전상호 Sang Ho Jun , 정병학 Byoung Hak Jung , 박길옥 Kil Oak Park

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Abstract

For the test evaluation to induce vegetation to plant unproductive mine waste area, we have observed the growth process of Miscanthus sinensis grows wild in mine-waste area with molding sewage sludge in the same area. In comparison with each plant height growth (cm/month), fresh weight growth (g(fw)/month), and dry weight growth (g(dw)/month) percentage from a molding sewage sludge experimental plot and an untreated experimental plot, the average plant height growth of Miscanthus sinensis from 10% and 20% molding sewage sludge plot was 7.4 cm/month, while untreated Miscanthus sinensis was recorded 1.8 cm/month. In addition, the average biomass growth percentage (g(fw)/month) from the sewage sludge treated Miscanthus sinensis was some 19.7 g(fw)/month, which is 3.3 times higher than 6.2 g(fw)/month for the latter. The average dry weight growth percentage (g(dw)/month) of sewage sludge treated Miscanthus sinensis was also 3.3 times higher than untreated one, each of which are 3.72 g(dw)/month, 4.04 g(dw)/month for the former and 1.21 g(dw)/month for the latter. Moreover, the range and number of Miscanthus sinensis community from treated plot were greater than the other as well. We have acknowledged that the possibility of recycling sewage sludge is quite effective from the results by an experiment of molding sewage sludge in the mine waste area. As we have observed the positive possibility of sewage sludge reuse on the mine waste area in order to prevent mine waste erosion by plant restoration with the use of sewage sludge on difficult condition for plants, So it is suggested to utilize the produced sludge by small Sewage Treatment Plant which has less heavy metal and toxic substance.

Key Words

Miscanthus sinensis, Mine waste area, Tailings, Sewage sludge, Heavy metal, Fresh weight, Dry weight

김태형 Tae Hyoeng Kim , 김선웅 Seon Ung Kim , 한수현 Su Hyun Han , 이윤희 Yun Hee Lee , 황선진 Sun Jin Hwang

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Abstract

The effects of pH and C/N ratio on bio-ethanol production using Saccharomyces cerevisiae were evaluated under anaerobic/aerobic condition. The growth of microorganisms was relatively lower under anaerobic condition (1.5 OD) than under aerobic condition (2 OD), whereas the ethanol production yield was higher as 0.45 g-ethanol/g-glucose under anaerobic condition than as 0.3 g-ethanol/g-glucose under aerobic condition. Weak acid (pH 4-5) was more productive to ethanol yield compared to that at neutral condition. Various C/N ratios from 2.5 to 30 were evaluated, and the ethanol yield was observed as 0.45 g-ethanol/g-glucose at 10 to 30 of C/N ratios. The yield at low C/N ratio (below 5) was less than 0.1 g-ethanol/g-glucose and corresponding glucose consumption rate was also less than 30%.

Key Words

Saccharomyces cerevisiae, Bio-ethanol, pH, Aerobic/Anaerobic, C/N ratio

이병희 Byong Hi Lee , 이재춘 Jae Choon Lee

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Abstract

The stringent effluent water quality requirements force to use the MBR to treat wastewater. Since there is no design parameters available, especially for sludge production, the factors used for conventional activated sludge system are applied to calculate the amount of sludge produced from the MBR system. In this study, the computer simulation was used to define the yield. Four typical Korean domestic wastewater characteristics estimated from both combined and separated sewer systems were used as influent. And A2O-MBR and UCT-MBR configurations with 4 operation modes for each configuration were simulated. It was found that yield was inversely proportional to SRT. However, effluent T-N concentration and T-P removal efficiency are proportional to yield. Also, yield was inversely proportional to effluent T-P concentration. Yield showed strong relation with SRT. The yield in MBR system had a range from 0.34 to 0.43 kgMLVSS/kgBOD with Korean domestic wastewater.

Key Words

MBR, MLSS, SRT, Yield, Nutrient, F/M Ratio

송상훈 Sang Hoon Song , 김홍규 Hong Kyu Kim , 박진규 Jin Kyu Park , 이남훈 Nam Hoon Lee

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Abstract

In this study, the mathematical models for GHG emission, IPCC`s Tier 2 model, EPA`s LandGEM model, and Scholl Canyon model, were calibrated through a simulated lysimeter test and verified in a full-scale landfill. As a result of the simulated lysimeter test, it was actually measured that 593 L of landfill gas for 1,160 days was generated. The greenhouse gas emission estimated was 913 L by the Tier 2 model, 752 L by the LandGEM model, and 2,982 L by the SC model. After the calibration of the L0 value, both SC model and LandGEM model showed a significant difference in greenhouse gas emission. Consequently, these two models are mainly affected by the potential methane generation in estimation of greenhouse gas emissions. Greenhouse gas emissions which measured in landfill was 1,808 m³/yr, and Tier 2 model, SC model, and LandGEM model after calibration were estimated to 1,806 m³/yr, 201,856 m³/yr, and 3,519 m³/yr respectively. The calibrated parameter for the Tier 2 model seems to have got the appropriate value on it.

