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        검색결과 63

        41.
        2014.12 KCI 등재 서비스 종료(열람 제한)
        The large amount of waste oil sludge was generated from waste oil purification process, oil bunker, or the ocean plant. Although it has high calorific values, it should be treated as a designated waste. During the recycling process of construction and demolition wastes or the trimming process of woods, a lot of sawdust is produced. In this study, the feasibility of BOF (biomass and waste oil sludge fuel) as a renewable energy source was estimated. For manufacturing a BOF, a press type pelletizing was better than an extruder type and also 40 ~ 60% of mixing ratio in waste oil sludge was appropriate to produce a pellet. The pellet was 13 mm in diameter and 20 mm in length. There was no fixed carbon in waste oil sludge, and its carbon content and higher heating value were 63.90% and 9,110 kcal/kg, respectively. With an increse of mixing ratio of sawdust, the carbon content and heating value of the BOF were dropped, but fixed carbon content was increased. The heating value of BOF was in the range of 6,400 ~ 7,970 kcal/kg at the mixing ratio of 40 ~ 60% in waste oil sludge. It means that the BOF can be classified as the 1stgrade solid fuel. In TGA experiment carried out at heating rate of 10oC/min and under nitrogen atmosphere, thermal decomposition of sawdust was occurred in two steps, but waste oil sludge was destructed in one step. The initiated cracking temperature of sawdust and waste oil sludge was 300 and 280oC in respective and after 450oC the thermal decomposition process of sawdust was slowly progressed by 800oC in contrast to waste oil sludge. Thermal decomposition of waste oil sludge was finished around 600oC. It can be considered that this difference is due to the fixed carbon content. Thermal decomposition pattern for the pellet of mixing ratio over 50% in waste oil sludge was similar to that for waste oil sludge and thermal cracking was occurred between 300 and 350oC. As the mixing ratio of waste oil sludge in the pellet increased, the reaction of thermal cracking became fast.
        42.
        2014.10 KCI 등재 서비스 종료(열람 제한)
        In this study the effects of co-digestion of sewage sludge and food waste leachate on the anaerobic digestion efficiencyfrom sewage treatment facilities in S. Korea were investigated. For this study 15 facilities were selected including 9facilities treating sewage sludge only (S-Only) and 6 facilities treating sewage sludge and food waste leachate (S-MIX).The average volatile solid (VS) removal rate of S-Only was 30.7% and that of S-MIX was 45.2%. The COD removalrate of S-MIX (61.3%) was higher than that of S-Only (48.6%). It has been observed that the anaerobic digestion efficiencyof S-MIX was superior to that of S-Only because S-MIX contained more sufficient nutrient with higher VS contents andtotal solid (TS) contents emerging from food waste leachate. Therefore food waste leachate addition in sewage sludgeanaerobic digestion would be the preferred option to treat only sewage sludge.
        43.
        2014.10 KCI 등재 서비스 종료(열람 제한)
        The objectives of this research was to evaluate the anaerobic digestibility of waste activated sludge (herein after WAS)and waste beverages (herein after WB) in beverages manufacturing industry using actual plant under various conditions.In this study, anaerobic digestion with WAS and WB were evaluated according to different operating conditions. As thebasis operating conditions for anaerobic digestion, the reaction temperature was controlled at 35 and hydraulic retentiontime 30 days. WAS and WB were mixed at the ratio of 1:0, 9:1, 8:2, 7:3, 5:5, Respectively. The organic loadingrate (herein after OLR) was maintained less than 0.5kgVS/m3·day. Biogas productivity in accordance with VS was fedat the each mixing ratio with WAS and WB was increased from 0.92Nm3/kg VSfeed to 1.28Nm3/kg VSfeed, except mixingratio 5:5 (0.19Nm3/kg VSfeed). Also Biogas productivity in accordance with VS was removed at the each mixing ratiowith WAS and WB was increased from 1.13Nm3/kg VSrem to 1.81Nm3/kg VSrem, except mixing ratio 5:5 (0.35Nm3/kg VSrem). It was judged that pH was reduced with WB addition. From the results, it was judged that anaerobic digestionusing WAS and WB could be feasible.
        44.
        2014.10 KCI 등재 서비스 종료(열람 제한)
        The objective of this study was to find optimum pretreatment conditions of ozone and microwave for solubilizationof thickened waste activated sludge (TWAS). Response surface analysis was applied to determine the combination of ozoneconcentration (0.03 to 0.1g O3/g total solid (TS)) and microwave temperature (100~170oC). The temperature significantlyaffected the solubilization degree of sludge (p<0.01). Within the design boundaries, the conditions predicted to maximizethe solubilization degree of 41.6% were determined to be 0.065g O3/g TS and 170oC. On the other hand, the solubilizationdegree with the ozone pretreatment alone was 2.7 to 12.2% at 0.03~0.1g O3/g TS. The results show that the combinationof ozone and microwave pretreatments is effective in solubilization of TWAS.
        45.
