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        검색결과 11

        1.
        2018.01 KCI 등재 서비스 종료(열람 제한)
        In this study, the efficiency of the anaerobic co-digestion of three categories of rural organic waste (animal manure, slaughterhouse waste, and agricultural by-products) and different mixtures of them was investigated. In addition, the relationship between digestion efficiency and the carbon/nitrogen (C/N) ratio was also conducted. Five different mixtures of feedstock including animal manure as a control were estimated by the biochemical methane potential (BMP) test. The results indicate that the biodegradability of the feedstock mixtures was in the range of 62 ~ 75%, which was at least 1.4 times higher than that of single digestion (43%), while the methane yield was increased by almost twice that of single digestion (0.14 to 0.24 ~ 0.41 m3 CH4/kg VSadd). After the BMP test, four feedstock mixtures were selected for a lab-scale reactor, including animal manure as a control sample. The highest methane yield of 0.355 m3 CH4/kg VSadd was obtained from the A4-mixture sample. With regard to the C/N ratio, the mixture materials showed an increase in methane yield by at least 1.2 times (13.4 to 16.4 ~ 21.3%), which means that the C/N ratio had an effect on the performance of co-anaerobic digestion.
        2.
        2016.06 KCI 등재 서비스 종료(열람 제한)
        Solid-liquid separation is important for securing safe runoff quality in the biological treatment process. In particular, the method for determining sludge settlement characteristics using SVI, which is a parameter, evaluates the precipitation features of sludge in an aeration tank and secondary precipitation tank and is a simple and widely used method. However, in methods using SVI, the accumulation of objective data is usually not possible, since the subjective judgment of operators is mainly involved in this evaluation method. Therefore, the automation of SVI measurement is required to improve the determination method of sludge settlement using SVI. In this study, an automatic measurement system of SVI using optics was developed. To evaluate the reliability of the measurement system, a visual inspection test was performed in parallel with our suggested SV30 auto-measurement system using actual sludge and a similar tendency in the results was obtained. Using this suggested SV30 automation system, the indirect determination of MLSS (Mixed-Liquor-Suspended-Solids) activation states of the aeration tank and precipitation tank is also expected to be possible. Through the test results, it was verified that the reliability of SVI determination was increased by identifying the effect of outside light after performing a test under external light interference.
        3.
        2015.05 서비스 종료(열람 제한)
        Hydrometallurgical process, which is one of the recycling method of EAFD in zinc, is a process to recover metallic crystal form that deposited on the cathod through electrolytic extraction by leaching valuable metals in appropriate solvent. Still, there is a lot of variable at electrowinning process, such as initial pH, space between electrode, voltage, current, cathod, or anode, Thus, many studies have been conducted previously. In this study, the consideration of optimistic condition in electrowinning process to recover the valuable metal in EAFD have been carried. The extraction amount by changing pH shows increase according to high initial pH, also, the alteration of extraction amount by controling the space between electrode, voltage or current has been measured. The difference of efficiency represent by decrease of electromotive force, sudden loss of voltage under specific condition, and using platinum as electrode shows most stable extraction. Furthermore, when distance between electrode are too close, the extracted zinc contact with anode, which make recovery difficult. The analysis result of zinc metallic crystal which been recovered draws spherical and cylindrical shapes are scattered and mixed, and consequence of EDX, content of zinc appear about 60%.
        4.
        2015.05 서비스 종료(열람 제한)
        The purpose of this study was to evaluate the applicability of the microbial fuel cell for the combined treatment of food waste water and landfill leachate. Contents of the study was to develop a carbon-containing electrode material radially to maximize microbial attachment. Also to evaluate the electric energy production efficiency by combining the electrode surface coating technology. By using a microbial fuel cell organic matter and nitrogen removal efficiency is evaluated for the food waste water and landfill leachate. BET to evaluate the surface characteristics of the developing electrode (Brunauer Emmett Teller) To evaluate the coating adhesion through measurement and to evaluate the adhesion characteristics micro-organism Weighing. Excellent electrical conductivity in the development electrode platinum, cobalt, by coating a catalyst such as palladium and to evaluate the electric energy generation efficiency. Lab. scale reactor capacity is a 5 L, and to configure the cross-section and the oxidizing electrode as cathode sequentially added.
        5.