Key Words

Solid waste Landfill, GHG gas, Emission model, Calibration, Verification

김혜진 Hye Jin Kim , 정새롬 Sae Rom Jeong , 박진규 Jin Kyu Park , 김홍규 Hong Kyu Kim , 이남훈 Nam Hoon Lee

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Abstract

AT4 and GB21 are test methods for the assessment of waste biological stability. This paper investigated the correlation of aerobic (AT4) and anaerobic (GB21) methods and the biological stability to suggest biological stabilization criteria of landfilled waste. These methods for the evaluation of biological stability were carrided out using samples of waste excavated from MSW landfills. The respiration index (AT4) for the waste from the landfills varied from 8.7 to 27.32 mgO₂/gDM. For the same samples, the biogas production (GB21) varied from 13.54 to 63.95 NL/kg DM. It was found that the AT4 shows a significant correlation with the anaerobic test (GB21) with correlation coefficients(R²) of 0.79. Also, the respiration index (AT4) and biogas production (GB21) for leaf mold and sand were estimated to find biological stabilization criteria. The results show that the average respiration index (AT4) for each sample was 2.21 mgO₂/gDM (leaf mold) and 0.37 mgO₂/gDM (sand), respectively. The average biogas production was 7.61 NL/kgDM (leaf mold), 1.81 NL/kgDM (sand), respectively. The biological stability for these samples were lower than 5 mgO₂/gDM and 20 NL/kgDM (Acceptance criteria for landfill waste in Germany). Based on the AT4 and GB21 methods of this study, we suggested limit values of 4 mgO₂/gDM (AT4) and 10 NL/kgDM (GB21) for stabilization criteria of landfilled waste.

Key Words

MSW Landfill, Biological stabilization criteria, Aerobic method, AT4, Anaerobic method, GB21, Correlation coefficient

김득모 Deuck Mo Kim , 이화영 Hwa Young Lee , 박찬규 Chan Kyu Park , 문경주 Kyoung Ju Mun , 소양섭 Yang Seob Soh

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Abstract

Investigation of Cement free binder was carried out using changed alkali activator and binder. Flow, compressive strength, SEM, XRD were used to observed specification of Cement free binder. Flow of Cement free binder has two specification that flow is increased by force of repulsion between cationic and flow is decreased by surface activating. Compressive strength was proportioned by mass of alkali activator and it was increased when Ca(OH)₂ addicted in alkali activator but it was decreased when CaSO4 addicted in alkali activator.

Key Words

Geo polymer, Alkali activate slag, Activate agent, Flow, Micro structure

장영일 Young Il Jang , 박완신 Wan Shin Park , 이병재 Byung Jae Lee , 박승범 Seung Bum Park , 김윤용 Yun Young Kim , 이준 Jun Lee

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Abstract

The strength of porous concrete is decreased when coal bottom ash, a major by-product of coal thermal power plants, is used as an aggregate. In this study, the mechanical properties and application of porous concrete depending on the coal bottom ash content are evaluated. In addition, performance improvement factors such as the use of metakaolin and PVA(Polyvinyl Alcohol) fiber are evaluated as they relate to the recycling growth of coal bottom ash. The results showed that mixing 5% metakaolin and 0.05 vol.% PVA fiber led to the most significant improvements in terms of the compressive and flexural strength, the flexural toughness, and the freeze-thaw resistance. Despite the mixing ratio of 50% coal bottom ash, when the reinforcing factors were mixed in as well, the mechanical properties were equal to or higher than porous concrete only mixing crushed aggregate. Moreover, the planting and noise reduction capacity were improved slightly at a mixing ratio of 50% coal bottom ash, 5% metakaolin and 0.05 vol.% PVA fiber. With adequate reinforcing factors, coal bottom ash is expected to be utilized in large quantities as an aggregate material in porous concrete.