        2014.09 KCI 등재 서비스 종료(열람 제한)
        The objectives of this research was to evaluate the anaerobic digestibility of waste actizvated sludge (WAS) and wastebeverages in beverages manufacturing industry using BMP test under various conditions. Also, the effects of physical(ultrasonic) and biological (lactobacillus) solubilization process on anaerobic digestibility of WAS were thoroughlystudied. The soluble chemical oxygen demand (SCODCr)/total chemical oxygen demand (TCODCr) ratio of WAS was 0.15but the SCODCr/TCODCr ratio after solubilization was increased 17.5% by ultrasonic, 18.8% by lactobacillus respectively.The results of BMP test, methane gas productivity as mixing ratio of WAS and waste beverages were 156ml CH4/gCODCr,164ml CH4/gCODCr and 182ml CH4/g CODCr, respectively 9:1, 8:2, 7:3 before the solubilization of WAS. As themixing ratio of waste beverages increase, VFAs concentration and methane productivity was increased. Also, methanegas productivity as mixing ratio after the solubilization of WAS using ultrasonic and lactobacillus was increased3.3~11.3%, 11.1~15.2% respectively. From the results, it was judged that anaerobic digestion using WAS and wastebeverages could be feasible.
        46.
        2014.04 KCI 등재 서비스 종료(열람 제한)
        This study provides a result of thermal mercury reduction for inventing a mercury recovery technology from the sludgewhich contains high concentration of mercury. Physical, chemical and thermal properties of the sludge were analyzed andmercury degradation at elevated temperatures was investigated to find out the optimum temperature range for thermalrecovery of mercury from the sludge generated from an industrial facility, which contained high concentration of mercury.The study was carried out in the temperature range of up to 650oC from 200oC, and 500~710µm particle size of wastesludge samples were selected from such industries. As primary thermal tests the sludge was heated up to observe weightdegradation at a continuous weight measurable thermogravimetric analyzer and a muffle furnace and the degradationcurves from both devices were found to be well matched. Mercury conversion to gaseous form was investigated fromthe analyzed data of mercury concentrations sampled every 25oC from a muffle furnace. Cold vapor atomic absorptionspectroscopy (CVAAS) Hg analyzer was used for the analysis of mercury content in solid and liquid samples. Most ofmercury was degraded and released as gas phase at the temperature range from 300oC to 550oC, which could be theoptimum temperature of mercury recovery by thermal method for the sludge containing high concentration of mercury.Based on these thermal mercury reduction studies, degradation kinetics study of mercury was conducted to provide thereaction kinetics data for further reactor design to recover mercury using a thermal method.
        47.
        2013.11 서비스 종료(열람 제한)
        In recent years, the demand of renewable energy fuels has been increased in worldwide because the capacity of fossil fuel would be not affordable in the near decade. As one of renewable energy fuels, the production of sewage sludge would be gradually increased by year, and it would be over than 10million tons in 2015 in Korea. Since ocean dumping was inhibited due to London Convention with being in effective at the end of 2012 in Korea, the combustion of sewage sludge has been emerged as one of alternative technologies of waste to energy. Meanwhile, it would be necessary to apply the carbon capture & storage (CCS) technology to reduce carbon dioxide originated from waste sludge incineration. During oxy-fuel combustion, a combination of oxygen typically of greater than 95% purity and recycled flue gas is used for combustion of the fuel. By recycling the flue gas, a gas consisting mainly of CO₂ and water is generated, ready for sequestration without stripping of the CO₂ from the flue gas. In this study, the pilot test was conducted by a circulating fluidized bed (CFB) combustor consisting of a riser, a cyclone, a down-comer, and a loop-seal. The CFB combustor has a riser with an inner diameter of 0.15m and a height of 6.4m. The experimental test was carried out with waste sludge in 30kwth CFB combustor operating with oxy-fuel and typical air conditions. The optimum temperature for waste sludge incineration was determined as 800℃. Oxygen with carbon dioxide as a combustion air was fed into a riser and a loop-seal in pilot test bed. The oxygen rate as a combustion air was ranged from 21% to 30% to observe the condition of waste sludge oxy-fuel combustion. The temperature and pressure profile in CFB reactor were depicted in the condition of typical air and oxy-fuel combustion. The flue-gas from typical air and oxy-fuel combustion was analyzed to observe the trend of carbon dioxide and air pollutants emission such as CO, NOx, and SOx, respectively. The production of carbon dioxide was approximately 90% in flue-gas from waste sludge incineration with oxy-fuel condition.
        48.
        2013.11 서비스 종료(열람 제한)
        Waste activated sludge (WAS) and food waste (FW) are available year round at low cost and have the potential to promote synergism in anaerobic digestion (AD). The goal of this study was to clarify the synergism in co-digestion of WAS and FW. A slight amount of FW at various ratios was added to WAS as an auxiliary substrate, and anaerobic batch tests were performed under mesophilic conditions. By adding FW, total CH₄ produced was increased, where most of them were come from WAS, clearly suggesting synergism. Also, lag period was shortened and CH₄ production rate was increased by FW addition. It was hypothesized that enhanced performance was owing to the facilitated hydrolysis of WAS by FW addition, which was revealed by the increased activities of hydrolytic α-amylase and protease.
