김낙주 Nack Joo Kim , 천승규 Seung Kyu Chun

DOI:

Abstract

A field research at Sudokwon landfill was carried to analyse the effect of leachate and organic waste water injection on decomposition characteristics of landfill waste. The moisture content after leachate (79,783 m3) addition into block 3A for 1 year increased from 27.4% to 34.1%. As a result of moisture increasement, Cellulose and Lignin proportions as indicators of waste degradability changed from 1.45 to 1.18. It is also illustrated that TOC as an indicator of CH4 production potential reduced from 22.0% to 19.5%. Comparison results of TOC after 4 months of each leachate, digested waste water, food waste water injection into block 4A shows reduction of 3.5%, 4.7% and 3.7%, respectively. Hence, it is indicated that injection of leachate and organic waste water into landfill enhances the rate of CH4 production as well as the speed of landfill stabilization.

Key Words

Solid waste landfill, Leachate, Waste decomposition, Lignocellulose, Total organic carbon

최항석 Hang Seok Choi , 박훈채 Hoon Chae Park

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Abstract

In this study, a cold model of a circulating fluidized bed is developed and tested for designing a char combustor. This study has been carried out to investigate effects of the solid circulation rate and superficial gas velocity on the hydrodynamic characteristics in a circulating fluidized bed. Solid holdup and pressure drop in the riser increases with the increase of solid circulation rate, but decreases with increasing superficial gas velocity. The solid holdup in the dense region increases with increasing solid circulation rate at lower gas velocities, whereas it is independent of solids circulation rate at higher gas velocities.

Key Words

Circulating fluidized bed, Solid holdup, Char combustor, Waste biomass

이은영 Eun Young Lee , 장인섭 In Seop Chang , 김종구 Jong Goo Kim , 이미향 Mi Hyang Lee , 홍선화 Sun Hwa Hong , 장재경 Jae Kyung Jang , 강연구 Youn Koo Kang , 유영선 Yong Sun Ryou

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Abstract

This study was attempted to evaluate the change of microbial community in inoculums, lag, and stationary phase using the community level physiological profiles (CLPP) base on C-substrate utilization. It was to ascertain the characterizing microbial community over time in the enrichment step of microbial fuel cells. Microbial fuel cell is a device that converts chemical energy to electricity with aid of the catalytic reaction of microorganisms using C-substrate included wastewater. Microbial fuel cells enriched by a mixture of anaerobic digestive sludge of the sewage treatment plant and livestock wastewater were used. The current after enrichment was generated about 0.84 ± 0.06 mA. Microbial community in inoculums, lag and stationary phase used amine group, phosphorylated chemical group, and carboxylic acid group (some exclusion). However, phenolic compound did not use by microorganisms in lag and stationary phase. It means that there are not the microorganisms capable of decompose the phenol in microbial fuel cell enriched by livestock wastewater. In case of substrates of amino acid and carbohydrates group, these C-substrates were only used by microorganisms in the stationary phase. It may be that electrochemically active microorganisms (EAM) which we want to know should utilize the better these C-substrates than that of lag phase. This study showed that the electrochemically active bacteria that can be distinguished by electron changes of C-substrate utilization over time could be separated.

Key Words

Microbial fuel cell (MFC), Eco-plate, Livestock wastewater, Carbon-substrate utilization

이수영 Soo Young Lee , 김삼권 Sam Cwan Kim , 석광설 Kwang Seol Seok , 이지윤 Jee Yoon Lee , 허종원 Jong Won Heo , 고윤화 Yun Hwa Ko , 정승열 Seung Ryul Jeong

