• Journal of Environmental Science International
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• v.32 no.11
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• pp.745-756
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• 2023

Growing stringent global regulations in Korea poses a threat to corporate sustainability. Companies must respond strategically to navigate these regulations and avoid greenwashing. Objective of this research was to analyze how Korean companies are responding to the global trend of reducing plastic use and propose improved management strategies. Seven indicators were developed to assess companies' post-plastic strategies and applied to analyze the sustainability reports of Amore Pacific and LG Household & HealthCare. These indicators included, 1) disclosure of plastic raw materials used by weight or volume, 2) disclosure of recycled plastic raw materials used by weight or volume, 3) disclosure of waste recycling, reuse amounts, and disposal using waste treatment method 4) strategies to reduce environmental impact of plastics, 5) plastic packaging, reduce, recycle, reuse, and composting (in the real environment), 6) plastic management roadmap for the circular economy, and 7) education for sustainable plastic management. Based on the review of considered companies, we propose in-listed sustainable plastics management strategies: disclosing the ratio of plastic raw materials and recycled raw materials for all products, considering recycling rate throughout the product value chain, and not only for the production phase, reviewing carbon dioxide emissions based on life cycle assessment rather than reducing plastic consumption, studying the biodegradability of biodegradable plastics in natural environment such as soil, considering the consumer's perspective.

• Textile Coloration and Finishing
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• v.35 no.3
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• pp.169-178
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• 2023

The extended use of polyester nowadays has increased the amount of waste polyester (PET) released into the environment. Although these materials don't directly harm living things or the ecosystem, their inability to biodegrade remains one of the major global threats, driving up the amount of solid waste made up of PET. Environmental concerns have approved an increasing interest in recycled PET however the production of recycled PET with sufficient mechanical properties is still a challenge. Recycled Polyester (rPET) yarns are inexpensive and have the potential to acquire better mechanical characteristics through physical treatments, particularly by using technically simple method like uniaxial drawing. This study inspected the drawn behavior of virgin PET yarns and rPET yarns under various drawing parameters by first analyzing the initial material characteristics of both yarn. The impact of stretching on mechanical and morphological properties was also investigated. The results showed that virgin PET has better properties than rPET yarn; however, mechanical properties resembling virgin PET are achieved after optimizing the draw ratio.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.335-340
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• 2010

This study was conducted to select organic materials (OM) and nitrogen sources in composting of waste mushroom bed from Agaricus bisporus. We examined physio-chemical properties of the organic materials and the mixture ratio for preparing the wasted mushroom bed (M) compost. The carbon content of sawdust was higher than those of rice straw (R) as OM source and the nitrogen content was high in the order of fowl manure (F)>> pig manure (P)> cow manure (C). The compost was prepared to maintain the criteria of above 25% organic matter and then the change of their ingredients was estimated during the process of fermentation. The temperature of waste mushroom bed+pig manure+rice straw (MRP) treatment was varied fast throughout fermentation, on the other hand the temperature of waste mushroom bed+pig manure+sawdust (MSP) treatment was steadily elevated to the middle of composting. The pH of the compost was somewhat high to pH 8.5~9.0 at the early stage, but decreased to 7.5 at the end stage of composting. The content of OM after fermentation was decreased to the level of 19~21% in rice straw, but the sawdust treatment maintained 25~27% organic matter. The waste mushroom bed+fowl manure+rice straw (MRF) treatment, which contains 26.2% organic matter and 0.68% nitrogen, was the highest among them. The volume of compost was reduced to 50% by using rice straw as organic matter, but reduced to 30% by using the sawdust. The contents of heavy metal in the compost were suitable within the legal criteria. The number of microorganisms were higher in the rice straw than those in the sawdust. It was high in the order of fowl manure> pig manure> cow manure. The major groups consisted of aerobic bacteria, gram negative bacteria and Bacillus sp. and their populations after fermentation were increased to $1{\times}10^1{\sim}1{\times}10^2\;cfu\;g^{-1}$ rather than those before fermentation. Therefore we concluded that the waste mushroom bed+fowl manure+sawdust (MSF 3:9:1 v/v/v) treatment was suitable combination for high organic matter and nitrogen source, and the periods of composting were 50~60 days.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.85-95
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• 2018

