최명수 Myung Soo Choi , 이우식 Woo Sik Lee , 이재동 Jae Dong Lee

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Abstract

Waste oil contains free fatty acids, impurities and water. However, the quality of raw materials should be remained constantly to produce outstanding biodiesel. In this study, due to changes in acid value of waste oil into biodiesel was undertaken to determine the characteristics of the transition. The trans-esterification reaction, an essential part of the biodiesel manufacturing process, was performed using waste oil, methanol, and alkali catalyst. We tried to deduce the optimum conditions by defining the operating variables, such as the acid value of waste oil, methanol/waste oil mole ratio and the reaction temperature. The biodiesel yield and fatty aicd methyl ester (FAME) content was decreased as the acid value of waste oil was increased. The optimum acid value of waste oil was 2.0 mgKOH/g at the temperature of 55℃, and methanol/waste oil mole ratio of 9.

Key Words

Biodiesel, Waste oil, Acid value, FAME content, Biodiesel yield

이태윤 Tae Yoon Lee

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Abstract

This study aimed to determine physico-chemical properties and biochemical methane production potential of sediments collected from Geomundo harbor. All samples consisted of similar ratio of C, N, S, and H. Ignition loss (%) ranged between 8.3 and 10.8, which indicated all samples had high amount of organic matter. Moderate amount of methane were produced from all tested samples. Cumulative methane production (mL) reached to 20.84 mL per gram of volatile solids. Empirical equations were made to estimate methane production using two parameters such as ignition loss and C/N ratio. In this study, C/N ratio explained methane production better than ignition loss. From this study, we found that sediments in Geomundo harbor could possibly emit methane gas to atmosphere, which resulted in global warming even though the quantitative contribution of the harmful effect was not estimated at this stage.

Key Words

Geomundo harbor, Elemental analyses, Ignition Loss, Sediments, Methane production potential

박진규 Jin Kyu Park , 정새롬 Sae Rom Jeong , 김경 Kyung Kim , 윤석표 Seok Pyo Yoon , 이병선 Byung Sun Lee , 이남훈 Nam Hoon Lee

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Abstract

The objective of this research was to assess the aerobic biodegradability of landfilled solid wastes using a large-scale respirometer of 17.7L, The large-scale respirometer was designed to measure the oxygen uptake rate for landfilled solid wastes with different landfill ages (2 year, 8 year, 14 year, 18 year, 20 year hereinafter called as ``A, B. C, D, E Landfill`` respectively). The cumulative oxygen uptake and oxygen uptake rate were highly influenced by landfill age. In terms of cumulative oxygen uptake. A landfill was the highest (14.87mg O2/g DM). followed by B landfill (8.30mg O2/g DM), C landfill (5.99mg O2/g DM). D landfill (2.47mg O2/g DM) and E landfill (1.74mg O2/g DM). Also, in this study, a logistic equation was suggested to simulate the cumulative oxygen uptake and oxygen uptake rate for landfilled solid waste. The logistic equation was statistically sufficient to simulate the cumulated oxygen uptake and oxygen uptake rate.

Key Words

Solid waste Landfill, Large-scale respirometer, Aerobic biodegradability, Oxygen uptake rate

이병관 Byung Kwan Lee , 이병기 Byung Ki Lee , 박영규 Young G. Park

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Abstract

Several investigation has done at the characteristics of decomposition of textile wastewater using advanced oxidizing treatment based on the ozone and electromagnetic process. The roles of electromagnetic radiation were studied to reduce the sludge amount of wastewater because of reducing the conventional use of FeCl2 in the Fenton`s oxidation, The motivation of this investigation is first to explore the feasibility of enhancing the wastewater treatment in the ozonation and the electromagnetic radiation. Membrane filtration in the chemical wastewater was finally tried after pretreatment by the chemical oxidation of ozone and the radiation of electromagnetic wave. Combination of both methods into a single process could be often an attractive alternative to remedy the inherent disadvantages of wastewater treatment. The purpose of this work is to reduce over 60% of produced sludge and to reduce over 30% of facility site-area by the combined ozonation, the radiation of electromagnetic wave and membrane process to address over 90% removal efficiency of wastewater in comparison with that of Fenton`s oxidation. The combined treatment process does offer considerable advantages unrealized by each of them.

