• Journal of Environmental Impact Assessment
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• v.18 no.6
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• pp.453-460
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• 2009

In order to provide fundamental data for developing high-grade(high-quality and low-pollution) Refuse Derived Fuel(RDF), we analyzed caloric value and HCl content by Municipal Solid Waste(MSW) type. The caloric value was analyzed using calorimeter and HCl content was analyzed using mercury(II) thiocyanate method. In case of paper type the caloric value was 3,060~3,608kcal/kg and the HCl content was 239~6,135ppm. In case of vinyl-plastics the caloric value was 5,946~9,888kcal/kg and the HCl content was 429~455,771ppm. According to the result of quality assessment by MSW type, the calroric value of vinyl-plastics type was showed higher than that of paper type and in case of HCl content the paper type was showed lower than vinyl-plastics type. So, We mixed paper and plastic wastes. The caloric value of mixed MSW(paper and plastics) was 5,046~9,125kcal/kg and the HCl content was 239~6,135ppm. Also, The caloric value of packaging waste(film-plastics) was 5,982~8,045kcal/kg. Therefore It is possible to develop high-grade Refuse Derived Fuel through suitable mixing of paper and plastic in municipal solid waste.

• International Journal of Advanced Culture Technology
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• v.9 no.3
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• pp.305-314
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• 2021

Currently, due to COVID-19, household waste has a lot of impact on the environment due to packaging of food delivery. In this paper, we design and implement Faster-RCNN, SSD, and YOLOv4 models for municipal waste detection and classification. The data set explores two types of plastics, which account for a large proportion of household waste, and the types of aluminum cans. To classify the plastic type and the aluminum can type, 1,083 aluminum can types and 1,003 plastic types were studied. In addition, in order to increase the accuracy, we compare and evaluate the loss value and the accuracy value for the detection of municipal waste classification using Faster-RCNN, SDD, and YoloV4 three models. As a final result of this paper, the average precision value of the SSD model is 99.99%, the average precision value of plastics is 97.65%, and the mAP value is 99.78%, which is the best result.

• Resources Recycling
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• v.29 no.4
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• pp.31-44
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• 2020

Recently, plastic recycling has emerged as a social issue, and its importance is increasing. Therefore, this article reviewed the current status and the future directions of domestic plastic recycling. Plastic recycling is major economic and social problems not only in South Korea but also worldwide and is being treated as an important factor for protecting the environment and for sustainability in the next generation. In particular, China, which has been dealing with a large amount of plastic waste generated around the world, has banned importing plastic waste, therefore, other countries have faced the problem of recycling plastics in their countries. In South Korea, the landfill and incineration of the waste are becoming more difficult by the Framework Act on Resources Circulation, therefore, the recycling and reuse of plastics are a very important.

• Journal of Integrative Natural Science
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• v.13 no.4
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• pp.158-169
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• 2020

Modern people live in the age of plastics. It has been widely used due to its easy molding processing, mass production, and excellent durability. However, over-produced plastics for convenience cause plastic disasters and adversely affect the ecosystem. Since the COVID-19 outbreak, the use of single-use plastic waste due to the use of delivery services has increased. The COVID-19 pandemic has caused a plastic pandemic. Currently, domestic recycling policies depend only on recycling collection companies and market prices of recyclable resources. This paper confirms whether the outbreak of COVID-19 has affected the price of plastic waste. It also shows that the price of plastic waste is more unstable than metals with a high recycling rate. This urges businesses to share the cost of recycling on plastic waste, no longer being dependent on market prices for recyclable resources.

• Resources Recycling
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• v.25 no.1
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• pp.31-39
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• 2016

Small household appliances such as electric rice cooker, a vacuum cleaner, an electric fan, etc. are diverse and complex due to the materials and components and waste streams from the manufacturing processes. In the present study, physical characterization of small e-wastes was analyzed on major items including electric rice cooker after manual dismantling. Small household appliances is an important potential source of waste plastic, however, recycling plastics from small e-waste is still unusual. The present communication gives results of separation processes on black plastics and the limitations of these sorting processes in used small household appliances.

• Journal of Environmental Science International
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• v.27 no.2
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• pp.91-97
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• 2018