In this research, a biofilter system equipped with a biofilter process and a humidifier composed of a fluidized aerobic and an anoxic reactor, was constructed to treat odorous waste air containing hydrogen sulfide, ammonia and VOC, frequently generated from pig and poultry housing facilities, compost manufacturing factories and publicly owned facilities. Its optimum operating condition was revealed and discussed. In the experiment of complex feed, the ammonia of fed-waste air was removed by ca. 75% and more than 20% at the stage of the humidifier and the biofilter, respectively. The toluene of the fed-waste air was removed by ca. 20% and more than 70% at the stage of the humidifier and the biofilter, respectively. Therefore the water-soluble ammonia and the water-insoluble toluene were treated mainly at the stage of the humidifier and the biofilter, respectively. In addition, hydrogen sulfide was almost absorbed at the stage of the humidifier so that it was not detected at the biofilter process. In the experiment of ammonia-containing feed, the ammonia of fed-waste air was removed by ca. 65% and 35% at the stage of the humidifier and the biofilter, respectively. Its removal efficiency of ammonia at the stage of the humidifier was 10% less than that in the experiment of complex feed, due to no supply of such carbon source as toluene required in the process of denitrification. In the experiments of complex feed, ammonia-containing feed with and without (instead, glucose) the addition of yeast extract, the absorption rates of ammonia-nitrogen were ca. 0.28 mg/min, 0.23 mg/min and 0.27 mg/min, respectively. The corresponding denitrification rates in the anoxic reactor were 0.42 mg/min, 0.55 mg/min and 0.27 mg/min, respectively. In addition, in the modeling of bubble column(the fluidized aerobic reactor of the humidifier) process, the value of specific surface area(a) of bubbles multiplied by enhanced mass transfer coefficient (E $K_y$) was evaluated to be 0.12/hr.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.253-259
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• 2012

Disposal of high amount of coal combustion by-products, such as fly ash and bottom ash, is of a great concern to the country, due to the huge treatment cost and land requirement. On the other hand, those coal-ash wastes are considered to have desirable characteristics that may improve physical, chemical, and biological properties of soils. Especially, compared with fly ash, bottom ash has a larger particle size, porous surface area, and usable amount of micronutrients. In the present study, we examined bottom as a soil amendment for mitigating $CO_2$ emission and enhancing carbon sequestration in soils fertilized with organic matter (hairy vetch, green barely, and oil cake fertilizer). Through laboratory incubation, $CO_2$ released from the soil was quantitatively and periodically monitored with an enforced-aeration and high-temperature respirometer. We observed that amendment of bottom ash led to a marked reduction in $CO_2$ emission rate and cumulative amount of $CO_2$ released, which was generally proportional to the amount of bottom ash applied. We also found that the temporal patterns of $CO_2$ emission and C sequestration effects were partially dependent on the relative of proportion labile carbon and C/N ratio of the organic matter. Our results strongly suggest that amendment of bottom ash has potential benefits for fixing labile carbon as more stable soil organic matter, unless the bottom ash contains toxic levels of heavy metals or other contaminants.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.172-172
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• 2011

Anaerobic digestion(AD) has successfully been used for many applications that have conclusively demonstrated its ability to recycle biogenic wastes. AD has been successfully applied in industrial waste water treatment, stabilsation of sewage sludge, landfill management and recycling of biowaste and agricultural wastes as manure, energy crops. During AD, i.e. organic materials are decomposed by anaerobic forming bacteria and fina1ly converted to excellent fertilizer and biogas which is primarily composed of methane(CH4) and carbon dioxide(CO2) with smaller amounts of hydrogen sulfide(H2S) and ammonia(NH3), trace gases such as hydrogen(H2), nitrogen(N2), carbon monoxide(CO), oxygen(O2) and contain dust particles and siloxanes. The production and utilisation of biogas has several environmental advantages such as i)a renewable energy source, ii)reduction the release of methane to the atomsphere, iii)use as a substitute for fossil fuels. In utilisation of biogas, most of biogas produced from small scale plant e.g. farm-scale AD plant are used to provide as energy source for cooking and lighting, in most of the industrialised countries for energy recovery, environmental and safety reasons are used in combined heat and power(CHP) engines or as a supplement to natural. In particular, biogas to use as vehicle fuel or for grid injection there different biogas treatment steps are necessary, it is important to have a high energy content in biogas with biogas purification and upgrading. The energy content of biogas is in direct proportion to the methane content and by removing trace gases and carbon dioxide in the purification and upgrading process the energy content of biogas in increased. The process of purification and upgrading biogas generates new possibilities for its use since it can then replace natural gas, which is used extensively in many countries, However, those technologies add to the costs of biogas production. It is important to have an optimized purification and upgrading process in terms of low energy consumption and high efficiency giving high methane content in the upgraded gas. A number of technologies for purification and upgrading of biogas have been developed to use as a vehicle fuel or grid injection during the passed twenty years, and several technologies exist today and they are continually being improved. The biomethane which is produced from the purification and the upgrading process of biogas has gained increased attention due to rising oil and natural gas prices and increasing targets for renewable fuel quotes in many countries. New plants are continually being built and the number of biomethane plants was around 100 in 2009.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.461-468
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• 2014

