조현대 Hyun Dae Cho , 상함 Ham Sang , 정재동 Jae Dong Jaung

DOI:10.9786/kswm.2015.32.8.743

Abstract

The current study is a basic research to review the possibility of using steel wire from waste tires as recycled steel fiber for construction purposes. It analyzes preexisting waste tire-related data before processing and selecting waste steel wires to compare their composition and three quality standards if appearance as defined by concrete steel fiber regulations (KS F 2564), tensile strength, and flexibility, in order to review the feasibility of reusing waste steel wires. The results showed that the waste steel wires satisfy quality standards stated in the concrete steel fiber regulation (KS F 2564), indicating that they may be reused as recycled steel fiber for concrete.

Key Words

Waste tires, Waste steel, Concrete steel fiber, Recycled steel fiber, Recycling

홍성민 Seong-min Hong , 김한래 Han-lae Kim , 박용진 Yong-jin Park , 곽성근 Sung-keun Kwak

DOI:10.9786/kswm.2015.32.8.751

Abstract

By the strengthening of sewage treated quality law and the amount of sewage sludge every year is increasing in Korea. However, it is difficult to disposal of sewage sludge due to ocean dumping restriction. As an alternative to this, drying, incineration, anaerobic digestion etc. is applied, which is uneconomical in most be processed by the consumption of energy. In particular, anaerobic digestion technology has been installed in the sewage treatment 65 plats in Korea’s STP(sewage treatment plant). It is most of the digestion efficiency requires the application of improved technology to less than 50%. As an improvement technology for most anaerobic digester, ultrasonic, electronic beam, ozone etc. solubilization method using has been mainly used. Therefore, in this study, after the wet milling particles of sludge to subject the sludge that has not been decomposed in the digested sludge circulating fluid of anaerobic digestion, was let examine the characteristic at the time of ozonation. The size of the particles before and after the wet milling, which is the measurement at each 105.26 μm and 77.18 μm, solubilization rate is increased to 23.5%. When ozonation after wet milling using sludge is determined as possible to improve the efficiency.

Key Words

Digested sludge, Ozone, Wet milling, Solubilization, Particle size

신미수 Misoo Shin , 장동순 Dongsoon Jang , 하종욱 Jongwook Ha

DOI:10.9786/kswm.2015.32.8.756

Abstract

Since HFCs does not contain Cl component, they are not harmful to the depletion of Ozone layer but require reduction especially due to the high GWP (global warming potential). The HFC 134a, known as one of typical refrigerant of HFCs is generally shown to be effectively thermally decomposed only above the temperature of 3,000℃. However, giving condition of sufficient water vapor and the temperature more than 800℃ with large heating source like in calcination reactor or blast furnace, the thermal decomposition of HFC 134a will occur easily due the component of H and O contained in water vapor. In order to investigate this phenomenological finding appeared in large scale field test, a series of experimental investigation has been made for the thermal decomposition rate of HFC 134a as a function oxygen and HFC 134a flow rate for a small tubular reactor. In this experiment the wall temperature of tubular reactor was fixed to be 900℃. In order to verify and figure out the finding by experiment, numerical calculation has also been made for the detailed reaction of HFC 134a inside the tubular reactor. The comparison between experiment and numerical calculation are in good agreement each other especially for the rate of thermal destruction at the exit of the reactor. Further, considering the efficient thermal decomposition of HFC 134a in the H₂O vapor environment with sufficient heating source, the application of the stoichiometric mixture of hydrogen and oxygen, that is, H₂+ 1/2O₂, is made numerically in the same tubular reactor, for the thermal decomposition of HFC 134a. The result appears physically acceptable and looks promising for the future method of the HFCs decomposition.

Key Words

HFC-134a, Thermal decomposition, Numerical simulation, Tubular reactor

정승현 Seung Hyun Jeong , 정병곤 Byung Gon Jeong

DOI:10.9786/kswm.2015.32.8.764

Abstract

Experiments were conducted to propose manufacturing methods to make loess ball using food wastes. Food wastes were used to improve porosity and increase specific surface area of loess ball. Red clay, food wastes and clay were used as main raw materials in making loess ball and these were mixed with varying ratio in order to find out optimum mixing ratio. The optimum mixing ratio of food wastes is evaluated to amount to 30%. In this case, 33.61 kg/cm² of compressive strength, 65.13% of porosity, 50.04% of absorbing ratio, and 6.302 m²/g of specific surface area are obtained. When evaluating cross section and the appearance of red clay ball made up of 30% food wastes through a visual inspection and SEM photograph, it can be observed that a lot of pores are formed across the red clay ball due to the volatilization of moisture and organic matter in food wastes during the high-temperature burning. Taking into account compressive strength, porosity, absorbing ratio, specific surface area, and SEM photograph altogether, the optimum mixing ratio of loess, food wastes, and clay in the loess ball were 30%, 50%, and 20%, respectively. When evaluating the cross-section and outer appearance of the loess ball that comprise 30% of food wastes by SEM photography, it can be concluded that the optimum mixing ratio of loess, food wastes, and clay in the loess ball amounts to 30%, 50%, and 20%, respectively. Compressive strength of the manufactured loess ball amounts to 42.52 kg/cm², which is 26.5% higher than the values obtained in the condition when the loess ball made without food wastes. However, the values of porosity, absorbing ratio, and specific surface area are somewhat lower than the corresponding values obtained in the condition when the loess ball was manufactured without food wastes.

