김정훈 Jeong Hoon Kim , 강호철 Ho Cheol Kang , 김영운 Young Wun Kim , 이은수 Eun Soo Lee , 임귀택 Gui Taek Lim , 방경모 Kyung Mo Bang , 빈혜선 Hye Seon Been

DOI:

Abstract

A study on the recovery of lanthanum and cerium has been investigated by using fatty acids with various carbon chain lengths - octanoic acid, 2-ethylhexanoic acid, neo-decanoic acid, dodecanoic acid, tetradecanoic acid and oleic acid. In order to improve the selectivity of lanthanum and cerium, the effects of the following factors on recovery experiment have been considered: i) fatty acids with various alkyl chain lengths, ii) the concentration of extractant, and iii) pH. The results show that the extraction efficiency of lanthanum was higher than that of cerium at the same pH condition and pH0.5 is increased with increasing the length of the carbon chain of the extractant. As results of the tests using various fatty acids as an extractant, the selectivity of lanthanum and cerium is highest when tetradecanoic acid was used as a extractant. The extraction mechanism of lanthanum and cerium was varied with the change of concentration of the tetradecanoic acid. MR3 single-species was formed from the lanthanum and cerium ion in the extractant concentration less than 0.1 M. On the other hand, the lanthanum or cerium ion is solvated with three molecules of tetradecanoic acid monomer like MR3·3RH in the extractant concentration more than 0.1 M.

Key Words

Selectivity, Recovery, Lanthanum, Cerium, Fatty acid, Extraction

김수진 Su Jin Kim , 배재근 Chae Gun Phae , 김제남 Jae Nam Kim

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Abstract

This research has looked into the transport process of plastic waste generated from domestic and industrial waste within the region and in order to modify the problem that may occurred during the mass balance were analyzed for development of suitable solid waste recycling network regionally. As result, quite amount of plastic is being transferred to another region, even though a treatment facility`s capacity could bear the total amount of waste generated within the area. Although plastic waste could be treated locally, it is analyzed that amount of waste are being transferred due to inefficient and irrational processing system between regions. It is assumed that CO2 generated and loss of unnecessary fuel cost from these inefficient system is quite a lot and in order to modify this disorganized system, the plastic waste should be treated based on the characteristics of each regions. Also, the waste recycling system should be studied with the efficient, environmental friendly processing and delivering network by minimized transfer distance and local systemizing the waste treatment system.

Key Words

Plastic waste, Solid waste recycling network, Mass balance, Delivering network

강성원 Sung Won Kang , 이태윤 Tae Yoon Lee

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Abstract

Filtration tests were conducted using wood waste chips to determine the feasibility of using these chips as a filter media for soil efflux. Main experimental parameters were height of filter media and linear velocity of inflow water. Removal efficiency of turbidity and TSS were increased as the height of filter media increased. At the height of 150 cm of filter media, removal rates of turbidity and TSS were 46-54% and 72-80%, respectively. In addition, d50 of effluent decreased as the height of filter media increased, but d50 was not affected by linear velocity of influent. Effluent TOC measured at the test with the filter height of 100 cm and linear velocity of 10 mm/hr was 3.52 mg/L, which was a 70% reduced value of influent TOC. From this study, we can expect the feasibility of wood waste as a filter media to remove soil particles in water.

Key Words

Wood waste, Construction sites, TSS, Turbidity, TOC, Soil particles

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

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Abstract

The material flow was analyzed to estimate the amount of organic sewage sludge at each process of waste treatment. The greenhouse gas emission from waste treatment process of organic sewage sludge was estimated and the reduction potential of greenhouse gas emission was predicted. Four different scenarios were designed to evaluate reduction potential of greenhouse gas, assuming that the amount of ocean disposal of organic sewage sludge could be transferred to energy process such as LFG recovery (scenario 1), production of biogas through anaerobic digestion (scenario 2) and sludgederived-fuel (scenario 3). Scenario 4 was based on the policy of the Ministry of Environment about waste treatment facilities. The results from material flow analysis showed that 53.9% of sewage sludge was treated by ocean disposal, 22.5% by recycling, 18.8% by incineration, and 4.8% by landfill. The amounts of greenhouse gas emissions were estimated to be 53,849 CO2-ton/yr for incineration, 22,804 CO2-ton/yr for recycling, and 9,828 CO2-ton/yr for landfill. The scenario analysis showed that reduction potential of greenhouse gas was estimated to be 10,907 CO2-ton/yr by scenario 1, 77,544 CO2-ton/yr by scenario 2, 31,867 CO2-ton/yr by scenario 3, and 10,049 CO2-ton/yr or 73,507 CO2-ton/yr by scenario 4.