Biochar is a carbon rich solid produced by the pyrolysis of biomass such as energy crops, forestry residues, and wood wastes. Biochar returned to soil is to mitigate climate change and the feedstock of wood wastes reduces fossil fuel consumption as well as disposal costs. This study was practiced to evaluate a biochar system by gasification in terms of global warming regarding the soil application of the produced biochar. Life cycle assessment methodology was used to analyze the environmental impacts of the system, and the functional unit was 1 tonne of wood wastes. The result shows that the biochar system by using wood wastes as feedstock produces 4.048E-01 $kgCO_2-eq$ from the pre-treatment process as chipping and drying, 4.579E-01 $kgCO_2-eq$ from the pyrolysis process, and 9.070E-02 $kgCO_2-eq$ from the spreading to agricultural land, therefore total 9.534E-01 $kgCO_2-eq$ are generated. About 252 kg of $CO_2$ is still stored in the produced biochar in soil after carbon offsetting of the system. Therefore, the net carbon of the system is -251 kg of $CO_2-eq$.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.2
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• pp.55-62
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• 1996

The purpose of this study is the evaluation of adsorption capacity of casts for heavy metals comparing with the activated carbon. The casts was obtained from vermicomposting of the mixed organic sludges which were generated from the treatment facilities for leather wastewater and cattle wastewater. The physico-chemical characteristics of cast was investigated. Also, the batch adsorption experiments of cast and activated carbon for heavy metals were carried out, and the results were analyzed by Freundlich isotherm. The buffering capacity to the acidic wastewater was founded in the cast, and the cation exchange capacity of cast impling adsorption capacity for soluble substances was evaluated as about 55me/100g. Those were implied that the cast have a large potential as a good adsorbent for soluble pollutants in wastewater. From the results of batch experiments, the removal efficiencies of tested various heavy metals including Pb, Cu, Cd, and Cr were very high value as 89-98% for the activated car-bon, and 80~95% for the casts except for Zn. The adsorption equilibriums for the two materials were achieved within 90 minutes. The order of preferable metals in the adsorption was found to be Pb>Cu>Cd>Cr>Zn on the cast and to be Pb>Cd>Cu>Cr>Zn on the activated carbon, respectively. From the above results, it might be con-cluded that cast is effectively available as a good adsorbent to treating the heavy metal bearing wastewater.

• Economic and Environmental Geology
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• v.53 no.3
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• pp.297-306
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• 2020

The red mud generated from bauxite during the Bayer alumina production process has been regarded as an industrial waste due to the high alkaline property and high content of Na. Despite of its environmental problem, various studies for recovery of the valuable resources from red mud has been also carried out because of high content (25.7 wt.% as Fe₂O₃ in this study) of iron in red mud. In order to recover the iron resource in the red mud, microwave heating experiments were performed with adding of activated carbon and elemental sulfur to the red mud. Through the microwave heating the powdered red mud mixtures converted to porous and vitrified solid aggregates. The vitrified aggregates produced by microwave heating are composed of goethite, zero valent iron (Fe⁰), pyrrhotite and pyrite. And then, the microwave heating samples were dissolved in the aqua regia solution, and Fe precipitates were obtained as a Fe-chlorides by adding of NaCl salt in the aqua regia solution. The Fe recovery rates in the Fe-chloride precipitates showed differences depending on the experimental mixture conditions, and Fe grades of the end products are 49.0 wt.%, 58.0 wt.% and 59.5 wt.% under mixture conditions of red mud, red mud + activated carbon, and red mud + activated carbon + elemental S, respectively. The Fe content of 56.0 wt.% is generally known as the grade value of Fe in a iron ore for iron production, and the Fe grades of microwave heating samples with adding activated carbon and elemental S in this study are higher than the grade value of 56.0 wt.%.

• Clean Technology
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• v.28 no.3
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• pp.203-209
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• 2022

An environmental evaluation was conducted by employing LCA methodology for a mechanical seal manufacturing process that uses recycled silicon recovered from end-of-cycle PV modules. The recycled silicon was purified and reacted with carbon to synthesize β-SiC particles. Then the particles underwent compression molding, calcination and heat treatment to produce a product. Field data were collected and the potential environmental impacts of each stage were calculated using the LCI DB of the Ministry of Environment. The assessment was based on 6 categories, which were abiotic resource depletion, acidification, eutrophication, global warming, ozone depletion and photochemical oxidant creation. The environmental impacts by category were 45 kg CO₂ for global warming and 2.23 kg C₂H₄ for photochemical oxide creation, and the overall environmental impact by photochemical oxide creation, resource depletion and global warming had a high contribution of 98.7% based on weighted analysis. The wet process of fine grinding and mixing the raw silicon and carbon, and SiC granulation were major factors that caused the environmental impacts. These impacts need to be reduced by converting to a dry process and using a system to recover and reuse the solvent emitted to the atmosphere. It was analyzed that the environmental impacts of resource depletion and global warming decreased by 53.9% and 60.7%, respectively, by recycling silicon from end-of-cycle PV modules. Weighted analysis showed that the overall environmental impact decreased by 27%, and the LCA analysis confirmed that recycling waste modules could be a major means of resource saving and realizing carbon neutrality.