are applied to 39% and 38% of the waste, respectively, implying the necessity to promote recycling. Japan's total waste generation declined recently to less than 400 million tons. The largest amount of waste is generated by the manufacturing industries. The proportion of total recycled waste is estimated to be slightly over 50%, but the proportions are greater than 90% for metal scrap and 60% for waste plastics. The amount of waste produced in the United States recently exceeded 265 million tons; 52.1% of the waste is landfilled, while only 25.1% is recycled. Therefore, the recycling industry has to be developed further.