        49.
        2013.04 서비스 종료(열람 제한)
        Domestic expressway are exposed to damage of combined deterioration by excessive use of deicer and a lot of cost is required for maintaining damage structures. Therefore, now is the time that durability of subsidiary concrete structures is required to enhanced in order to reduce maintenance cost of structures and to promote road safety. Thus, in this study measured compression strength and scaling resistance of concrete using the waste glass sludge
        50.
        2012.05 서비스 종료(열람 제한)
        The object of this research is to confirm the effect of Waste Glass Sludge on properties of concrete through compressive strength and Alkali-Silica reaction of concrete and to develop as construction material.
        56.
        2006.11 KCI 등재 서비스 종료(열람 제한)
        This study was performed to investigate the possible uses of waste sludge for the removal of heavy metal ions. The adsorption experiments were conducted with wastes such as sewage treatment sludge, water treatment sludge and oyster shell to evaluate their sorption characteristics. Heavy metals selected were cadmium, copper and lead. In the sorption experiments on the sewage treatment sludge, water treatment sludge, oyster shell and soil, sorption occurred in the beginning and it reached equilibrium after 40 minutes on the oyster shell and 4 hour on the sewage treatment sludge and water treatment sludge. Results of Freundlich isotherms indicated that sewage treatment sludge could be properly used as an adsorbent for heavy metals and sorption strength of heavy metals was in the order of Pb > Cu > Cd. In the influence of pH on the adsorbents, sorption rate was more than 80% in pH 4 and most of heavy metals were adsorbed in pH 9. Adsorption rate of Cd decreased with decreasing pH and then adsorption rate of Cu was lower in soil.
        57.
        2005.09 KCI 등재 서비스 종료(열람 제한)
        The biosorption of dye, Rhodamine B(Rh-B), onto waste activated sludge was investigated. The biosorption capacity and contact time were shown as a simulation of dye adsorption equilibrium and kinetics models. We observed that biosorption of Rh-B occurred rapidly less than 4hr. These experimental data could be better fitted by a pseudo-second-order rate equation than a pseudo-first-order rate equation. The equilibrium dependence between biosorption capacity and initial concentration of Rh-B was estimated and it was found that the equilibrium data of biosorption were fitted by four kinds of model such as Langmuir, Freundlich, Redlich- Peterson, and Koble-Corrigan model. The average percentage errors, ε(%), observed between experimental and predicted values by above each model were 21.19%, 9.97%, 10.10% and 11.76%, respectively, indicating that Freundlich and Redlich-Peterson model could be fitted more accrately than other models.
        58.
        2005.07 KCI 등재 서비스 종료(열람 제한)
        Waste sludge may be used to recovery wastewater contaminated with heavy metals. The waste sludge is an inexpensive readily available source of biomass for biosorption with metal-bearing wastewater. The biosorption of heavy metals such as Pb(II), Cu(II), Cr(II), and Cd(II) onto waste sludge was investigated in batch experiments and waste sludge loaded heavy metals was separated by dissolved air flotation. The biosorption equibria of heavy metals could be described by Langmuir and Freundich isotherms. The adsorption capacity for waste sludge was in the sequence of Pb(II)>Cr(II)>Cu(II)>Cd(II). The system attained equilibrium about 20 min. The Langmuir and Freundlich adsorption model effectively described the biosorption equilibrium of Cu(II) and Cr(II) ions on waste sludge. Maximum adsorption capacity of Cu(II) and Cr(II) were 196.08 and 158.73 mg/g, respectively. Solid-liquid separation efficiencies were kept above 95% on waste sludge loaded heavy metals, and were decreased with pH increasing.
        59.
        2004.07 KCI 등재 서비스 종료(열람 제한)
        The properties of biosorption of dye(Rhodmine B) was investigated to figure out the effects of temperature as a function of dye concentration and sludge concentration by the Langmuir and Lagergen adsorption model. It was found that the uptake capacity of biosorption was increased at low temperature. The Langmuir adsorption model was found suitable for describing the biosorption of the dye. The experimental results indicated that the dye uptake process followed the pseudo-first-order kinetics.
        60.
        2002.10 KCI 등재 서비스 종료(열람 제한)
        The objectives of this study were to investigate the desulfurization kinetics of paper sludge and limestone in a fluidized bed reactor according to bed temperature and air velocity. The experimental results were presented as follows ; First, the bed temperature had a great influence on the desulfurization efficiency of limestone and paper sludge. In paper sludge, the optimum condition in desulfurization temperature was at 800℃ and in limestone, that was at 850℃ or 900℃. Second, as air velocity increased, the desulfurization efficiency(or the absorbed amount of sulfur dioxide) by limestone and paper sludge decreased. And the absorbed amount of sulfur dioxide by paper sludge was larger than that of by limestone. Third, as the velocity increased and the optimum desulfurization temperature became, ks and the removal efficiency increased. So, ks, kd highly depended on the air velocity and bed temperature.
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