Key Words

Ozone, Electromagnetic radiation, Textile wastewater, Sludge reduction

이성수 Sung Su Rhee , 강준구 Jun Gu Kang , 김규연 Kyu Yeon Kim , 전아현 Ahh Yeon Jeon , 차준석 Jun Seok Cha , 오길종 Gil Jong Oh

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Abstract

In this study, the feasibility of the biogas production by anaerobic digestion of the agricultural residues, which are stems and leaves of hot pepper or sweet pepper from one of the agricultural villages in South Korea, was investigated. Three components (moisture, volatile portion and ash) analysis was performed to characterize the basic property of the agricultural residues and the ultimate element (C, H, O, N and S) of the test material was analyzed to estimate the theoretical biogas production by anaerobic digestion. The formulas based on the stoichiometry of methane production were used to estimate the theoretical amount of biogas production from the agricultural residues, and the potential electricity of biogas from the agricultural residues was estimated. The results showed that the appropriate C/N ratio for anaerobic digestion was found with the agricultural residues, and hot pepper and sweet pepper could theoretically produce 365 L/kg VS and 326 L/kg VS of methane, respectively. The potential electricity of biogas generated from the agricultural residues was estimated to be 1,428 kWh in a day and the electricity of 157 families (63% of the total families) in the target area could be supplied. The electricity of all the families in this area could be supplied if the anaerobic digestion of food waste is added to that of the agricultural residues. In this case, the profit of 79,507 won/day could be made by selling the electricity remained after family supply.

Key Words

New & renewable energy, Biogas, Organic waste, Agricultural residue, Anaerobic digestion

김영민 Yeong Min Kim , 문용철 Yong Cheol Moon , 김재영 Jae Young Kim

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Abstract

Among organic components of waste, paper influences most significantly on the quantity of methane produced from landfilled wastes. However, there are many different types of paper and the biodegradabilities of them are not identical. The objective of this study is to measure methane generation potential and biodegradability of different types of paper most commonly used in Korea. Corrugated cardboard, newsprint, office paper, coated paper, recycled office paper and disposable diapers were selected and Biochemical Methane Potential (BMP) test was carried out to measure their methane production potentials. The maximum methane production was in a range of 141 and 332 mL-CH4/g-VS and the biodegradability was in a range of 21 and 84% depending on paper species. Both the methane generation potential and the biodegradability of office paper were the highest and those of disposable diapers were the lowest among six types of paper. The holocellulose and lignin contents were considered to cause the differences of methane production potentials among the papers studied.

Key Words

Methane yield, Biodegradability, Paper, Anaerobic digestion, Lignocellulose

탁봉열 Bong Yul Tak , 탁봉식 Bong Sik Tak , 민길호 Gil Ho Min , 이원구 Won Ku Lee

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Abstract

This study was to investigate H2S removal from biogas which is generated by plant using livestock manure. High removal efficiency (95.66%) for H2S was retained by using renewable ion exchange fiber during three month. The roles and optimal conditions of five independent variables including total livestock manure dose (X1), NaOH dose (X2), pH (X3), contact time of ion exchange fiber (X4) and outside temperature of plant (X5) were examined by multiple regression. According to ANOVA(analysis of variance) and t-test statistic, the predicted values of H2S removal was found to be in good agreement with experimental values (R2: 0,967 and Ra2: 0.958). X2, X3 and X4 were the positively significant variables (p<0.01). However, X1 and X5 had less significant impact (p>0.05). The predicted maximum removal efficiency for H2S was 99.99% when predicted optimum variables of X1: X2: X3: X4: X5 were 8 ton: 0.74kg: 13.237: 13.92 Nm3/h: 30. Our results imply that the multiple regression analysis can help identify the most significant operating factors for H2S removal in pilot scale as well as the reusable ion exchange fiber can be used to effectively remove H2S from biogas.

Key Words

H2S, Ion-exchange fiber. Pilot scale, Multiple regression

정다위 Da Vid Chung , 윤정인 Jung In Yoon , 김민선 Min Sun Kim , 유혜영 Hye Young Yu , 임진흥 Jin Hong Im , 김용준 Young Jun Kim , 박호연 Ho Yeun Park , 조준호 Jun Ho Cho , 김교근 Kyeo Keun Kim , 한상오 Sang Oh Han , 신선경 Sun Kyoung Shin , 오길