This study carried out first a component survey on the domestic waste shipped into a waste disposal facility in B city, and then heavy metal analysis of each component according to the SRF standards. Based on this, this study explored the problems with domestic waste and measures to improve them. The results are as follows. The result of the survey of physical components show that paper accounted for the largest proportion with 20.5 %~59.9 %, metals (including batteries) among incombustibles accounted for 0.0~8.3 %, other inorganic substances, glass and ceramics accounted for 0.0~43.7 % and 0.0 %~19.6 % respectively. However, the proportion of coated viny and plastics, which have high lead and cadmium content, was rather high with 2.9 %~30.9 %. This suggests the possibility that actual concentration of lead and cadmium within SRF is likely to be higher. Among the 15 components contained in the waste brought into the waste disposal facility, 10 components (food waste, textiles, vinyl, plastics, wood, rubber and leather, paper, metals, electronic substrates, and nail polish) were analyzed according to assay samples (approximately 0.1 g and 0.3 g). The result of analysis shows that the amount of Cd and Pb detected in coated vinyl for 0.109 g of assay sample was 98.6 mg/kg and 20.6 mg/kg respectively; 117.0 mg/kg and 29.0 mg/kg respectively for 0.313 g of assay sample. This is high contents exceeding the Cd standard. As for wooden component, the amount of Pb was 480.0 mg/kg for 0.3 g of assay sample. This suggests that there always exists the possibility of exceeding the exposure level of heavy metals (Cd and Pb) in SRF as long as coated wood and vinyl plastics with high contents of Pb and Cd are shipped into the waste disposal facility; and the local government and the residents need to work hard to improve the situation including development of the machine to sort electronic substrates and batteries for separate collection of the waste of coated vinyl and plastics within domestic waste.

• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.338-347
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• 2021

Polyhydroxyalkanoates (PHA) are a family of microbial polyesters that are used as biodegradable plastics in replacement of conventional plastics for various applications. However, the high production cost is the barrier for PHA market expansion. This study aimed to utilize food waste as low-cost feedstock to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by Haloferax mediterranei. The effects of acetate (Ac), propionate (Pr), butyrate (Bu), and the short-chain carboxylates derived from food waste were examined on the microbial growth and PHBV production. Results showed that a mixture of carboxylates provided a 55% higher PHBV yield than glucose. The food-waste-derived nutrients achieved the yields of 0.41 to 0.54 g PHBV/g Ac from initial loadings of 450 mg/l to 1,800 mg/l Ac of total carboxylates. And the consumption of individual carboxylate varied between different compositions of the carbon source. The present study demonstrates the potential of using food waste as feedstock to produce PHBV by Haloferax mediterranei, which can provide economic benefits to the current PHA industry. Meanwhile, it will also help promote organic waste reduction in landfills and waste management in general.

• Analytical Science and Technology
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• v.23 no.4
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• pp.383-388
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• 2010

Catalytic dissociation reaction was studied in order to transform waste plastics to oil by using noble metal supported catalysts. XRD, SEM, and GC/MSD analysis were performed to find the crystalline structure and shape, and product distribution. Generally, dissociation reaction occurs at low temperature compared to pyrolysis. Dissociation reaction has advantage of gasoline yield with respect to pyrolysis which products mainly $C_1\simC_4$. The result of dissociation reaction, gasoline was obtained much as a product. $C_5\simC_{11}$ compounds were produced as a gasoline product on Pt-zeolite among noble metal catalysts at $340^{\circ}C$. The conversion of dissociation reaction of waste plastics on the prepared catalyst was above 70% over $340^{\circ}C$.

• Resources Recycling
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• v.14 no.2
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• pp.3-9
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• 2005

A study on the air and gravity separation has been performed for the removal of chlorine containing materials from ASR of end-of-life vehicles. The gravity separation was also conducted on waste plastics collected from ASR. In this work, ASR were previously shredded to pass through 8 mm sieve prior to separation tests and the gravity separation of waste plastics was conducted for three different particle sizes. The two-stage air classification was conducted with the range of air flow rate of 9~20 M$^3$/hr at first stage and 25~34 M$^3$/hr at second stage, respectively. The fraction of overflow product was remarkably increased in the 2nd stage air classification because of high air flow rate while that of underflow product obtained from 1st stage air classification was found to be 62~66%. From the results of gravity separation on waste plastics, it was also found that the amount of the float product was much greater than sink product. It is believed that the gravity separation may be used very efficiently for the removal of calorine bearing materials from waste plastics.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.742-745
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• 2001

Plastics are one of difficult materials for recycling due to their characteristics in use. Recycling ratio of waste plastics was around 40% in last year in Japan, which includes energy recovery. Feed stock recycling and mechanical recycling are not easy because of additives in commercial plastics. Then, pyrolysis treatments have been done to recovery energy. Although plastics are easy to fire, complete combustion of them is not easy if anti-firing agents are added especially. Therefore, researches on pyrolysis or combustion behaviors of plastics containing additives are important from a view point recycling of plastics. Direct observation of popular plastics like polystyrene (PS), polycarbonate (PC), polyphenyle ether (PPE) and polyvinyl chloride (PVC) to investigate their pyrolysis behaviors in the present study. In case of PS, melting and gas evolution started at 9$0^{\circ}C$ and 39$0^{\circ}C$ respectively. And combustion finished at 445$^{\circ}C$. On the other hand, more than $600^{\circ}C$ and sufficient oxygen are required for complete combustion of PC and PPE.