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Abstract

The formation potential and pathway of less-chlorinated PCBs, including mono- and di-chlorinated biphenyls, was investigated when PCBs contained in transformer oil were dechlorinated by commercial treatment. Potassium hydroxide with polyethylene glycol (PEG-600) was used for dechlorination of PCBs, and its destruction efficiency to whole 209 congeners of PCBs was 97.1% on average, ranging from 95.6% to 98.2%. Homologue of mono-CBs showed the negative destruction efficiencies, while those of highly-chlorinated ones through tri- to deca-CBs showed better efficiencies than about 99%. In particular, mono-chlorinated biphenyl in meta-position (#2) was about 34-47 times enriched after dechlorination, thus the reactivity seemed to be in the order of ortho-, para-, and meta-chorinated biphenyl. Co-planar PCBs`` dechlorination efficiency was averaged as high as 99.4%, but 3,4,4``,5-TeCB (#81) showed a relatively lower efficiency than others`` in one case. Not only sodium metal but also alkaline metal such as potassium was thought of affecting the formation or enrichment of mono-chlorinated biphenyls produced by Wrutz-Fittig reaction as intermediates and products.

Key Words

PCBs, Transformer Oil, KOH/PEG, Dechlorination, Enrichment

김상범 Sang Bum Kim , 기광석 Kwang Seok Ki , 임동현 Dong Hyun Lim , 이현준 Hyun June Lee , 권응기 Eung Gi Kwon

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Abstract

This experiment was conducted to determine the effect of increasing the dietary levels of nattokinase (NK) addi-tives on milk production and composition, and blood metabolites in dairy cows. NK additives with high fibrinolytic activity were produced by the strain with similarity to the Bacillus amyloliquefacines. A total 20 mid-lactating Holstein cows (average body weight 652.00 ± 4.38 kg; average 2.25 ± 0.35 parity; average milk yield 24.4 ± 0.38 kg/d) were randomly assigned to three treatments (5 animals per treatment). Cows were fed TMR supplemented with DDGS 100 g for control, NK additives 100 g and 200 g for T1 and T2 treatment, respectively for 4 weeks. By the increases of NK additives, milk yield increased for T1 (1.35 kg/d) and T2 (0.98 kg/d) at the final period than at the initial period (p < 0.05). But milk protein content decreased for T1 (3.20%) and T2 (3.24%) than for control (3.56%) (p < 0.05). Blood triglyceride, T-CHO and BUN levels in T1 decreased compared with that in control and T2 (p < 0.05). This finding showed that 100g of NK additives could possibly have a positive effect in lactation performance of mid-lactation Holstein cows by increasing milk yield, improving protein metabolism and decreasing cholesterol in blood.

Key Words

Dairy cows, Nattokinase (NK), Milk production, Blood metabolites, Bacillus amyloliquefacines

김상범 Sang Bum Kim , 기광석 Kwang Seok Ki , 임동현 Dong Hyun Lim , 이현준 Hyun June Lee , 권응기 Eung Gi Kwon , 박중국 Joong Kook Park , 김태일 Tae Ile Kim

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Abstract

The study was performed to evaluate the effects of soybean meal (T1) and corn distillers dried grains with solubles (DDGS, T2) hydrolyzed by microbial proteolytic enzyme of Protame® on milk production and protein contents in dairy cows. Total of nine Holstein cows (i.e., 1.67 ± 0.47 average parity and 23.7 ± 1.2 kg/d average milk yield) were randomly assigned to control, T1, and T2 (e.g., 3 animals per group) and treated for 4 weeks. Milk yield of 3 different groups was similar in the beginning of the study, however the milk yield of T1 and T2 treatment group had increased by 0.93 kg/d and 1.89 kg/d, respectively. Milk protein level of T2 treatment group was increased by 0.19% (e.g., 0.14 kg/d protein content), whereas there was no significant different in control and T1 group. In conclusion, blood metabolites were ranged in normal level, but BUN content was reduced from 19.03 mg/dl to 17.70 mg/dl in T2 treatment group. This result suggests that DDGS hydrolysate supplement efficiently increase milk yield and milk protein level as well as feed protein availability in dairy cattle.