Key Words

Loess ball, Food wastes, Loess, Clay, Optimun mixing ratio

이성우 Seongwoo Lee , 민경민 Kyungmin Min , 김신동 Sindong Kim , 김대근 Daekeun Kim

DOI:10.9786/kswm.2015.32.8.772

Abstract

The purpose of the present study is to examine characteristics of hydrogen sulfide adsorption using iron-activated carbon composite adsorbents prepared by ferric nitrate and ferric chloride. Prepared adsorbents were discussed on H2S adsorption capacity. Also, adsorbents were analyzed by surface analysis methods for illustrating the physical characteristics of H2S adsorption. The breakthrough tests of H2S were conducted at 3,333 ppm of inlet concentration, demonstrating that the adsorption capacity for iron-activated carbon composite adsorbents was in order of FC_AC (Ferric chloride_Activated carbon), FN_AC (Ferric nitrate_Activated carbon), FC (Ferric chloride) and FN (Ferric nitrate). Adsorption capacity of FC was 0.06 g/g, whereas FC_AC showed the highest capacity of 0.171 g/g. All adsorbents exhibited the amorphous type in physical appearance based on XRD analysis and high Fe content based on EDS analysis. The surface areas of composites were increased by adding activated carbon, exhibiting better adsorption capacity.

Key Words

Iron oxide, Hydrogen sulfide, Adsorption, FeOOH

박석현 Seng-hyun Park , 조준연 Jun-yeon Jo , 배재근 Chae-gun Phae

DOI:10.9786/kswm.2015.32.8.780

Abstract

The purpose of this study is to analysis the materials flow of steel cans from producing to discarding, finding problems in materials flow diagram in performance recycling of steel cans, and improvement ways for relevant systems and policies. Through supply various statics in KECO, it was found that the amount of steel calculated in Korea is 80,555 thousand tons. This amounts is reused from steel scrap of 35,143 thousand tons. After that producing steel was manufactured to steel plate, and manufactured steel plate produced steel cans of 273 thousand tons. The steel cans of 103.2 thousand tons was released in Korea. The 89.5 thousand tons of wastes for recycling was 86.8% for total of 103.2 thousand tons for recycling. The amount of recycling was assumed that there is no loss in collection, sorting and packing stage. According to such studies, a materials flow diagram was drafted and the problems in recycling for each stage were reviewed. In consequence plan to improve consist of materials and structure in cans in production stage, plans to restrict inclusion of foreign particles in discardment and selection section, plan to provide different support in funding and granting quality ratings in the sorting and compression section was suggested.

Key Words

Waste steel can, Recycling, Extended Producer Responsibility (EPR), Mater Flow Analysis (MFA)

강영렬 Young-yeul Kang , 최민영 Min-young Choi , 전태완 Tae-wan Jeon , 정용우 Yong-woo Jeong , 정성경 Seong-kyeong Jeon , 신선경 Sun-kyoung Shin

DOI:10.9786/kswm.2015.32.8.790

Abstract

Using of the recycled aggregates is strongly promoted to use the national resources efficiently and enhance the recycling rate of construction wastes. However, the negative impact is expected by the alkalinity elution characteristic to the water quality and soil ecology in the region where could be contacted by water like ground water, river, area nearby coast, and etc. For this reason, we developed the pH test method to use the recycled aggregate in the drainage layer and analyse the pH concentration of the sort of time change and particle size. By the ‘Korean Standard Method for Waste’, the pH concentration was ranged from 10.78 to 11.72, by the ‘Korean Standard Method for Soil’, the pH concentration was ranged from 10.73 to 11.97, by the developed pH test in this study, the pH concentration was ranged from 10.82 to 11.71. There was no difference in the pH concentration in relation to the stirring time and the spread of particle size.

Key Words

pH Characteristics, Recycled aggregates, Waste aggregates, Drainage layer

김현경 Hyeon Kyeong Kim , 변석호 Seokho Byun , 김승도 Seungdo Kim

DOI:10.9786/kswm.2015.32.8.796

Abstract

This paper applied a new methodology to estimate the generation rate of waste refrigerator using Population Balance Model as well as assigning Weibull Distribution Function as probability distribution function (PDF) of lifespan. In order to determine the generation rate of waste refrigerator, it is necessary to estimate yearly sales quantity of new refrigerator and lifespan PDF of refrigerator. The average lifespan of refrigerator is determined to be 16.8 years as a result of averaging the lifespans of 4,682 waste refrigerators. We also developed a methodology to calibrate the PDF of lifespan of waste refrigerator. The generation rate of waste refrigerator in 2014 is estimated to be 1,822,633 decreasing sharply with time. The new methodology developed here can be applied to estimate the generation rates of other e-wastes.

