정재우 Jae Woo Chung , 변염철 Young Chul Byun , 조무현 Moo Hyun Cho

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Abstract

This review describes the current status of the thermal Plasma gasification/vitrification technology for waste treatment. A broad range of survey including literatures, reports, patents, and websites was carried out. Thermal Plasma gasification/vitrification technology is estimated to be a viable alternative for the waste treatment. The technology is more environmentally friendly compared with the conventional incineration in considering the efficiency, environmental impacts, energy recovery, etc. However, the economic feasibility needs to be elucidated and energy recovery, methods should be established to spread out the application. It is expected that the application of thermal plasma gasification/vitrification will expand to treat wastes along with the increase of global energy demand and concerning about global climate change.

Key Words

Plasma gasification/vitrlfication, Waste treatment, Energy recovery, Economic evaluation

박상우 Sang Woo Park , 장철현 Cheol Hyeon Jang

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Abstract

After sewage sludge generated from the treatment process of municipal sewage was carbonized, the fuel characteristics of carbonized sludge were investigated and its results are as follows. As carbonization temperature increased, fuel ratio increased, generation yield and calorific value reduced, and the fuel rank by coal band characteristics improved. In the combustion characteristics by combustion profile, ignition temperature (Ti) improved as carbonization temperature increased, and combustion time(t(p)) shortened. Hardgrove Grindability 1ndex (HGl) increased as fuel ratio increased, and showed high value than RS. Also in the result of FT-IR, aliphatic C- H bond and O-H bond by fuel reforming were decreased.

Key Words

Fuel reforming, Carbonized Sludge, Fuel characteristics, Co-combustion

장신요 Shin Yo Jang , 정연구 Yeon Koo Jeong

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Abstract

The effects of retention time in gravity thickener on the dewatering and conditioning properties of sludges were investigated using settling column of working volume 58 L. Two kinds different water treatment sludges were used, one was taken from the plant treating dam water and the other was from the Plant treating river water SRF was used to evaluate the dewaterability of sludges and two kinds of anionic polymers were used in conditioning experiments of each sludges. The dewaterability of sludges judging from the SRF was improved for the first 5 days in gravity thickening regardless of the sludges. After that, no decrease in SRF (specific resistance to filtration) was observed. An improvement of dewaterability was also confirmed by the measurements bound water content in sludge. The demand of polymer in conditioning was increased with a increase in retention time. Water quality of filtrate was also deteriorated as duration in thickener increased. Further research including the analysis of water content in sludge cake would be needed to investigate the effects of retention time in thickener on sludge dewaterability clearly.

Key Words

Gravity thickener, Retention time, Conditioning, ning, Specific resistance to filtration, Water treatment sludge

김태은 Tea Eun Kim , 정재아 Jae A Jeong , 이우근 Woo Keun Lee

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Abstract

With the advance of industrialization and urbanization, a lot of waste has been discharged and treated by incineration. In Korea, 441, 004 ton of MSWI fly ash is discharged, which is composed of bottom ash (about 450, 327 ton) and fly ash (about 92, 755 ton) in 2008. MSWI fly ash generally contains high content of heavy metals, so it is regarded as hazardous waste. The objective of this research is to prepare brick made from waste materials such as MSWI fly ash, water sludge and coffee sludge. in this study. The optimum mixing ratio for these materials were 19. 5%: 19. 5%: 1%: 60% respectively. They were dried at room temperature for 48 hrs, and heated for 4 hrs at 60℃ and for 6hrs at l00℃. After that, the dried bricks were sintered at 5℃/ min to l， 115℃, and kept for 2 hrs at that temperature. Maximum compressive strength was 19.1 MPa at the optimal condition in our study.

