• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.182-188
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• 2008

The compounds of recycled polyethylene(PE) and fly-ashes were prepared. Polymers used were sorted PE from mixed plastics of household waste and Low Density Polyethylene(LDPE) and Linear Low Density Polyethylene(LLDPE) recycled from the scrap of packaging film plants. Fly-ashes were from the power plant and from the household waste incinerator. The tensile strength of recycled LDPE and LLDPE compounds decreased and the flexural modulus increased with greater amount of the power plant fly-ash. Anthracite fly-ash gave rise to slightly higher tensile and flexural strength of the LLDPE mixtures than bituminous coal fly-ash presumably due to higher content of unburned carbon. The incinerator fly-ash introduced to household waste PE enhanced both tensile strength and flexural modulus of the compounds. When LDPE and household waste PE were used together, the synergistic effect of incinerator fly-ash to household waste PE was offset by reduced crystallization of LDPE due to the filler particle. The compounds of household waste PE and incinerator fly-ash might be applied to structural materials for such as sewage pipe, which reduces the waste treatment cost and conserve the environment and resources.

• Journal of the Korea Organic Resources Recycling Association
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• v.5 no.2
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• pp.1-6
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• 1997

Three plants for slaughtering cattle and hogs are located within 13 km away from Ithe downtown of Seoul. They are Woosung at Majang-dong, Hyubjin at Doksan-dong and Chookhyup at Garak-dong. The Objectives of this research are 1) to investigate the current status of three plants 2) to investigate wastewatrer characteristics for slaughtering platns, 3) to find out the pollution loadings to the Han river. The conclusions drawn from this research are given below: (1) The ratio of BOD/COD from the wastewater for three plants is 0.8~0.9. Most components of watewater can be biodegradable. (2) The pollution unit of BOD/cattle hog was the 726 g for Chookhyup, 777 g for Woosung and 797 g for Hyupjin plant. The average pollution unit of wastewater was 767 g BOD/cattle hog for slaughtering plant and $112.6g/m^2{\cdot}d$ for meat markets wastewater. (3) The total pollution loading was 5,050 kg/day for three wastewater plants and this amount can be affected as much as 1 % of total pollution loading of the Han River.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2001.05b
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• pp.85-91
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• 2001

This paper provides a case study of landfill gas (LFG) utilization fer direct use as process fuel, and for electrical power generation at restored landfills in the Hong Kong Special Administrative Region of China (HKSAR). The paper specifically covers the LFG utilization schemes, which are required under landfill restoration contracts at the Shuen Wan and Urban Landfills. These contracts provide for the restoration and aftercare of six landfills, and are administered by the Environmental Protection Department (EPD) of the Hong Kong Government. The LFG utilization scheme at the Shuen Wan Landfill incorporates the direct use of LFG by compressing and dehumidifying the LFG prior to conveyance through a 1.6-kilometer (1-mile) pipeline. The pipeline provides an alternate fuel source to naphtha during process heating for gas production at the Tai Po Gas Production Plant of the Hong Kong and China Gas Limited (HKCC). The LFG utilization scheme at the Jordan Valley Landfill (one of the Urban Landfills) beneficially uses the LFG as fuel for electrical power generation with reciprocating internal combustion engines. The LFG is compressed, cooled, and filtered prior to delivery to two engine/generator sets. This system provides power to operate the leachate pre-treatment plant, which processes leachate from all of the Urban Landfill sites. The case study will examine the technical and non-technical considerations, including harriers, for developing, designing and implementing the LFG utilization projects in Hong Kong. Specific regulatory considerations and external governmental agency approvals are discussed, including the requirement to register as a gas-producing utility. While the paper focuses on LFG utilization applications in Hong Kong, many of the considerations discussed are also applicable to development of LFG utilization in other regions of Asia.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.5
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• pp.716-729
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• 2015

Small-scale household digesters have been promoted across Asia as a sustainable way of handling manure. The major advantages are that they produce biogas and reduce odor. However their disadvantages include the low recycling of nutrients, because digestate is dilute and therefore difficult to transport, and the loss of biogas as a result of cracks and the intentional release of excess biogas. In this study, life cycle assessment (LCA) methodology was used to assess the environmental impacts associated with biogas digesters in Vietnam. Handling 1,000 kg of liquid manure and 100 kg of solid manure in a system with a biogas digester reduced the impact potential from 4.4 kg carbon dioxide ($CO_2$) equivalents to 3.2 kg $CO_2$ equivalents compared with traditional manure management. However, this advantage could easily be compromised if digester construction is considered in the LCA or in situations where there is an excess of biogas which is intentionally released. A sensitivity analysis showed that biogas digesters could be a means of reducing global warming if methane emissions can be kept low. In terms of eutrophication, farms with biogas digesters had 3 to 4 times greater impacts. In order to make biogas digesters sustainable, methods for recycling digestates are urgently required.

• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.2
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• pp.27-33
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• 1996

Effect of effective microorganisms on the growth of plant (salvia sp.) was investigated. Microorganisms used were photosynthetic bacteria, lactic acid bacteria and yeasts. When photosynthetic bacteria were inoculated to soil by 100 dilution, treated plants showed 160% growth by length compared to control. When photosynthetic bacteria, lactic acid bacteria and yeasts were mixed, diluted by 10 and inoculated to soil, the plants showed 212% growth compared to control. Microbial populations were increased in the treated soil.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.4
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• pp.54-63
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• 2010

When MBT(Mechanical Biological Treatment) facility is designed, the management system adequate for domestic circumstance in Korea has been insufficient and power plant's load on seasonal variation has not been resolved yet. Thus, this study introduced MBT facility and MSW(Municipal Solid Waste)'s seasonal emission characteristics were investigated in order to establish new MBT management system. and additional thermal buffer-materials's calorific values were also considered to reduce the power plant's load. The results showed that the screening efficiency of MBT facility and the physical characteristics of each waste can be identified, and the calorific value by seasonal variation for MBT facility can be kept constant all the year round by using an additional thermal buffer-materials.

• Plant Resources
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• v.3 no.2
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• pp.110-117
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• 2000

The recycling method of enokitake cultural waste and the potentiality of second flush for enokitake were determined, because this fungus is not as prolific as the more commonly cultivated white rot fungi in the conversion of sawdust to mycelial mass. The mycelial growth of F. velutipes on several substrates, variously treated with rice bran was promoted at ratios of 10-20% (w/w) on all substrates, but suppressed at above ratios, although some difference was there. The mycelial densities generally increased correlated to the supplementation contents of rice bran. It could be concluded that F. velutipes preferred mild acidic to acidic conditions for mycelial growth, considering that the mycelial growth rate was highest on waste of pH 6.01, treated with 0.1 % Ca(OH)$_2$ and on populus mixed waste of pH 6.02, non treated. The ranges of substrate bulk densities, which was pertinent for mycelial linear growth were from B.D. (g/cc) 0.17 to 0.23 on waste and populus mixed waste all. The pertinent contents of rice bran supplementation in bottle cultivation was from 20 to 30% on waste and 20% on populus mixed waste, considering the requried duration for pinheading and fruiting yields. Standard bulk density for filling and utilizing the waste and populus mixed waste for commercial f. velutipes cultivation were B.D.(g/cc) 0.19 ~ 0.23, and 0.23~ 0.25, which could be conversed to 510~ 540g/900m1 and 520~ 570g/900m1, respectively, The second flush of F. velutipes was tried and the re-inoculation by sawdust and liquid spawn showed somewhat good results, indicating the potentiality of second crop and suggesting further research for it.

• Resources Recycling
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• v.29 no.2
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• pp.37-47
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• 2020

According to Vietnam government establishes additional thermal power plant, processing the coal ash from power plant is urgent issue. This study targeted reducing unburned carbon contents in low quality fly ash to below 6% that according to international standards. As a result, the unburned carbon contents of low quality fly ash was high and irregular as 5.3~23.6%, and it was possible to reduce unburned cabon contents to under 6%, in case of unburned carbon contents below 9.8% ashes using air classification, in case of unburned carbon contents below 23.6% ashes using combined process composed of air classification and electrostatic separation.

• Resources Recycling
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• v.26 no.1
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• pp.11-15
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• 2017

The amount of the wood chip ash is expected to increase continuously as demand of wood chip-based heat and electricity increase. Thus, there is increased interest in wood chip ash utilization. In this study, as a program of utilization in wood chip ash, the physical and chemical properties of wood chip ashes generated from a combined heat and power plant were investigated. The chemical analysis showed that the main contents of wood chip ash are composed of silica, alumina and alkali. A possibility of reuse as secondary cementitious materials was investigated by the analysis of strength activity index, and compared with coal ash. The highest value for Strength activity index of wood chip fly ash was 78% at 90 days curing time. This result revealed that wood chip fly ash has the potential to be utilized as the admixture for cementitious material.

• Resources Recycling
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• v.14 no.2
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• pp.56-61
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• 2005

Economic feasibility for retrofitting the wet bottom ash handling system to the dry system in a existing 500MW${\times}$2 units pulverized coal thermal power plant in Korea was studied. Replacing to the dry system requires the initial capital costs of 13,415,127,000\, and saves the operating costs of 935,345,000\ per year. Economic analyses based on these results showed that the initial capital cost would not be recovered within the service life of the facilities at the interest rate of 10%, and the internal rate of return of 5.6% were obtained. Thus, the retrofitting to the dry system was not economically favorable in the current condition. However, the retrofitting would be profitable when the ash disposal cost and ash selling price were increased over 15,000\/MT or 17,000\/MT, respectively.