Key Words

Soybean meal, DDGS, Proteolytic enzyme, Dairy cows

이명호 Myung Ho Lee

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Abstract

The amount of contaminated dredged materials are increasing every year in Korea. Secondary contamination would be expected, if contaminated marine clayey slurry remains without treatment. Therefore, the appropriate remedial treatments are required in order to prevent secondary contamination. Electrokinetic method is especially suitable for low permeability dredged clayey soils because pore fluid can be easily transported by electric field. Hydrogen ions created by electrolysis enhance the remedial processes by desorbing heavy metal contaminants from slurry soil surfaces. This study investigated variation of electrical current and voltage gradient during the treatment, and ICP analysis as well as pH measurements were carried out to measure zinc concentration during and after the treatment.

Key Words

Electrokinetic, Remediation, Dewatering, Heavy metal, Slurry

박지선 Ji Sun Park , 전찬수 Chan Soo Jeon , 송태협 Tae Hyeob Song

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Abstract

Waste stone sludge generated during the collection of crushed aggregate is difficult to use due to high moisture content. Production of 1 ton aggregate generates approximately 0.25 tons of waste stone sludge. Considering the total crushed aggregate collection in 2012 of about 100 million tons, it can be estimated that 25 million tons of waste stone sludge is generated annually. Recycling of waste stone sludge is made difficult by the high moisture content of 30%. Therefore, to make recycling this process must be a drying process, which makes a fine powder of even better quality that can use as an additive. The purpose of this study is to analyze the changes in physical properties caused by the use of dried waste stone sludge as an additive in the extrusion of cement. A test specimen was made, substituting 50% of the silica with waste stone sludge, and physical performance evaluation was performed. Results showed that 50% substitution of silica resulted in no difference in moldability, but a slight increase in the water content required for the same workability was found. Flexural strength and drying shrinkage were found to be 97% of normal levels, but satisfied the specified performance in the KS F 4735 standard.

Key Words

Crushed stone powder, Extrution, Cement panel, C/S mole ratio, Silica powder

김규연 Kyu Yeon Kim , 강준구 Jun Gu Kang , 박준범 Jun Boum Park , 송영우 Young Woo Song , 이광헌 Gwang Hun Lee , 이성수 Sung Su Rhee , 우희수 Hee Soo Woo

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Abstract

The proper disposal of digestate from biogas plants has been focused while the use of biogas plants to treat organic waste has been considered as a way of green energy production. This study analyzed chemical and biological characteristics of two types of digestates from 6 domestic biogas plants for low cost and environmental recycling. The results showed that separated solids met current standard for compost within organic content, ratio of organic matter and NaCl concentration, although water content and maturity of separated solids did not meet the standard. Total content of N, P2O5 and K2O in separated liquids met current standard for liquefied fertilizer except that in separated liquids from sewage sludge, although NaCl content of separated liquids from food waste exceed the standard. Heavy metal content, coliform count and 2 kinds of harmful microorganisms were also detected below domestic standard for compost and liquefied fertilizer. These results suggested that digestates from biogas plants could be recycled to be fertilizer with additional treatment such as post-composting or salinity removal process.

Key Words

Digestate, Anaerobic digestion, Recycling, Biogas plant, Fertilizer

정태호 Tae Ho Jeong , 남궁완 Wan Nam Koong

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Abstract

The objective of this study was to evaluate the immobilization of heavy metals (Cu, Pb, Zn and Cd) in an abandoned mine soil by applying both soluble phosphates and steel slag as stabilizers. The application rate of stabilizers to soils was determinated based on PO4/Pb molar ratio of 2.0 for phosphates and on weight/weight ratio of 2, 5, 10% for steel slag, respectively. Immobilization efficiency of heavy metals in the contaminated soils was evaluated by toxicity characteristics leaching procedure (TCLP). After adding both phosphate and slag, the immobilization efficiencies of Cu, Zn and Cd increased significantly (about 14% - 40%) compared to those of treatment with soluble phosphate alone. The increae in immobilization efficiencies of Cu was the greatest. Whereas, immobilization efficiency of Pb was not significantly different from those with soluble phosphate alone. Among the tested three phosphates (Na2HPO4 ·12H2O, Ca(H2PO4)2 ·H2O, (NH4)2HPO4), the immobilization efficiencies with Na2HPO4 ·12H2O increased more than those of other phosphates. Results of sequential extraction analysis indicated that fraction of reducible form (F3) and residual form (F5) increased, while mobile forms (F1, and F2) decreased after immobilization treatment with both stabilizers resulting in decrease in leachability of heavy meyals in the treated soils. Residual fraction of Cu after treatnment was the highest as 68.5%, it was followed by Cu > Pb > Zn > Cd.