Key Words

MSWI fly ash, Coffee sludge, Brick, Compressive strength, KSLT

김태승 Tae Seung Kim , 김광호 Kwang Ho Kim , 한규섬 Gyu Seong Han , 최인규 In Gyu Choi , 최준원 Joon Weon Choi

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Abstract

In this study, biodiesel was produced with oils (fats) extracted from spent coffee grounds by alkaline transesterification reactions using sodium hydroxide as catalyst. For comparison, Jatropha seed (Jatropha curcus), which is typical raw material for biodiesel, was also subjected to the same experimental procedure. As intermediate for biodiesel production the oils were extracted from the two materials by two methods; soxhlet extraction and stirring extraction. In two ways of extraction, 13.4% and 10.7% of oils based on dry weight of material were obtained from spent coffee ground, respectively, and 33.1% of oil was obtained from Jatropha seed by stirring extraction. Although the oils extracted from Jatropha seed were totally converted to biodiesel by alkaline transesterification, the conversion rate to biodiesel was ca. 50% for the oils extracted by soxhlet method and 75% for the oil extracted by stirring method. Irrespective of extraction methods the biodiesel derived from the coffee grounds was mainly composed of palmitic acid (Cl6: 0; 40.9%) and stearic acid (C18: 0; 8.5% ) as saturated fatty acid as well as oleic acid (C18: 1; 14.7% ) and linoleic acid (C18: 2; 32.9%) as unsaturated fatty acid. Compared with biodiesel from Jatropha seed, the feature of the biodiesel from spent coffee ground was relatively high portion of saturated fatty acid (over 50%).

Key Words

Spent coffee grounds, Jatropha seed, Alkaline transesterification, Fatty acids

박진수 Jin Soo Park , 문태영 Tae Young Mun , 김주식 Joo Sik Kim , 리광훈 Gwang Hoon Rhee

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Abstract

In this paper, a computational fluid dynan1ics (CFD) model was developed for woody waste in two-stage fluidized bed gasifier using Star-ccm+ ver. 4. 02. Gasification processes were solved through hybrid kinetics/EBU model that includes the arrhenius equation in order to add the effects of chemical kinetics. The effect of activated carbon was simulated using the tar elimination process modeling. Effects of equivalence ratio (ER), temperature of gasifier, with and without activated carbon on the gas composition of producer gas were studied. Numerical predictions were compared with experimental results and represented good agreement.

Key Words

Computational fluid dynamics, CFD, Fluidized bed gasifier, Two-stage, Woody waste

손세구 Se Gu Son , 김영도 Young Do Kim

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Abstract

This Paper investigates the thermal stability and mechanical properties of geopolymer mortar prepared using sand, coal fly ash, blast furnace slag and alkaline activator. The geopolymer mortar have been found to possess good thermal stability. Compressive strength and weight loss, water absorption, density, PH value were depends on the firing temperature. The Compressive strength of geopolymer mortar fired at 200℃ exhibits higher value (70.0 MPa) and decreased along with increasing temperature until 700℃. When the geoplymer mortars are fire treated in a temperature range from 800℃ to l, 100℃, it is found that mechanical properties can be greatly improved. From 200~700℃ shows weight loss due to both evaporation of free water and condensation of hydroxyl groups. XRD patterns indicate the fact that geopolymer mortar up to 600℃ is composed of amorphous aluminosilicate phase and calcite, quartz. Crystallization of geopolymer mortar starts at a low temperature ~800℃ according to XRD. Its amorphous structure being replaced by the crystalline feldspars albite and leucite at 800℃. In FT-IR spectroscopy, the main peak about 1000 cm-1, 700 cm－1 and 450 cm－1 have been attributed to network Si-O-Si (or Si-O-Al) bending band. SEM observation shows that it is possible to have density and many pore microstructure forming within geopolymer mortar at different firing temperatures.

Key Words

Geopolymer mortar, Thermal stability, Crystallization, Albite, Leucite

한섬국 Seong Kuk Han , 윤회관 Huy Kwan Yun , 김진혁 Jin Hyok Kim , 안대현 Dae Hyun Ahn , 김재용 Jae Yong Kim

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Abstract

Dumping of wastes at ocean 15 strongly prohibited from 2012 by London Dumping Convention. So, treatment of food waste leachate at ground is needed urgently. As the solution for above mentioned problem, we suggest the food leachate resources by using Upflow Anaerobic Sludge Blanket(UASB) process. The aim of this study was evaluate organic concentration and hydraulic retention time (HRT) influence in COD removal effciency and biogas production using food waste leachate in UASB reactor. The COD removal efficiency was above 85% and methane yield show 78 ~ 84% in operating time. Biogas production rates show 0.27 to 0.52 m3/kg CODrem. as (Organic Loading Rate) OLR was increased from 2 to 40kgCoD/m3 · day. Final1y, we got the conclusion that it is more effective operation result with short HRT at low concentration than with long HRT at high concentration in the UASB process.