Key Words

Sewage sludge, Waste treatment, Material flow analysis, Greenhouse gas emission, Scenario analysis

박상원 Sang Won Park , 이갑두 Kamp Du Lee

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Abstract

In this study, efforts were made to immobilize TiO2 powder by using the cast-iron sand as a support material. Surface characteristics of ceramic mixed photo-catalyst were analyzed by FE-SEM. The immobilized ceramic mixed photo-catalyst was tested to investigate its capacity to reduce color in wastewater. Dye materials used in this study were Suncion Yellow H-E4RN as the reactive dye and methylene blue as the direct dye. 73% of the direct dye and 65% of the reactive dye were removed at the given conditions. In order to increase its photo-activity, α-Fe2O3 was added to ceramic mixed photocatalyst. Ceramic mixed photo-catalyst showed better color removal efficiency up to 10% than pure TiO2.

Key Words

Ceramic, Decolorization, Mixed photo-catalyst, Suncion yellow H-E4RN, TiO2

박상원 Sang Won Park , 이갑두 Kamp Du Lee

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Abstract

In this study, Making of ferrioxalate photocatalyst carring activity in the range of visible ray was investigated by removal of chlorophenol and nitrobenzene. Photoactivity of ferrioxalate photocatalyst was estimated results of experiment in several condition. Ferrioxalate photocatalyst was the most effective at pH 5 in removal of chlorophenol and nitrobenzene. The optimum injected amount of ferrioxalate photocatalyst is 0.5 g/L. Through experiments of different light source, ferrioxalate photocatalyst was confirmed to photoactivity in the range of visible ray. Under the chosen condition, removal rate of chlorophenol showed 95% in UV, 60% in fluorescent light and removal rate of nitrobenzene showed 60% in UV, 30% in fluorescent light. Also, we can predict destruction of aromatic compound by analysis TOC and material variation of biodegradation through it.

Key Words

Aromatic compound, Chlorophenol, Ferrioxalate, Nitrobenzene, Photocatalyst

김경 Kyung Kim , 김형욱 Hyung Wook Kim , 이남훈 Nam Hoon Lee , 윤석표 Seok Pyo Yoon , 이병선 Byung Sun Lee

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Abstract

We studied the effect of different air flow rate on the quality and quantity of aerobic landfill lysimeter leachate. For 3 months, 0 ~ 5 pore volume/day air were injected to lab-scale lysimeter, and leachate quality and quantity were measured once a week. From results, 5 pore volume/day of air injection rate were recommended to stabilize municipal solid waste landfill for mid-term aerobic operation of waste stabilization. Times to reach 95% reduction rate of COD concentration of leachate were 4 weeks and 10 weeks after air injection for 1 pore volume/day and 5 pore volume/day respectively. Moisture contents of landfilled waste were increased with air injection rate, and this increase might make favorable environment for biodegradation of landfilled organic waste.

Key Words

Lysimeter, Aerobic Landfill, Air flow-rate, Leachate, Moisture content

김형민 Hyung Min Kim , 이승희 Seung Whee Rhee , 박헌수 Hun Su Park

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Abstract

Numerical simulation was carried out to decide the optimal conditions of air flow rate and inlet angle for collecting phosphors from tube of spent fluorescent lamp. The grid of the tube is composed by 3-dimensional system with tetra shape to secure the degree of precise of numerical solution. In the simulation, the scale of tube is 1,000mm in length and 32mm in diameter. The inlet angle of air flow in the tube is classified by 5 cases such as 15°, 30°, 45°, 60° and vertical (90°) to cross sectional area of the tube and the air flow rate is increased from 700 cm3/min to 5,800 cm3/min. From the results of the numerical simulation, the shear stress at the surface of tube is almost constant with increasing air flow rate when the inlet angle of air flow is vertical (90°) to cross sectional area of the tube. When the inlet angle of air flow is less than 60°, as distinct from the inlet angle of 90°, the shear stress at the surface of tube is increased with increasing air flow rate. When the mean shear stress of the tube is about 0.5 N/m2, in which it can collect phosphor readily without any back pressure in the tube, air flow rate is measured by 2.8 L/s. Hence, the optimal condition of air flow rate and inlet angle in the tube of spent fluorescent lamp can be decided by 2.8 L/min and 60°, respectively.

Key Words

Spent fluorescent Lamp, Phosphor, Numerical simulation, Flow rate, Separation

김석환 Seok Hwan Kim , 이수구 Soo Koo Lee , Cheng Kai Chai

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Abstract

This study was performed to find the effect of moisture content on the stabilization of heavy metals in fly ash discharged from municipal solid waste incinerator. The fly ash was classified as designated, hazardous material in which especially leaching concentration of lead was high over 35 mg/L. The aging, natural weathering process based on carbonation technology was applied to stabilize heavy metals in fly ash. The moisture content in fly ash could be easily changeable and hard to maintain constant level due to water vaporization and surface drying effect on ash particles. This can cause data fluctuation and reduce the reliability of experimental results in the evaluation of heavy metal stabilization process. In this study, the moisture content and CO2 concentration was maintained at constant level by semi-closed system applied to prevent water vaporization. The experimental results showed that moisture content was the important parameter and the leaching concentration of heavy metals was sharply decreased with moisture content in the range of up to 30%. Lead and copper concentrations could be quite rapidly decreased with aging time and even lead concentration showed below regulatory level within 15 days in the weathering condition without chemicals. pH of fly ash was well decreased with time in the range of 20 ~ 30% moisture content and related with the stabilization of heavy metals. The optimum moisture content was considered 20% in viewpoint of stabilization and actual operation. The results of sequential extraction procedure showed that exchangeable and carbonate fraction of lead and copper was reduced and residual fraction was increased with moisture content and mobility factor.