Key Words

Heavy metals, Immobilization, Steel slag, Phosphate, Sequential extraction

박성우 Sung Woo Park , 김한준 Han Jun Kim , 고진수 Jin Soo Ko , 김병윤 Byung Yun Kim

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Abstract

This study is to review its possibility of recycling, subject for Polyolefine (TPO) and Polyvinyl Chloride (PVC) among thermoplasticity plastic raw materials, of which recycling is possible. Wasted vinyl and processing by-products have been used for Polyolefine (TPO), and coating from used cable and its by-products used for Polyvinyl Chloride (PVC). The study result is shown as following. (1) In case of Polyolefine (TPO), superior property has been shown, when mixed with raw materials, as the property of by-products is excellent. For Polyvinyl Chloride (PVC), property in the same level as raw materials has been shown up to 50% of by-products mixing rates. (2) In case of coating from the used cable, the property as exactly same as raw materials without property loss has been shown since long time passed, with using highquality raw materials at that time of manufacture.

Key Words

Waterproofing sheet, Recycle, Used vinyl, Used cable, By-product

이재영 Jai Young Lee , 이병진 Byung Jin Lee , 조미현 Mi Hyun Jo

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Abstract

The refuse derived fuel (RDF) is available for renewable energy which can use alternative fuel to utilize recycling municipal solid waste (MSW). The RDF plant where can produce 100 ton/month of RDF, the largest manufacturing plant in Korea so far, were investigated in this study. The actual operated RDF yield showed 21.7% that was lower than expected yield; originally designed value was 25.0% in this plant. The cause of these results was that difference between physicochemical properties of MSW applied this plant originally and actual incoming it. The MSW affected to make separation efficiency of MBT process decreasing. It led to reduce amount of combustible material which needed for RDF after separating process. The each element of facilities was modified; decreasing width of the blade of a shadder from 110 mm to 63 mm, reducing the size hool of trommel screen to possible separating under 40 mm of MSW, increasing heat capacity of dryer from 2,000 Gcal/hr to 2,500 Gcal/hr, and conveyor type changed to prevent path MSW away during moving into each process and so on. After modifying facilities, got more combustible materials which were once lost and RDF yield increased to 30.9%. Whereas, low heating value of RDF was 4,725 kcal/kg, 0.8% of chlorine on average and other parameters were satisfied with domestic standard of RDF regardless of modifying MBT facilities.

Key Words

Refuse Derived Fuel (RDF), Mechanical Biological Treatment (MBT), Municipal Solid Waste (MSW), Physicochemical properties, Trommel screen

김양진 Yang Jin Kim , 채재우 Jae Ou Chae , 최지호 Ji Ho Choi , 김나랑 Na Rang Kim , 구재희 Jae Hoi Gu , 박영수 Yeong Su Park , 남상익 Sang Ick Nam

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Abstract

Korea has adopted a federal renewable electricity standard that begins at 2% in 2012 and requires companies to source 10% of their electricity from renewables by 2022. Therefore the interest in the use of biomass as a renewable energy resource is growing. By importing biomass, the Korea, which produces too little biomass of its own, can meet the needs of the renewable energy sectors. In the case of import biomass, it will cost a great deal on the transportation and logistics of biomass materials. Therefore new research and development on the biomass fuel with high energy density is needed to reduce logistics cost on transportation of the biomass fuel. Torrefaction is a thermochemical treatment process of biomass at temperatures ranging between 200 and 300oC. Typically, 70% of the mass is retained as a char product, containing 90% of the initial energy content. Torrefaction experiments on samples of EFB were performed in a fixed bed reactor to determine the effect of operation variables such as reaction temperature (205-310oC), reaction time (20-40 min) and air ratio (0-0.18) on char yield and characteristics. Increase of the torrefaction temperature led to a decrease of the yield of the char. The heating value of char increased with the increase of the reaction temperature, because the carbon content increased and hydrogen and oxygen content decreased. The yield of char decreased with increasing air ratio. This suggested that oxidation of EFB occurred during torrefaction in the presence of oxygen.

