민병연 Byeong Yeon Min

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Abstract

This Paper describes the domestic and international status for melt decontamination, which has been knows as the most effective technology for the volume reduction and recycling of the metal wastes generated from nuclear facilities. The recycle or self disposal of metallic wastes can be considered as one of the waste management options under the circumstances of the capacity limitation of a waste disposal in Korea. The limited recycle or self disposal of the metal wastes through an melt decontamination have the merit from the positive view point of the increase in resource recyclability as well as the decrease in the amount of wastes to be disposed resulting the reduction of disposal cost and the enhancement of disposal safety. Among the scenarios for recycle and reuse of the radioactive metallic wastes, the most feasible and reasonable one is limited reuse option, in which the ingot can be recycled as the products such as the waste drums and ISO containers. Prior to recycle and reuse in the nuclear sector, however, the regulatory criteria for the recycle and reuse of metallic wastes should be established in parallel with the development of the recycling technology.

Key Words

Melt decontamination, Decommissioning, Radioactive metal waste, Self disposal

김삼권 Sam Cwan Kim , 김경섭 Kyung Seop Kim , 함상이 Sang Yee Ham , 허종원 Jong Won Heo , 이정섭 Jung Sub Lee , 석광설 Kwang Seol Seok , 이지윤 Jee Yoon Lee , 고윤화 Yun Hwa Ko

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Abstract

The dechlorination processes and efficiencies of PCBs contained in transformer dielectric oils were investigated on three commercial-treatment companies. Alkaline dispersion method was used for dechlorination of PCBs mainly using molten metallic sodium or potasium hydroxide with PEG, and its dechlorination efficiency to whole congeners of PCBs was 98.94% on average. Homologues of highly-chlorinated biphenyls showed better efficiencies than those of less chlorinated ones, especially mono-chlorinated biphenyl in para-position (#2) was about 37 times enriched after chemical treatment. Co-planar PCBs` dechlorination efficiency was averaged as high as 99.78%, but 3,3``,4,4``-TeCB was relatively low as 96.5%. It was suggested for better dechlorination efficiency to remove the water in transformer oil prior to chemical reaction and to stir the reagents more rapidly when using alkaline dispersion method.

Key Words

PCBs, Transformer Oil, Dechlorination, Alkaline Dispersion

박진규 Jin Kyu Park , 김인회 In Hee Kim , 안영미 Young Mi Ahn , □口壯太郞 Sotaro Higuchi , 이남훈 Nam Hoon Lee

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Abstract

In this study, anaerobic co-digestion experiments for mixtures consisting of sewage sludge with food wastewater and livestock wastewater were conducted to assess the methane yields, the volatile solids (VS) removal rates and the dynamic kinetics. An augmented simplex centroid design (ASCD) was employed to design the mixing rate of organic wastes for the anaerobic co-digestion. Also, synergistic effects on the anaerobic co-digestion were studied using models obtained by the ASCD. As a result, synergistic effects were not observed in terms of methane yield and VS removal rate. It was just showed that there was a linear relationship between the cumulative methane yield and the mixing rate of food wastewater. The results might be attributable that the sewage sludge and the livestock wastewater had very lower C/N ratio compared with food wastewater that had a C/N ratio within a range required for a correctly operating anaerobic co-digestion. Therefore, increasing mixing rates of food wastewater increased the methane yield and VS removal rate, but there was not a synergistic effect by the anaerobic co-digestion.

