• Journal of Korean Society on Water Environment
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• v.21 no.3
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• pp.256-262
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• 2005

The purpose of this study is to investigate the performances of organic removal and methane recovery by using a full scale two-phase anaerobic system. The full scale two-phase anaerobic process was consists of an acidogenic anaerobic baffled reactor (ABR) and a methanognic upflow anaerobic sludge blanket (UASB) reactor. The volumes of acidogenic and methanogenic reactors were designed to $28.3m^3$ and $75.3m^3$. The two-phase anaerobic system represented 60-82% of COD removal efficiency when the influent COD concentration was in the range of 7,150 to 16,270 mg/L after screening (average concentration is 10,280 mg/L). After steady-state, the effluent COD concentration in the methanogenic reactor showed $2,740{\pm}330 mg/L$ by representing average COD removal efficiency was $71.4{\pm}8.1%$ when the operating temperature was in the range of $19-32^{\circ}C$. The effluent SCOD concentration was in the range of 2,000-3,000 mg/L at the steady state while the volatile fatty acid concentration was not detected in the effluent. Meanwhile, the COD removal efficiency in the acidogenic reactor showed less than 5%. The acidogenic reactor played key roles to reduce a shock-loading when periodic shock loading was applied and to acidify influent organics. Due to the high concentration of alkalinity and high pH in the effluent of the methanogenic reactor, over 80% of methane in the biogas was produced consistently. More than 70% of methane was recovered from theoretical methane production of TCOD removed in this research. The produced gas can be directly used as a heat source to increase the reactor temperature.

• Journal of Environmental Science International
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• v.14 no.9
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• pp.843-849
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• 2005

The objective of this research was to investigate the removal efficiencies ofVOCs and odors with newly developed biofilter which was designed to sustain the biofilm constantly on the packed media. Initially, four types of media, for example, fiber, activated carbon, ceramic and the mixture of activated carbon and ceramic(AIC mixture J, were used for packed materials of biofilter. When ethylalcohol was selected as a test gas for media efficiency, fiber and AIC mixture had better removal efficiencies of ethyl alcohol than others. Removal efficiencies for acetaldehyde, ethyl alcohol, butylalcohol, ethylacetate and diethylamine in biofilter with fiber and AIC mixture as packed media were increased as the residence time increased. Butylalcohol, especially, showed the maximum removal efficiency among all used VOCs and odors. In case of ethyl acetate, the difference of removal efficiencies between low and high residence times was wide remarkably.

• Journal of Environmental Health Sciences
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• v.20 no.4
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• pp.36-44
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• 1994

A study was carried out in order to investigate the removal efficiencies and removal characteristics of heaw metals such as Pb, Cd, Cr, Cu in raw water by one of conventional water treatment processes. The coagulants used in this study were Alum and PAC. Three kinds of water samples were provided: kaolin water, kaolin water mixed with humic acid and raw water from Han River mixed with suspended matter deposited on raw water inlet pipe. Heaw metals were added to the water samples with their respective turbidity, and jar tests were performed. In the results from heaw metal removal studies, lead might be adsorbed or exchanged on the particle surface (SS) rather than react with organic matter added. Cadmium was affected on the dissolved organic matter. Chromium was affected by the both dissolved organic matter and SS concentration, and the restabilization and the enmeshment appeared at moderate (50~80 NTU) and high (100 NTU) turbidity as defined in this experimenL The removal efficiency of copper was relatively little affected by the dissolved organic matter but by SS concentration in comparison with other heavy metals. In these studies as to the raw water turbidities and concentration of heaw metals, it is proved out that the removal efficiency on heaw metals in both cases of PAC and Alum as coagulants was not significantly different.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.11-24
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• 2003

This paper presents the results of laboratory investigation performed to study the role of different air sparging system parameters on the removal of benzene from saturated soils and groundwater. A series of one-dimensional experiments was conducted with predetermined contaminant concentrations and predetermined injected airflow rates and pressures to investigate the effect of soil type and the use of pulsed air injection on air sparging removal efficiency. On the basis of these studies, two-dimensional air sparging remediation systems were investigated to determine the effect of soil heterogeneity on the removal of benzene from three different homogeneous and heterogeneous soil profiles. This study demonstrated that the grain size of the soils affects the air sparging removal efficiency. Additionally, it was observed that pulsed air injection did not offer any appreciable enhancement to contaminant removal for the coarse sand; however, substantial reduction in system operating time was observed for fine sand. The 2-D experiments showed that air injected in coarse sand profiles traveled in channels within a parabolic zone. In well-graded sand the zone of influence was found to be wider due to high permeability and increased tortuosity of this soil type. The influence zone of heterogeneous soil (well-graded sand between coarse sand) showed the hybrid airflow patterns of the individual soil test. Overall, the mechanism of contaminant removal using air sparging from different soil conditions have been determined and discussed.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.6
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• pp.745-753
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• 2007

