• Asian-Australasian Journal of Animal Sciences
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• v.13 no.5
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• pp.698-701
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• 2000

To prevent surface and underground water pollution, wastewater treatment is essential. Four bench-scale activated sludge units (10 L operational volumes) were operated at 5, 10 and $20^{\circ}C$ for evaluation of treatment efficiencies with typical wastewater from swine housing. The units were set for a 24-hour cycle. As compared to the conventional process, high removal efficiencies for organic substances, nitrogen and phosphorus in swine wastewater were obtained simultaneously with an intermittent aeration process (lAP). The NOx-N produced during an aeration period was immediately reduced to nitrogen gas (e.g. $N_2$ or $N_2O$) in the subsequent non-aeration periods, and nitrification in aeration periods occurred smoothly. Under these conditions, phosphorus removal occurred with the release of phosphorus during the non-aeration periods followed by the excess uptake of phosphorus in the activated sludge during aeration periods. It was confirmed that the lAP had a better ability to remove pollutants under both low temperatures and high nitrogen loading conditions than the ordinary method did. In addition to that, the total emission of $N_2O$ from lAP was reduced to approximately 1/50 of the conventional process for the same loading. By adopting an adequate aeration programme for individual swine wastewater treatment, this system will provide a promising means for nitrogen and phosphorus control without pH control or addition of methanol.

• Biotechnology and Bioprocess Engineering:BBE
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• v.2 no.2
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• pp.77-81
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• 1997

Removal of nitrogen compound from waste water is essential and often accomplished by biological process. To prevent washout and to develop an efficient bioreactor, immobilization of sutibal microorganisms could be sensible approach. Strains and permeabilized cell encapsulated in cellulose nitrate microcapsules and immobilized on polystyrene films were prepared by the method described in the previous study. In the wastewater treatment system, nitrification of ammonia component is generally known as rate controlling step. To enhance the rate of nitrification, firstly nitrifying strains Nitrosomonas europaea(IFO14298), are permeabilized chemically, and immobilized on polystyrene films and secondly oxidation rates of strain system and permeabilized strain system are compared in the same condition. with 30 minute permeabilized cells, it took about 25 hours to oxidize 70% of ammonia in the solution, while it took about 40 hours to treat same amount of ammonia with untreated cells. All the immobilization procedures did not harm to the enzyme activity and no mass transfer resistance through the capsule well was shown. In the durability test of immobilized system, the system showed considerable activity for the repeated operation for 90 days. With these results, the system developed in this study showed the possibility to be used in the actual waste water treatment system.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.701-706
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• 2003

A study on the electrosorption of U(VI) onto porous activated carbon fibers (ACFs) was performed to treat uranium-containing lagoon sludge. Effective U(Ⅵ) removal is accomplished when a negative potential is applied to the activated carbon fiber(ACF) electrode. For a feed concentration of 100mg/L, the concentration of U(VI) in the cell effluent is reduced to less than 1mg/L. The adsorbed uranium could be deserted from the ACF by passing a 1M NaCl solution through the cell and applying a positive potential onto the electrode. The regeneration of ACF from the cycling experiments was confirmed.

• Journal of ILASS-Korea
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• v.7 no.2
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• pp.7-15
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• 2002

A particle flow visualization, electrostatic charging measurement and separation of triboelectrically charged particles in the external electric field by a fluidized bed tribocharger are conducted for the removal of PVC particles from mixed waste plastics. The laboratory-scale triboelectrostatic separation system consists of the fluidized bed tribocharger, a separation chamber, a collection chamber and a controller. PVC and PET particles can be imparted negative and positive surface charges respectively due to the difference of triboelectric charging series between particles and particles in the fluidized bed tribocharger, and can be separated by passing them through an external electric field. To visualize these charged particles, He-Ne laser is used with cylindrical lenses to generate a sheet beam. In the charging measurement, the particle motion analysis system (PMAS), capable of determining particle velocity and diameter. is used to non-intrusively measure particle behavior in high strength electric field. The average charge-to-mass ratios of PVC and PET particles are $1.4\;and\;1.2{\mu}C/kg$, respectively. The highly concentrated PVC (91.9%) can be recovered with a yield of about 96.1% from the mixture of PVC and PET materials for a single-stage processing. The triboelectrostatic separation system using the fluidized tribocharger shows the potential to be an effective method for removing PVC from mixed plastics for waste plastic recycling.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.6
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• pp.376-385
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• 2001