Key Words

Sewage sludge, Food wastewater, Livestock wastewater, Anaerobic co-digestion, Augmented simplex centroid design, Dynamic kinetics, Synergistic effect

이승희 Seung Whee Rhee , 류돈식 Don Sik Ryu , 천승규 Seung Kyu Chun

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Abstract

Landfill gas (LFG) has received considerable attention to produce a renewable energy source from waste because LFG contains about 45 ~ 55% methane. In order to improve LFG, the concept of bioreactor landfill is applied to Sudokown Landfill site. In landfill field test, the research area 3A (300 m × 300 m) and reference area 2A (300 m × 300) are prepared to compare the effect of leachate recirculation. Using injection wells, leachate is injected into the research area in the 2nd Landfill site and the distribution of moisture content in the research area is homogeneously saturated by the injected leachate. Leachate characteristics such as Alkalinity, BOD, COD, TKN, and TOC are increased with the input of the injected leachate because wastes are decomposed by the injected leachate but pH of leachate is almost not affected by the injected leachate. The production of LFG in the reseach area is improved by about 40% comparing with that in the reference area and the content of CH4 in LFG is consistently higher than 50%. Hence, it can be summarized that the production and the quality of LFG can be improved by the injection of leachate into landfill site.

Key Words

Bioreactor Landfill, Leachate characteristics, Injection, Landfill gas, Resistivity survey

정성경 Seong Kyeong Jeong , 김우일 Woo Il Kim , 신선경 Sun Kyeong Shin , 강영열 Young Yeul Kang , 연진모 Jin Mo Yeon , 김민선 Min Sun Kim , 조윤아 Yoon A Cho , 김나 Na Kim , 오길종 Gil Jong Oh

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Abstract

Waste dusts generated from various metallurgical processes were investigated for effective management of the designated waste in South Korea. Source of the study were selected based on the industries registered on the Allbarosystem. Raw material, products and manufacturing process were investigated on-site and leaching behavior of six heavy metals (Cr6+, Cd, Cu, Pb, Hg, As) along with CN was studied in 41 waste dust samples. We identified 14 samples exceeded the Korean regulation standard out of which 5 samples were designated waste. We suggest that regular monitoring is essential for the proper management.

Key Words

Metallurgy, Waste dust, Leaching, Designated waste

김승도 Seung Do Kim , 김의건 Eui Kun Kim , 김혜림 Hye Rim Kim , 이영표 Young Phyo Lee , 박준호 , 변석호 Seok Ho Byun , 서형주 Hyoung Ju Seo , 이소향 So Hyang Lee

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Abstract

This paper attempted to estimate the emissions of HFC-134a from scrap passenger vehicles as a result of measuring the residual quantities of HFC-134a in scrap vehicles. We measured the residual amounts in the scrap passenger vehicles of 196 by applying commercial recover for refrigerants. The average residual rate is reported to be 61.2 ± 2.4% with a confidence interval of 95%. As expected, the higher residual rates are shown for recent models. Little variation, however, is made with vehicle size. The HFC-134a emission quantity from scrap passenger vehicles in 2011 is estimated to be 326,236.83 tCO2 eq that demonstrates 53% increase to compare with that in 2007. As the numbers of passenger vehicles have increased dramatically during the last two decades, the emissions of HFC-134a from scrap passenger vehicles would increase sharply in the next coming years. The chemical compositions of refrigerants from scrap passenger vehicles are quite similar to those of new refrigerants, suggesting that the refrigerants from scrap passenger vehicles could be reused.

Key Words

Greenhouse gas, HFC-134a, Refrigerant, Emission factor, Residual rate, Scrap vehicles

권상우 Sang Woo Kwon , 최병운 Byeong Woon Choi , 박우민 Woo Min Park , 전관수 Kwan Soo Jun

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Abstract

Electrochemical reductive extraction of copper from LCD manufacturing process and through hole plating process for PCB circuit board wastewater was experimented using synthetic wastewater. Copper plate which could be used as raw material through melting with extracted copper from wastewater and graphite plate were used as a cathode and an anode, respectively. The copper extraction could be optimized in pH 2 and polar space of 45mm. The extraction rate of copper per unit energy was decreased as HRT increased and initial copper concentration decreased. As the optimal HRTs which could maximize the productivity for copper on energy, 80 ~ 110 min at 50 mg/L, 64 min at 1,000 mg/L and 77 ~ 98 min at 3,000 mg/L were determined, respectively.