        2015.05 서비스 종료(열람 제한)
        Livestock Wastewater shall cause a high concentration of organic matter and nutrients such as rivers because of the lake and groundwater contamination, such as the accumulation of nutrients in the soil contained in the manure, livestock wastewater containing large amounts of organic matter that will flow to the river or appeal If eutrophication, and comfortable living environment to cause harm, such as odor and pest damage and can. Organic waste and organic waste, such as the world has a direct interest in acquiring the available resources and the development of clean energy from waste is a growing desire, is expected to contribute to the environment from waste materials industry growth by developing innovative technologies such as direct electrical energy production. In the case of livestock waste water and high concentration of organic material in addition to containing ammonia nitrogen, nitrate nitrogen for nitrification is created due to the electron acceptor is used as the fuel cell according to this has been reported to decrease the efficiency of electricity production. Therefore, to derive the electricity production efficiency due to organic concentration and ammonia nitrogen concentration in order to apply a microbial fuel cell (MFC) livestock wastewater treatment process in this study, and to derive the energy production potential with livestock waste water through the study. Lab. scale Reactor fabrication and operation to try to derive the reaction factor of the optimum operating conditions in accordance with the livestock wastewater applied through the evaluation of trends and removal efficiency of organic matter and nutrients in the microbial fuel cell. In addition, from the final research results, I try to present the direction of future research for the improvement of application possibilities and microbial fuel cell power generation efficiency of microbial fuel cell in the livestock wastewater treatment facilities.
        6.
        2007.12 KCI 등재 서비스 종료(열람 제한)
        Heavy metal concentrations in the soil were investigated for the abandoned Samkwang metal mine, Cheongyang-Gun, Chungnam Province, Korea. The concentrations of heavy metal(As, Cd, Cu, Ni, Pb, Zn) were determined in mine soils collected at the abandoned mine sites to obtain a general classification and specification of the pollution in this highly polluted region. The results estimated with the normal test and basis statistic on the central tendency and variation showed that the distribution of heavy metal concentration had significantly different at the range of all locations. The range of spatial distribution on the relationship of heavy metal concentration and pH was 4.8∼8.8 and heavy metal concentration on the type of land use was highest in forest land, and also Ni and Zn in farm and rice field showed the high concentration. The distribution of heavy metal concentration on the depth of a soil showed that the metal concentrations in subsoil were higher than of those in surface soil, while the concentration of Cu and Ni had no significant difference on the depth of soil. Results from the correlation analysis using the data except the extreme and unusual data revel that Zn-Cd(r=0.867), Zn-As(r=0.797), Zn-Pb (r=0.764), Cu-Cd(r=0.673), Cu-As(r=0.614) and Zn-Ni(r=0.605) were the most important parameters in assessing variations of heavy metal in soil. To discriminate pattern differences and similarities among samples, principal factor analysis(PFA) and cluster analysis(CF) were performed using a correlation matrix. This study suggests that PFA and CF techniques are useful tools for identification of important heavy metal and parameters. This study presents the necessity and usefulness of multivariate statistical assessment of complex databases in order to get better information about the quality of soil and gives the basis information to clean up the abandoned mine sites.
        7.
        2007.10 KCI 등재 서비스 종료(열람 제한)
        This paper represents the statistical characteristics of sources and receptors for road traffic noise in apartment complex. Also we suggested that the site-specific characteristics of vertical and horizontal distributions in the complex apartment have been derived using a different analysis for evaluating levels of Leq1h by the apartment floor at a given distance from a road in terms of the flow rate, the mean speed of the traffic, and the percentage of the type vehicles in the day and night periods. As a result, the contribution orders of traffic quantity by the type of vehicles showed as followed: light vehicle>medium vehicle>heavy vehicle>motorcycle. Especially, the mixing ratio of entering the road on the heavy vehicle in the daytime was two times higher than that of in the night. The speed in all types of vehicle is in the range of 41 and 81 km/hr and noise level was not significantly different in day and night-time. The sources of road traffic noise had different variations and uncertainties using a random variable and probability distribution. The sound distribution to receptors by the apartment floor showed S curve between 1st floor and 15th floor With the normality test, the normal distributions using Anderson-Darling Test followed 1st, 3th, 13th and 15th floor in the daytime and all floors except 7th floor in the night (p>0.05). And also, the value of the pearson correlation coefficient (r) obtained in this study have significantly different at the range of floor. In conclusion, the results suggested that the distribution characteristics of levels of Leq1h on the sources and receptors of road traffic noise in apartment complex must be improved and developed on the guideline of regulation of road traffic noise.