Key Words

Generation rate of waste refrigerators, Refrigerator inventory, Population balance model, Weibull distribution

이기석 Ki-seok Lee , 김영민 Yeong-min Kim , 현재혁 Jae-hyuk Hyun , 이우진 Woo-jin Lee

DOI:10.9786/kswm.2015.32.8.804

Abstract

According to a report ‘2012 Present Condition of National Household Refuse Resource Recovery Facility’, about 582,178 tons/year of household refuse were processed in the incineration plant, and 465,087 tons/year of bottom ash and 117,091 tons/year of fly ash were produced respectively. As incineration ash contains many kind of heavy metals such as soluble salt, copper and lead, it may lead to the leaching potential of heavy metals according to the environmental change, so it requires special care in landfill and recycling. In this study CO₂ was injected into the bottom ash, so that environmental stability such as leaching of heavy metals was reduced and increased the possibility of CO₂ fixation ability of the bottom ash was analyzed. Bottom ash of the household refuse incineration plant of I City was used as the sample of the fixation ability particle size was divided into 3 sections to analyze its components before and after carbonation using XRF. Stability of the sample was identified by the leaching test through KSLT and TCLP, and CO₂ fixation ability by the DT-TGA analysis. Test results of the fixation ability shows that stabilization of the bottom ash produced in the household refuse incineration plant by carbonation is evaluated as there is little environmental problem caused by heavy metals when it is utilized into the recycled aggregate, and economic profits can be expected due to securing new agents of the supply and demand for the recycled aggregates, the greenhouse gas emission reduction by CO₂ fixation.

Key Words

CO₂ fixation, Stabilization of heavy metal, Incinerator bottom ash, Korea standard leaching test, Toxic characteristic leaching procedure

서승덕 Seung-deok Seo , 현재혁 Jae-hyuk Hyun , 용상운 Sang-woon Yong

DOI:10.9786/kswm.2015.32.8.813

Abstract

Soil-Cement is an outstanding paving material, as it is economic, easy to construct and environmental-friendly due to its usage of natural soil. However, compared to current methods of paving, soil-cement shows low strength and low resistance on cracking, so it is necessary to supplement those drawbacks by use of some admixtures. This paper attempts to take an in-depth study of material characteristics of soil-cement mixtures with rice husk ash which is discarded as waste to enhance the strength and durability of soil-cement. To figure that out, XRF analysis was performed. From the XRF analysis results of the chemical content in rice husk ash, SiO₂ is contained as much as 64.85%. Though SiO₂ content is major in the rice husk ash, it is less than the amount expected. It is due to incineration temperature and time away from ideal environment for maximum SiO₂ content. In addition, it figured out the strength property and durability of rice husk ash added soil-cement mixture by compressive strength test. The compressive strength test of soil-cement mixtures showed the highest strength with 10% of rice husk ash added. This suggests rice husk ash has high potential as one of pozzolanic materials.

Key Words

Rice husk ash, Soil-cement, Styrene-butadiene rubber latex, Silica fume

이수웅 Suwoong Lee , 문희성 Hee-sung Moon , 김기헌 Ki-heon Kim

DOI:10.9786/kswm.2015.32.8.819

Abstract

As landfill capacity in domestic landfills has reached the limit, social problems relevant waste treatment such as conflicts among local governments have been expanded. Although it is necessary to secure additional landfill facilities for the lack of landfill facilities in Korea, it has gone through difficulties due to NIMBY syndromes. Therefore, it is necessary to reduce the amount of waste landfilled. Responding to the problems, the Korean government established ‘Act to promote the transition to the Resource Recycling Society’ to reduce landfill of recoverable resources to 0% while pushing ahead with ‘Landfill Zero Policy’ to decrease the landfill rate to less than 3% by 2020. To realize ‘Landfill Zero Policy’, the legal landfill criteria for untreated waste is necessary. EU established Landfill Directive 2003/33/EC to suggest the detailed criteria for landfill ban by waste source. Especially, Germany with the strictest regulations bans on landfill of unclassified waste and waste which should be separately collected for recycle and reuse and has various criteria such as TOC, calorific value, heavy metal and toxic substance content by leaching test, etc. In this study, TOC as an entrance criteria of municipal solid waste into landfill compared with a landfill criteria of Germany and EU.

Key Words

Total Organic Carbon (TOC), Municipal Solid Waste (MSW), Landfill zero policy

박재성 Jae-sung Park , 김옥헌 Ok-hun Kim , 김용태 Yong-tae Kim , 여운호 Woon-ho Yeo

DOI:10.9786/kswm.2015.32.8.827

Abstract

Recently many research and investment have been made for waste biomass to bio solid fuel development in Korea. In this study, monte-carlo simulation is applied to estimate the bio solid fuel product quality made from various biomass as raw materials. Commercial biomass and waste biomass raw material samples were collected to investigate the basic properties and to predict mixed effect to solid bio-fuel product. The results show that predicted subject properties about applying a single quality items was reasonable, but for mixed biomass raw material, correlations and logical relevance of several items will be need to assume that require additional consideration for it. The stochastic techniques established through this study will be applicable to bio-solid fuel product development with a variety of waste biomass.

Key Words

Bio-SRF, Monte-Carlo simulation, Bio solid fuel, Waste to energy