Key Words

Copper, Electrochemical extraction, Wastewater treatment, Polar space, Electroplating, Urban mining

남상철 Sang Chul Nam , 김인회 In He Kim , 남궁완 Koon Wan Nam , 이남훈 Nam Hoon Lee

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Abstract

This study was conducted to improve the analytical method of siloxanes in biogas. Methanol and hexane were tested as absorption solvents of the impinger absorption method, and also the hexane extraction for pretreatment of sample was evaluated. Manufactured gas contained siloxanes of 50 ppm was completely absorbed by the methanol impinger absorption. The absorption efficiency of biogas containing only 2 ppm, however, was maximum 84%. As the condensate on the first impinger increased, the absorption rate of methanol was decreased. The hexane extraction method of the sample was considered to proper the method of moisture removal. The hexane extraction result showed the high recovery factor and the low relative standard deviation. It is suggested that the suitable choice of solvent and pretreatment is required, as the analysis result of siloxane sample may be differentiated depending on the type of biogas or the sampling point.

Key Words

Biogas, Siloxanes sampling, Impinger absorption, Humidity, Hexane extraction

형원길 Won Gil Hyung , 안양진 Yang Jin An , 문경주 Kyoung Joo Mun , 윤성진 Seong Jin Yoon

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Abstract

This study aims to develop solidifying agents of sewage sludge using industrial By-Products and evaluate applicability of the solidified sewage sludge. The result of this study shows that it was possible to reduce water content of the cover materials to more than 50% in a short time as a result of the excellent hygroscopic function of inorganic binder made from industrial by-products and the granulation of sludge. The result suggests that the appropriate mixed ratio of (PSA + CPA) - (GBFS + SM1) - (SAS + SM2) is 60-25-15, and input ratio of solidifying agent is 48%, considering the applicability of the facilities, including mixing performance and availability of discharge, as well as the percentage of moisture content of the solidified sewage sludge, pH, and exothermic temperature. The solidified sewage sludge made using industrial by-products met more than the standard of unconfined compressive strength 0.5 kg/cm2 (as for cover materials 0.1 MPa) in 7 days due to ground granulated blast furnace slag, high-calcium fly ash, and SAS. As a result valid resource recovery is possible through the land treatment of sewage sludge by inducing in-situ stabilization of heavy metals and property strengths through the reactivity of industrial by-products.

Key Words

Industrial by-products, Solidifying agent, Artificial soil, Cover materials, Solidified sewage sludge

윤수경 Sue Kyoung Yun , 이원근 Won Keun Lee , 원종철 Jong Chul Won , 천승규 Seung Kyu Chun

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Abstract

SLC has installed and operated a 50 tons/day scale pilot plant of construction & demolition waste (c&d waste) separation/selection pilot plant in order to utilize wood wastes among construction wastes carried into landfill sites as energy sources, etc. In the present study, for optimized operation of the aforementioned pilot plant, the characteristics of operation of the plant were assessed in relation to changes in operation conditions and the characteristics of inputted wastes. Based on the results of an experiment conducted to select sieves of vibrating screens for the discharge of incombustible materials, wood waste recovery rates were the highest when 8mm sieves were applied but the purity of wood wastes and combustible materials was higher when 20 mm sieves were applied. By supplementing the shape of the overflower of the wet separator, combustible materials stagnant in the water tank were reduced and the rate of recovery of combustible materials including wood was improved by around 10%. It was identified that not only the amounts of wood wastes and combustible materials among inputted wastes but also the ratio of coarse combustible materials to entire combustible materials could affect operation time. Therefore, if processes to select or smash coarse combustible materials in advance are added and bottle neck points are supplemented to be prepared for an increases in the amount of inputted combustible materials, construction wood waste selection/separation facilities could be stably operated even when the characteristics of inputted wastes are changed.

Key Words

Construction & Demolition waste, Separation, Wood waste, Vibrating screen