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Abstract

Waste timber from railroad is usually discarded or recycled as material for landscaping after 10 to 15 years. In order to extend the life of timbers, creosote oil is used which is a liquid, black-brown substance. This oil extracted from coal tar or vapor gas from wood combustion has been used as antiseptics long before 1900. In Korea, creosote oil is regulated as a wood preservative in the notice of the National Forest Research Institute. It is very effective and consists of a variety of organic compounds which are mostly Polycyclic Aromatic Hydrocarbons (PAHs). In this study, the hazardous substances like oil, BTEX, PAHs, phenols, etc. have been analyzed. Oil is a substance which is extracted by n-hexane. It is basically used to quantify the extract of waste timber and to establish a relationship to other substances like PAHs. BTEX are benzene, toluene, ethylbenzene and xylene. PAHs is the abbreviation for Polycyclic Aromatic Hydrocarbons which are well known to occur in high concentration in creosote oil. In this study, we analyzed 16 compounds of PAHs including Benzo(a)pyrene(BaP). Phenols comprised 21 compounds including PCP (PentaChloroPhenol) which is regulated as soil contaminant. We hope this study will be helpful to understand hazardous substances in waste timber and will contribute to an appropriate management before recycling the waste.

Key Words

Waste, Timber, Rail Road, Creosote, PAHs, BTEX, Phenols, Oil

이모권 Mo Kwon Lee , 김동훈 Dong Hoon Kim , 임소영 So Young Lim , 김미선 Mi Sun Kim

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Abstract

In the present work, the biogas production potential of star-fish waste was estimated using response surface methodology (RSM). After grinding and centrifugation of star-fish waste, only the supernatant was used as a substrate. The supernatant contained 55% of total COD in the whole feedstock. Sixteen experimental sets for biochemical methane potential (BMP) test were made according to central composite design at various inoculum/substrate (I/S) ratios, substrate concentrations (2.0~8.0g COD/L), and buffer capacities (0-5g NaHCO3/L). Methane yield (MY) increased as 1/S ratio increased and substrate concentration decreased. By applying regression analysis, MY was well fitted based on the actual value to a second order polynomial equation (p=0.0110): Y = 251.81 + 54.59X1 - 8.46X2 + 13.09X3+ 2.29X1X2 - 7.25X1X3 + 4.90X2X3 - 8.24X1(2) - 1.10X2(2) - 4.38X3(2), where X1, X2, X3, and Y are I/S ratio, substrate concentration, buffer capacity, and MY, respectively. The highest MY of star-fish was estimated to be 334 mL CH4/g COD, accounting for 52% of energy content in the feedstock.

Key Words

Star-fish waste, Response surface methodology, Inoculums/substrate ratio, Methane yield, Buffer capacity, Substrate concentration

김상근 Sang Keun Kim

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Abstract

Waste wood contained in construction waste would possibly be used as a fuel or recycled material in other industries. The combustible materials including paper, textile, plastic, vinyl or synthetic resins could be used as subsidiary fuel or recycled material. In this study, an air-knife gravity separator was used to separate the wood from the combustible waste generated from the construction waste. Air-knife gravity separator was designed to separate the wood which is heavier than air and small combustibles which is lighter with lower than air, Certain air pressure is maintained in the inclined conveyor to separate heavy wood particle from light combustibles. The investigation results shows that the sorting/separation efficiency depends on angle of inclination of the conveyor. About 80% of wood was dropped to the bottom at 30.4~32.25° and more than 70% of vinyl, plastic, paper and textile were lifted up so that the wood with higher density and the combustibles with lower density were separated. Given that more than 90% of waste wood was dropped at conveyor speed 13.4 m/min or more, conveyor speed needs to be adjusted to 13 m/min at least for separating the woods.

Key Words

Construction waste, Wood recovery, Gravity separator, Air-knife

이승희 Seung Whee Rhee

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Abstract

The mechanism of reaction kinetics of sewage sludge is investigated by conversion in carbonization process. In the carbonization process, carbonization time is changed from 5 min. to 60 min and carbonization temperature is varied from 250℃ to 400℃. As increase carbonization time, conversion of sewage sludge is increased sharply for initial 5 min. and increased slowly after 5 min. From the examine of conversion of sewage sludge in carbonization process, carbonization reaction can be expressed by the reaction kinetics. As increased carbonization temperature, reaction rate constant and frequency factor in the Arrhenius equation were increased. C/H mole ratio is also increased with increasing carbonization temperature. In order to have a reliable stability of the carbonization residue, carbonization temperature should be less than 350℃. The activation energy of carbonization for sewage sludge can be decided by 2,644.5 kcal/kmole.

Key Words

Carbonization. Sewage sludge, Conversion, Reaction rate constant

손영금 Yeong Geum Son , 이우근 Woo Keun Lee

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Abstract

In this work, paste was made from MSWI (municipal solid waste incineration) bottom ash and slag by geopolymer technique. The effect of mixing ratio of sodium silicate and potassium silicate on its physical property was evaluated. The specimens were cured at 50℃ for the period of I, 3, and 7 days. The compressive strength of cured samples were measured. Compressive strength was decreased with the addition of potassium silicate. Maximum value of 55.9 MPa was obtained at mixing ratio of 95 : 5. From mixing ratio of sodium silicate and potassium silicate, leching results of Si, Al. Ca ions were appeared difference. At mixing ratio of 95: 5, leaching of Ca ions was decreased the most. As a result, depending on the concentration of leaching ions change compressive strength.