Key Words

Coal bottom ash, Metakaolin, PVA fiber, Mechanical properties, Application

윤진한 Jin Han Yun , 길상인 Sang In Keel , 김우현 Woo Hyun Kim , 민태진 Tai Jin Min , 장두훈 Du Hun Jang

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Abstract

Asbestos is a mineral fiber that has been used commonly in a variety of building construction materials for insulation and as a fire-retardant. Asbestos has been used for a wide range of manufactured goods, because of its fiber strength and heat resistant properties. Nevertheless harmful of asbestos is quite serious. Exposure to airborne friable asbestos may result in a potential health risk because persons breathing the air may breathe in asbestos fibers. To melt asbestos is required very high melting temperature more than 1,520℃ and specially asbestos cement slate need more energy for melting than that of pure asbestos because of cement contents. Therefore, to lower melting temperatures, or to control the basicity is inevitable to use the additives. In this paper, the waste glass was used to control basicity as additives. And we fulfilled about properties of asbestos cements slate, melting characteristics on the additives ratio and temperature, analysis of slag(SEM and XRD) etc. It is passible to lower melting temperature as a result suitable mixing the asbestos cement slate and waste glass. The result of basicity analysis, the optimal temperature is 1,400℃ and the ratio of additives is 67% condition. The results of this study will be suggested as a preliminary data for commercial plant.

Key Words

Asbestos waste, Asbestos cement slate, Asbestos melting, Basicity

권성현 Sung Hyun Kwon , 이은미 Eun Mi Lee , 조희균 Hee Gyun Jo , 박병기 Byung Gi Park , 조대철 Dae Chul Cho

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Abstract

In order to enhance the surface properties of the architectural material we manufactured a submicro-silver solution, and carried out several functional tests for its dispersity, antibiotic action, and abrasion. Fully dispersed submicro-silver solutions were optimally obtained through a reductive reaction including NaBH4 (5 mM) and Tween20 (1wt%). SDS and overdose of PVP as stabilizers resulted in poor quality of Ag suspension. The silver suspension whose concentration was 600 ppm or more could extinguished more than 99.5% of the test bacteria whereas sterilizing efficiency of the powder silver was only 50%. The coated layer formed by spreading the silver suspension with a binder was firmly adhered onto gypsum surfaces. Scratch and ink tests were also found to be successful for the material.

Key Words

Architectural material, Coating, Submicro-Ag particles, Antibiotic test, Functional test

배성진 Sung Jin Bae , 나제현 Je Hyun Nah , 전은정 Eun Jeong Jeon , 서동천 Dong Cheon Seo , 김용진 Yong Jin Kim , 이동훈 Dong Hoon Lee

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Abstract

For estimation of methane gas generation in municipal solid waste landfill, IPCC(Intergovernmental Panel on Climate Change) recommended using FOD model that is based on First Oder Decay equation and presented a default value for parameters. Especially a default value for DOC(f)(Fraction of Degradable Organic Carbon which decomposes) have problems that is not based on experimental data, and is not considered for loss with leachate. Therefore, this paper estimated DOC(f) included leachate loss of DOC(Degradable Organic Carbon) by DOC balance analysis in SUDOKWON Landfill Site 1 was the largest landfill in Korea. As a result, DOC(f) is a range of 0.56 to 0.59 from 1992 to 2000 and this values are higher than IPCC default value(0.5). From DOC balance Analysis, 57.1% of total disposed carbon is emitted by gaseous carbon(CH₄) and 0.4% of that lost with leachate in SUDOKWON Landfill. DOC loss through leachate was less than 1% and this may be neglected for estimation of DOC(f).

Key Words

Landfill, Methane, FOD Model, DOC, DOC(f)

정진도 Jin Do Chung , 함기용 Ki Yong Ham , 권영석 Young Seok Kwon

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Abstract

A Solid Oxide Fuel Cell (SOFC) has a wide scope of operating temperature from 500 to 1,000℃, does not require any complex device which circulates carbon dioxide as in the case of Molten Carbonate Fuel Cell (MCFC) and does not have a problem of corrosive electrolyte continuously corrosion electrodes and other parts in high temperature. In this study, we composed a simulated gas by examining the data of biogas composition and studied electrical characteristics of SOFC. Also, we compared electrical characteristics of SOFC using methane and hydrogen. The result of measuring the electric characteristics of fuel cell using only hydrogen showed 1.05 V output when the current was 0.1 A. As to the electric characteristic of the fuel cell measured using simulated gases, the biogas of Asan-si environment center which was investigated to contain the biggest content of methane showed the highest value of 0.95 V (current 0.1 A) and Suncheon manure biogas which has low content of methane and high content of carbon dioxide showed the lowest value of 0.75 V (current 0.1 A).