Key Words

Moisture content, Fly ash, Heavy metal, Lead, Copper, Aging

김상국 Sang Guk Kim , 이종철 Jong Chol Lee , 박수진 Su Jin Park , 현주수 Joo Soo Hyun

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Abstract

Solid propellant for the rocket motors contains large amount of ammonium perchlorate (AP) as an oxidizer. To recover AP from unserviceable or waste rocket propellants, water-washout of AP from the propellant was proven to be safe and environmental-benign process. However this process produces high concentration of AP solution by using water jet. Since AP was known to cause the thyroid gland disorder, it should completely recycled or destructed in a closed system. One of the treatment method for the AP solution is incineration. In this research, we used submerged quench incineration system to destroy the AP solution generated from the water-washout process. When the AP solution is sprayed into the incinerator, NOx and HCl were produced as main gases. A De-Nox system comprising by wet oxidation and reduction units were used to remove NOx gases. When the 19.6wt% AP solution was injected to the incinerator at a feed rate of 9.4 kg/hr, NOx concentration measured at the exit of the incinerator and reduction tower was 974ppm and 48ppm, respectively with O2 12% correction showing NOx reduction rate as 95.1%. Hydrogen chloride resulted from AP decomposition was absorbed to the circulation water in the quencher. The quench water becomes acidic rapidly with incineration time. Perchlorates measured from the flue gas at stack was zero which indicates that no perchlorates were discharged to the atmosphere.

Key Words

Ammonium perchlorate, Submerged-quench incinerator, Solid rocket propellant demilitarization, De-NOx System

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

DOI:

Abstract

The production process of waste oil based biodiesel was introduced in experimental manner. Ultrasonic energy was irradiated to induce the trans-esterification of the waste oil. The ultrasonic irradiation had two effects, those were heating and mixing of the reactants. We performed the experiment under various production parameters, viz., the ultrasonic irradiation time, sonic power, methanol/waste oil mole ratio, and reaction temperature. The optimum condition was determined at an ultrasonic irradiation time = 30 min, sonic power = 500 W, methanol/waste oil mole ratio = 7 when the reaction temperature was 55oC. We suggest that new biodiesel production processes using ultrasonic energy would alter the conventional process of heating and mixing.

Key Words

Ultrasonic energy, Biodiesel, Waste oil, FAME content, Biodiesel yield

윤오섭 Oh Sub Yoon , 이원준 Weon Joon Lee

DOI:

Abstract

WtE (Waste to Energy) become very popular in Korea, and RDF (Refuse Derived Fuel) of MSW(Municipal Solid Waste) was one of the waste treatment measures besides recycling, landfill and incineration. The process employed to the first facility(W-RDF Plant) of RDF utilized the shredded and dried MSW just separating the non-combustibles; that is, biodegradable portion of the MSW was included in preparing the RDF. The other RDF plant(S-RDF Plant), however, separated the biodegradable portion of the MSW before drying to prevent the biodegradable waste from including the RDF production and save the energy for drying the whole MSW. Consequently, the RDFs produced from these two different process has an distinguished characteristics in their fuel properties, as well as the incineration characteristics. It can also be expected that the air pollution emissions are different from each other. In this study, two types of the RDFs were investigated using TGA(Thermogravimetric Analysis) which was specially designed for incinerating relatively large amount of samples. During TGA test, the CO, NOx, SOx and HCl in the combustion gas were measured to understand the air pollution generation pattern. It can be concluded that the RDFs produced without biodegradable portion of MSW had a higher calorific value and coal like combustion pattern. The chorine contents in this RDF without biodegradable portion was lower than the RDF with biodegradable portion of MSW, but the HCl concentrations in the flue gas was not varied as much as the chlorine contents of two types of RDF. Whereas, the SOx concentrations in the flue gas was different as much as the sulfur contents in the two different types of RDF.

Key Words

RDF, Fuel property, TGA, Combustion Characteristics, Flue gas air pollutants

김동수 Dong Su Kim , 백미화 Mi Hwa Baek , 박수화 Soo Hwa Park , 이하연 Ha Yeon Lee

DOI:

Abstract

Separation of Nickel from the magnetic substance in the recycling process of spent lithium primary batteries has been investigated. Magnetic substance was separated by a magnet separator and the separation of nickel from the obtained magnetic substance was carried out employing several solvents. Nickel separation percentage was found to be increased with the stirring time, stirring speed and pulp density within the investigated experimental conditions. In general, acetone was examined to be most efficient in nickel separation and more than 60% of nickel was found to be separated in the pertinent conditions. Nickel separation percentage increased with reaction temperature and reached as high as 70% at 45oC. More acidic or basic water solution led to higher efficiency of nickel separation, which was examined to be above 80%.

Key Words

Lithium primary battery, Recycling, Physical separation, Nickel, Coagulation, Activated silica