• Journal of the Korean Wood Science and Technology
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• v.48 no.3
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• pp.271-282
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• 2020

Sewage treatment plants are social infrastructure of cities. The sewage distribution rate in Korea is reaching 94% based on the sewage statistics based in the year of 2017. In Korean sewage treatment plants, use of PAC (Poly Aluminum Chloride) accounts for 58%. It contains a large amount of impurities (heavy metal) according to the quality standards, however, there have been insufficient efforts to reinforce the standards or technically improve the quality, which resulted in secondary pollution problems from injecting excessive coagulant. Also, the increase in the use of chemicals is leading to the increases in the annual amount of sewage sludge generated in 2017 and the need to reuse sludge. As such, this study aims to verify the possibility of reusing sludge by evaluating the stability of heavy metals based on the injection of coagulant mixture during water treatment which uses the torrefield wood powder and natural materials, and evaluating the sedimentation and heating value of sewage sludge. As a result of analyzing heavy metals (Cr, Fe, Zn, Cu, Cd, As, Pb, and Ni) from the coagulant mixture and PAC (10%), Cr, Cd, Pb, Ni, and Hg were not detected. As for Zn, while its concentration notified in the quality standards for drinking water is 3 mg/L, only a small amount of 0.007 mg/L was detected in the coagulant mixture. Maximum amounts of over double amounts of Fe, Cu, and As were found with PAC (10%) compared to the coagulant mixture. Also, an analysis of sludge sedimentation found that the coagulant mixture showed a better performance of up to double the speed of the conventional coagulant, PAC (10%). The dry-basis lower heating value of sewage sludge produced by injecting the coagulant mixture was 3,378 kcal/kg, while that of sewage sludge generated due to PAC (10%) was 3,171 kcal/kg; although both coagulants met the requirements to be used as auxiliary fuel at thermal power plants, the coagulant mixture developed in this study could secure heating values 200 kal/kg higher than the counterpart. Therefore, utilization of the coagulant mixture for water treatment rather than PAC (10%) is expected to be more environmentally stable and effective, as it helps generating sludge with better stability against heavy metals, having a faster sludge sedimentation, and higher heating value.

• Korean Journal of Heritage: History & Science
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• v.44 no.1
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• pp.30-51
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• 2011

During the process of modernization, many rural villages in Korea have experienced degeneration and breakdown, losing sustainability. However, Oeam village in Asan City, South Chungcheong Province (State-designated cultural heritage, Important Folk Material No. 236) has established itself as a unique folk village, which evolves with sustainability, pursuing the revival of Neo-traditionalism. Oeam village is a tribal village of the Yis from the Yean region and has maintained environmental, economic, and social sustainability and soundness for over five centuries. Thus, the village has sustained itself well enough to be a cultural asset with 'Outstanding Universal Value', in terms of its value as world cultural heritage. The village maintains its own identity, filled with a variety of traditional and scenic cultural assets that symbolize a gentry village. Those assets include Confucian sceneries (head family houses, ancestral shrines, tombs, gravestones, commemorative monuments, and pavilions), various assets of folk religion (totem poles, protective trees at the entrance of a village, shrines for mountain spirits, village forests), tangible and intangible cultural assets related to daily lives (vigorous family activities, rigorous ancestral rituals, family rituals, collective agriculture and protection of ecosystem), which have all been well preserved and inherited. In particular, this village is an example of a well-being community with a well-preserved folksy atmosphere, which is based on environmentally sound settlements (nature + economy + environment + community) in a village established according to geomancy, East Asia's unique principle of environmental design. In addition, the village has kept the sustainability and authenticity for more than 500 years, combining restraint towards the environment and the view of the environment which respects the natural order and cultural values (capacity + healthy + sustainability). Therefore, the Oeam folk village can be a representative example of a folksy and scenic Korean community which falls into the category of IV (to exemplify an outstanding type of building, architectural or technological ensemble, or landscape which illustrates significant stages in human history) and V (to exemplify an outstanding traditional human settlement, land-use, or sea-use which is representative of cultures, or human interaction with the environment especially when it has become vulnerable under the impact of irreversible change) of Unesco's World Cultural Heritage.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.29 no.3
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• pp.153-161
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• 2023

The worldwide effects of COVID-19 have led to a surge in online shopping and contactless services. The consumption pattern has caused the issues such as the environmental pollution together with the increase of plastic waste. Reducing the reliance on the petroleum based plastic use for the package and replacing it with environmentally friendly material are the simple ways in order to solve those problems. Paper is an eco-friendly product with high recyclability as the food packaging materials but has still poor barrier properties. A barrier coating on surface of the paper can be achieved with the proper packaging materials featuring water, gas and grease barrier. Polyethylene (PE) or polypropylene (PP) coatings which are generally laminated or coated to paper are widely used in food packaging applications to protect products from moisture and provide water or grease resistance. However, recycling of packaging containing PE or PP matrix is limited and costly because those films are difficult to degrade in the environment. This study investigated the recyclability of modified acrylic emulsion coating papers compared to PE and PP polymer matrixes as well as their mechanical and gas barrier properties. The results showed that PE or modified acrylic emulsion coated papers had better mechanical properties compared to the uncoated paper as a control. PE or PP coating papers showed strong oil resistance property, achieving a kit rating of 12. Those papers also had a significantly higher percentage of screen reject during the recycling process than modified acrylic coated paper which had a screen rejection rate of 6.25%. In addition an uncoated paper had similar value of a screen rejection rate. It may suggest that modified acrylic emulsion coating paper can be more easily recycled than PE or PP coating papers. The overall results of the study found that modified acrylic emulsion coating paper would be a viable alternative to suggest a possible solution to an environmental problem as well as enhancing the weak mechanical and poor gas barrier properties of the paper against moisture.