Key Words

Biogas, SOFC, Methane, Electrical characteristics

김대용 Dae Yong Kim , 정병길 Byung Gil Jung , 최영익 Young Ik Choi

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Abstract

The noise was a sensible pollution that has disappeared after short period existences compared with other environmental pollution. However, invisible noise pollution was underlined as treatments technology improvement for air, water and soil pollution. Noise pollution is appeared as increasing noise source contact frequency and accumulating damages. Noise pollution gives various effects on human emotion, feelings and a physiological function. Therefore, a counterplan for reduction of noise pollution is necessary. Therefore, the reduction countermeasure for noise source is primary controlling, secondary controlling is noise occurrence and receiving source, third countermeasure is controlling about noise receiving source. The noise reduction of the most effective method is the secondary countermeasure, not the primary countermeasure by technology and costs. The secondary countermeasure is using the greatest number of porosity absorbent or insulation for a controlling method between the noise occurrence source and the noise receiving source. Efficiency, economic performance and productivity for the porosity absorbent which is made of glass fiber and rock wool is excellent. However, it is real condition that use is limited by human body risks and environmental restriction. Often polyurethane, polyethylene of foaming risen type and polyester of fiber type are used by these constraints but they have shortcoming that do not reach to the glass fiber and rock wool in economic performance and efficiency. Therefore, in this study, I wished to grasp development possibility of waste resources as an absorbent which was investigated to overcome constraint in efficiency and economic performance. Specimen was made to test absorption characteristics. The absorption characteristics of the specimen were measured in 10 Hz ~ 6,300 Hz by 1/3 octave band using two microphones in an impedance tube. The specimen was made of fly ash, bottom ash, sewage carbide, steel slag and waste building materials in considering specimen`s physical·chemical special quality. The porosity specimen has different properties according to used materials and manufacture methods. Therefore, development possibility of the waste materials as sound-absorbing materials is seen.

Key Words

Absorption coefficient, Absorbent, Waste plastic, Melting slag, Impedance tube

조성진 Sung Jin Cho , 이장수 Jang Su Lee , 이기배 Ki Bae Lee , 서용칠 Yong Chil Seo , 김보생 Bo Saeng Kim

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Abstract

The recycling steps of cathode ray tube (CRT) glass waste dismantled from a television (TV) set are composed by collection, separation of panel and funnel, crushing, and washing. CRT glass waste recycling is not well practiced because the transferring TV transmission to high definition (HD) from December 2012 and the shutting down of domestic CRT manufacturers in Korea. In this study, to promote recycling of CRT glass waste which is expected to the increment of generation after such shift of TV transmission method, selected recycling technologies were examined. In addition, draft road map of CRT glass recycling waste was revised and presented with defining the role of producers, recycling centers and government. In CRT glass waste, technologies of panel examined are cement brick, clay brick, and glass wool, and those for funnel are glazing and lead-smelting. As results of cement brick and clay brick in lab-scale tests, the entire samples satisfied the Korean Standard. To apply CRT glass waste recycling at existing technology it was suggested that facilities need to separate panel and funnel glasses exactly and to classify fine sizes after crushing glasses. Roadmap to future recycling strategy was suggested explaining the role of stakeholder to promote CRT glass waste recycling. Producer needs to establish market infrastructure with supply networking of CRT glass waste and to make monitoring system for environmental problem and the government needs to support R&D and reformation of the recycling system.

Key Words

CRT, Cathode-Ray Tube, waste glass, Recycling, Panel, Funnel

최보람 Bo Ram Choi , 김영석 Yong Suk Kim , 이원태 Won Tae Lee , 강성원 Sung Won Kang , 이태윤 Tae Yoon Lee

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Abstract

This study was performed to evaluate characteristics of illegally dumped construction wastes in the riversides of Nakdong river. We tried to determine whether these construction wastes contained toxic compounds and stabilized. Wastes were found at 4 sampling points and these wastes were not classified as toxic wastes. Instead, these wastes were classified as construction wastes. In addition, these construction wastes were not contaminated by toxic heavy metals, anions, and organic compounds according to soil pollution guidelines. Thus, these construction wastes can be recycled or treated as construction wastes according to the guideline provided by Korea Ministry of Environment.

Key Words

Nakdong River, Construction Wastes, Soil Pollution, Heavy Metals, Organic Compounds