Key Words

Sodium silicate, Potassium silicate, Compressive strength, Leaching test

나춘기 Choon Ki Nat , 송명기 Myoung Ki Song

DOI:

Abstract

In order to study on the utilization of residual waste from extraction of onion juice as an alternative feedstock for bioethanol production, the acid hydrolysis of the residual waste to fermentable sugars and their fermentation process to ethanol as well as ethanol yield was investigated. The acid hydrolysis enhanced the yield of reducing sugars for fermentation and thus led great increase of ethanol productivity. The maximum concentration of reducing sugars in the hydrolysate reached 45 g/L under the optimal condition of dilute sulfuric acid-hydrolysis (0.5%(w/v), 120℃. 1.0h). After fermentation by Saccharomyces cerevisiae at 35℃ for 12h, the ethanol concentration reached 40 g/L, which corresponds to approximately 1.7 times higher than the theoretical yield from total reducing sugars in the hydrolysate. It indicates that some components like scorodose and allyl disulfides in onion was decomposed into fermentable sugars by acid hydrolysis. The ethanol productivity from the hydrolysate increased with increasing the dosage of yeast up to 8.0 g-dry/L and then leveled off. The ethanol yield estimated was approximately 5,280kg/ha/year, and indicated that onion waste (or law onion) is a potential feedstock for bioethanol production.

Key Words

Bioethanol, Acid hydrolysis, Reducing sugar, Fermentation, Onion

조성진 Sung Jin Cho , 정해영 Hae Young Jung , 이기배 Ki Bae Lee , 김우현 Woo Hyun Kim , 서용칠 Yong Chil Seo

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Abstract

The present technology to handle ELVs (End-of-Life Vehicles) usually generates about 20-30% of the automobile shredder residue (ASR) based on a new car in weight. A plastic fraction consisting mainly of urethane/styrofoam waste is generated after separating valuable spare parts and metals from used electrical home appliances. In Korea, such waste is currently incinerated in cement kilns or dumped into landfill. Some appropriate technologies to treat such synthetic resin from automobile shredder residue (ASR) and E(electronic)-waste are not ready to reduce up to the target set in the national law. One of the candidate technologies with zero emission and better public acceptance with converting wastes to energy could be gasification or pyrolysis. In this study, synthetic resin sampled from a domestic shredding company of ELVs and recycling center of home appliances was experimented on at a lab-scale gasification and melting process. Tests have been conducted at various experimental conditions such as equivalent air ratios (ERs) to observe yields of products, syngas composition, heating values and carbon conversion. The attempts and results to treat ASR from end of life vehicles and E-waste from electronic appliances by gasification techniques in a lab scale experimental set-up to design a commercial gasification plant.

Key Words

End-of-Life vehicles, ELVs, Automobile shredder residue, ASR, Urethane/styrofoam, Electrical appliance waste, E-waste, Gasification

조성진 Sung Jin Cho , 정현태 Hyun Tae Joung , 정해영 Hae Young Jung , 유흥민 Heung Min Yoo , 서용칠 Yong Chil Seo

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Abstract

In accordance with extension of waste pyrolysis/gasification/melting plants, various technologies for recycling of melting slag generated from such melting process are proposed. In this study, we evaluated the reusability of melting slag generated from a pilot-scale gasification and melting plant as heating asphalt mixture aggregates. As results of analyzing characteristic for recycling a fine aggregate, the stability, density of saturated surface dry condition, and absorption were satisfied to their standards excluding fineness modulus. After investigating the optimum condition of slag content in mixed asphalt, the mixture ratio showed that amount of the broken stone of 13 mm, screenings, melting slag, sand and filer are 61%. 6%, 10%. 15% and 8% respectively. The optimum asphalt content (OAC) was from 4.7% to 5.2%. Less amount of asphalt can be used in case of slag containing in the mixture when compared with the normal asphalt mixture without slag. The results of marshall test, indirect tensile strength test resilient modulus test, wheel tracking test of asphalt mixture with slag were fulfilled to the standards, If similar research had been proceeded continuously, it was considered that melting slag can be applied to actual heating asphalt mixture.

Key Words

Gasification, Melting slag, Recycled aggregate. Asphalt paving