Key Words

Food waste Leachate, UASB process, Anaerobic digestion, Granular sludge, Biogas

천승규 Seung Kyu Chun

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Abstract

The influence of the uncertainty in input factors of first order decay model on the reliability of modelling results was analyzed for SUDOKWON Landfill site 2. The total CH4 generation amount from 200l to 2035 by modelling was 4.46 x 10(9) Nm3. Among the uncertainty influences of waste on total CH4 generation, Paper showed the biggest value of 45.6%． And among that of L. W and k, k showed the smallest value of 9.5% , but as medelling perieds were shortened the influence became bigger. Monte Carlo Method was applied to analyse the influence of uncertainty of L, W, K on modelling value. 5,000 times of calculation was done by random number generation of uniform distribution and tw0 kinds of normal distribution. The probability to excess over 20% in the differences between modelling and real value was 38.9% in uniform distribution, 24.7% in normal distribution (U.R.=6σ) and 43.6% in normal distribution (U.R.=4σ) .

Key Words

Landfill gas, First order decay model, Uncertainty analysis, Monte carlo method

이명호 Myung Ho Lee

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Abstract

A series of laboratory column tests were performed to investigate desorption processes of heavy metal contaminant from clayey soil· subjected to a DC electric field. Research focused on the removal eff1ciency and contaminant migration through porous media by the combined effects of electro-migration and electro-osmosis during electrokinetic soil processing. The correlations of the applied electric field strength, electro-osmotic flow rate, and the resultant ion concentration are investigated and evaluated. The results showed that the removal efficiency was high during the early stage of processing due to the rapid desorption by the effects of electrokinetics in the cathode region.

Key Words

Electrokineties, Zinc, Desorption, Kaolin, Removal efficiency

김규용 Gyu Yong Kim , 최형길 Hyeong Gil Choi , 신경수 Kyoung Su Shin , 나철섬 Chul Sung Na , 박선규 Sun Gyu Park , 이도헌 Do Heun Lee

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Abstract

As recycled fine aggregate manufacturing technology with exceeding in economical efficiency, reduction efficiency of environmental load and quality improvement effect of recycled fine aggregate, it is to develop dry manufacturing system composed specific gravity separator of high-speed rotation impact type and centrifugal Force Powder Collector, etc. in this study. And it is to verify performance with evaluating quality of recycled fine aggregate. In consequence, it is identified that performance improvement effect of recycled fine aggregate by crushing recycled fine aggregate according to high-speed rotation impact, separating and collecting powder and minuteness dust according to centrifugal Force and mass defect, separating and reclaiming minuteness sand to mass defect.

Key Words

Waste concrete, High speed impact, Higher value-added, High quality recycled sand, Dry manufacturing system

유재인 Jae Min Yoo , 이재천 Jae Chun Lee , 정진기 Jin Ki Jeong , 장기석 Ki Seok Jang

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Abstract

Continuous exhaustion of resources and environmental aspect are considered as the key issues in enlarging the scope for the development of technology for the recycling of valuable metal from ever increasing end-of-life electric and electronic equipment. In the present study, characterization of used liquid crystal display (LCD) module and state-of-the-art recycling tec1lnology for valuable materials from obsolete LCD module from available literature including patent analysis are reported. Metal components such as gold, indium, tin, magnesium etc. that exist in LCD module give the value for recycling. Recycling technologies related to producing the intermediate product by primary treatment of end-of-life LCD, indium recovery and glass recycling appear to be the core technology for the recycling of such waste. A look at the literature related to waste LCD shows that the following process steps are promising: separation of polarizing plate, separation of substrate, recovery of liquid crystal, recovery of indium, removal of organic layer, and removal of inorganic layer.

Key Words

Recycling of liquid crystal display, LCD, Valuable materials, Recycling of glass, Recovery of indium