By struvite and hydroxyapatite crystallization, was high concentration of nitrogen and phosphorus in wastewater simultaneously. Particularly, removal of nitrogen and phosphate for crystallization have been applied to landfill leachates and animal wastewater. The purpose of this study is to decide the optimum struvite crystallization factors, sequence of $Mg^{2+}$ addition, pH control and the molar ratio of $Mg^{2+}$ over $PO_4^{3-}$. In conclusion, dosage of the magnesium followed by pH control formed magnesium hydroxide, so pH was decreased. Therefore, pH adjustment should followed by after magnesium dosage and then pH should be adjusted to 11. Over pH 10, it was not good for struvite crystallization efficiency by side reaction. Following of the $Mg^{2+}$ and the $PO_4^{3-}$ are dosed excessively, the removal efficiency of the $NH_4^+$ increased. A molar ratio of $Mg^{2+}:NH_4^+:PO_4^{3-}$, 1.3:1:1.3 was the most on effective for $NH_4^+$ removal at pH 9.5. But for the perfect removal $NH_4^+$, it is thought to be that molar ratio should be 2:1:2.

• Journal of environmental and Sanitary engineering
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• v.17 no.2
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• pp.40-47
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• 2002

In this study, water hyacinth plants(Eichhornia crassipes), water parsley(Oenanthe javanica) and Lemna paucicostate were used to treat contaminants such as COD, T-N and T-P in far m·fishing village wastewater. The results were as follows : In the batch system experiment, water hyacinth was showed at the high removal efficiency in the 173∼412kgCOD/ha·day concentration that is rather than 260mg/1 of the high concentration. The next is Oenanthe javanica, Lemna. Oenanthe javanica was showed the high removal efficiency in the 96∼173kgCOD/ha·day concentration that is less than 260mg/1 of the low concentration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.169-172
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• 1999

In this experimental study we Proposed the double dielectric barrier discharge (DDBD) reactor to produce as high an electric field as possible. The experiment are conducted for applied voltage from 15 to 20[tV], flow gas rage at 2[1/min] and pulse rate at 120[pulses/s] and 240[pulses/s]. SPD connection of DDBD which combine the surface discharge with the silence discharge was most effective to reduce the NOx. In the decomposition efficiency per watt, the low pulse rate gave hotter efficiency than that of the high pulse rate. However in DeNOx rate, the high pulse rate gave better performance than that of the low pulse rate. NOx removal rate increased with increasing the applied voltage in all reactors.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.981-987
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• 2011

Biologically treated water contains a large quantity of organic matters and microorganisms which can cause various problems to membrane. The membrane fouling occurred by these reasons is hard to control by single physical cleaning. This study analyzes the efficiency of aeration with chemical backwashing and foulants removal during chemical backwashing. The cleaning efficiency improves when the chemical concentration is high and the contact time of chemical is long. Chemical backwashing with aeration shows exceptional cleaning efficiency which leads the physical cleaning is required during chemical backwashing since it forms flow inside the membrane submerged tank. From the foulants removal analysis, the particles such as turbidity and TOC removal rate increase when the aeration is applied. Dissolved matter of DOC and UV254 removal is dependent on higher chemical concentration. According to FTIR analysis, one of major foulants, the polysaccharide is controlled by the chemical backwashing with aeration condition.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.4
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• pp.497-502
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• 2012

Anaerobic Digestion Process is evaluated as efficient wastewater treatment process with the removal of high concentrations of organic waste and production of biogas. This study was performed using hybrid anaerobic hybrid reactor (AHR) which consists of anaerobic sludge blanket (UASB) and biofilm-coated filter media was applied for Palm Oil Mill Effluent (POME) for 80 days to know optimum removal efficiency and production of biogas by comparing each part which divided changing Organic Loading Rate (OLR). As a result of this study, the removal efficiency was 90.4 % when the organic loading rate of influent was 15 kg COD/$m^3$/day. Since organic loading rate was up to 20 kg COD/$m^3$/day, the removal rate declined 80.7%. Over loading of influent caused sludge expansion and overproduction of microorganism. Amount of biogas was collected 82.3 L/day and pH was remained 6.9 constantly with balance of alkalinity.

• Journal of Environmental Health Sciences
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• v.31 no.6
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• pp.483-488
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• 2005

The waste seashells were used for the removal of hydrogen sulfide from a hot gas stream. The sulphidation of waste seashells with $H_{2}$S was studied in a thermogravimetric analyzer at temperature between 600 and $800^{circ}C$. The desulfurization performance of the waste seashell sorbents was experimentally tested in a fixed bed reactor system. Sulfidation experiments performed under reaction conditions similar to those at the exit of a coal gasifier showed that preparation procedure and technique, the type and the amount of seashell, and the size of the seashell affect the $H_{2}$S removal capacity of the sorbents. The pore structure of fresh and sulfided seashell sorbents was analyzed using mercury porosimetry, nitrogen adsorption, and scanning electron microscopy (SEM). Measurements of the reaction of $H_{2}$S with waste seashells show that particles smaller than 0.631 mm can achieve high conversion to CaS. According to TGA and fixed bed reactor results, temperature had influenced on $H_{2}$S removal efficiency. As desulfurization temperature increased, desulfurization efficiency increased. Also, maximum desulfurization efficiency was observed at $800^{circ}C$. Desulfurization was related to calcinations temperature.