Key Words

Torrefaction, Empty fruit bunch, Palm oil, Carbonization, Biomass

김정호 Jeong Ho Kim , 남세용 Se Yong Nam

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Abstract

This study aimed to investigate the influence of the conditioning properties such as pH, mixing speed and reaction time on the dewaterability of sewage sludge and compare the performance with the derived conditions at the different solid concentrations. Performance parameters including time to filter test (TTF), specific resistance to filtration (SRF) and water content showed the optimum result at the pH value of 3, the rapid mixing speed of 200 rpm, and the slow reaction time of 20 min. In case of 20,000 mg/L of TS, a dosage of 1.0 g inorganic conditioner/L-sludge decreased TTF, SRF, water content of dewatered sludge cake, turbidity of the supernatant from 146 to 22 sec, 2.0 × 1014 to 0.4 × 1014 m/kg, 81.6 to 74.8% and 112 to 51 NTU, respectively.

Key Words

Conditioning properties, Sludge dewatering, Inorganic conditioner

김정대 Joung Dae Kim , 박준석 Joon Seok Park

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Abstract

This research was performed to evaluate the physicochemical characteristics of waste oil, waste solvent, and waste paint as waste derived fuel (WDF) feeding materials and WDF. Low heating values (LHVs) were in the ranges of 8,313.8 ~ 10,989.5 kcal/kg for waste oil, 4,109.1 ~ 9,890.6 kcal/kg for waste solvent, 5,733.7 ~ 8,051.0 kcal/kg for waste paint, and 5,184.2 ~ 10,679.0 kcal/kg for WDF. Sulfur contents showed 0.010 ~ 1.900% for waste oil, 0.000 ~ 0.073% for waste solvent, 0.004 ~ 0.581% for waste paint, and 0.001 ~ 0.700%, respectively. Chloride contents showed the ranges of 2 ~ 4,870 mg/kg for waste oil, 0 ~ 12,900 mg/kg for waste solvent, 0 ~ 10,700 mg/kg for waste paint, and ``not detected`` ~ 4,070 mg/kg for WDF. Cd, As, and Hg were detected minimally in a few sample only. Other heavy metals showed below standard permission value for WDF. Feeding materials for WDF showed greatly different characteristics within even same sorts of wastes. And, as results of LHV, S, Cl, and heavy metal contents, WDF samples investigated in this research satisfied the standard permission value for WDF.

Key Words

Waste oil, Waste solvent, Waste paint, Waste derived fuel (WDF), Recycling

이남훈 Nam Hoon Lee , 남상철 Sang Chul Nam , 강정희 Jeong Hee Kang , 남궁완 Wan Nam Koong , 허광범 Kwang Beom Hur

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Abstract

Interest in the measurement of siloxane which reduces energy efficiency of biogas, has increased with its market extend. Even though the impinger absorption method takes long sampling time of 2-3 hours and need a complicated equipment, it has been typically used for the sampling method of siloxane. This study was conducted to apply the gas bag sampling method with tedlar bag and aluminium bag for improving the method of siloxane sampling. To compare efficiencies of siloxane sampling, the manufactured gas, landfill gas, and digestion gas were used as sample gases. According to the result, materials of gas bags did not cause measurement error and there was no loss of siloxane by adsorption on the inner surface of gas bag. The result of D4 calibration in the tedlar bag, showed higher than 0.99 in the coefficient of determination. In case of digestion gas, the analysis results of two samples collected by the tedlar bag and the impinger absorption were almost same. The differences of analysis result between landfill gas and digestion gas were considered due to the short sampling time and the absence of gas storage tank.

Key Words

Biogas, Siloxanes, Sampling method, Impinger absorption, Gas bag sampling