Considerable attention has been focused in recent years upon the field of biosorption for the removal of metal ions from aqeous effluents. Compared to other technologies, the advan-tages of biosortption are the high purity of the treated waste water and the cheap raw material. Really, the first major challenge for the biosorption field is to select the most promising types of biomass. Abundant biomass types either generated as a waste by-product of large-scale industrial fermentations particularly fungi or certain metal-binding seaweeds have gained importance in re-cent years due to their natural occurrence, low cost and, of course good performance in metal biosorption. Industrial solutions commonly contain multimetal systems or several organic and in organic substances that form complexes with metals at relatively high stability forming a very complex environment. When several components are present, interference and competition phe-nomena for sorption sites occur and lead to a more complex mathematical formulation of the process. The most optimal configuration for continuous flow-biosorption seems to the packed-bed column which gets gradually from the feed to the solution exit end. Owing to the com-petitive ion exchange taking place in the column, one or more of the metals present even at trace levels may overshot the acceptable limit in the column effluent before the breakthrough point of the trargeted metal. Occurrence of 'overshoot's and impact on havey metal removal has not been analyzed enough. New trends in biosorption are discussed in this review.

• Journal of environmental and Sanitary engineering
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• v.11 no.1
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• pp.83-91
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• 1996

It is not too much to say that the territorial inhabitants' concerns are wholly c concentrated on the environmental preservation-problem and development-problem in Korea given effect to the local self-government system. At a time like this I was studied the effect on nutrients removal through lighting period in aerobic high rate pond and we know that waste stabilization pond method is the most economical and energy saving wastewater treatment technology than others. At the results which was studied through operating the reactor-l artifically main-tained at a temperature, $25^{\circ}C$, a light intensity, 3000lux, and a lighting period, 24hrs and the reactor-2 artifically maintained at a tern야rature, $25^{\circ}C$ and a light intensity 3000lux, and a lighting period period, 12hrs, It has appeared for 24hrs.-lighting period -reactor-1 to be prior to the reactor-2. The attained results are that 1. reactor-1 is prior to reactor-2 on oxygen-generation 2. reactor-1 is prior to reactor-2 on algal production 3. COD removal efficiency, 90.76%, T-N removal efficiency, 80%, T-P removal e efficiency, 74.47 % in reactor-2, in reactor-1 COD removal efficiency, 94.85 %, T-N removal efficiency, 98.07%, T-P removal efficiency, 72.13% are, so the treatment efficiency of reactor-1 is more excellent than things of reactor-2 4. it appeared that the detention time is 8, 9days.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.841-849
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• 2012

The effluent quality of phosphorus is strengthened by the national standard to conserve water resources to lessen the eutrophication threat. The soluble phosphate in the wastewater effluent can be removed using the converter slag as solid waste produced through the steel making process. The experiments for removal efficiencies and removal constants were performed for this research with the artificial wastewater following several different conditions, particle size, phosphate concentration and initial pH. The correlation coefficients of Freundlich adsorption isothem were 0.9505 for $PS_A$, 0.9183 for $PS_B$, respectively. The removal efficiency was 87-94 % for $PS_A$ and 90-96 % for $PS_B$ respectively. The pH of the wastewater was elevated to pH 11.8 for the initial pH 8.5, phosphate removal efficiency was the highest as 84 % ~ 98 %. In case of 10 mg/L of the intial phosphate, the removal efficiency was 96 ~ 98 %. The more initial pH increases, the higher the reaction rate constant is.

• Environmental Engineering Research
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• v.21 no.2
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• pp.164-170
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• 2016

Since most of the existing wastewater treatment options lack the ability to treat micro-contaminants, the increased use of pharmaceuticals and personal care products (PPCPs) and release as human waste have become a serious concern in recent years. Constructed wetlands (CWs) are a low-cost technology for wastewater treatment, however, its performance in term of PPCPs removal has not yet been fully investigated. This study aimed to characterize the removal factors and efficiency of acetaminophen (ACT) removal by CWs. The results revealed the decreased concentrations of ACT with increasing hydraulic retention times (HRT) of 0, 3, 5 days. The contribution of removal factors was found to be varied with initial ACT concentration. At the low ACT concentration (i.e. 1 ppb), plant uptake was the dominant, followed by microbial and photolytic removal. In contrast, at the high ACT concentration (i.e. 100 ppb), microbial and photolytic removal were found as dominant factors. On the other hand, hydrogen peroxide ($H_2O_2$) concentration was found at higher level in the plant shoot than in the root probably due to occurrence of the Fenton reaction resulting in PPCPs removal.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1205-1214
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• 2005

This study was carried out to investigate the emission characteristics of volatile metals(Hg, As, Se) and semi volatile metals such as Pb from small and medium size municipal solid waste incinerators(MSWIs). The concentrations of Hg, Pb, As and Se in emission gas from small size waste incinerators were higher than those of medium size waste incinerators. This is probably due to less air pollutant control devices and high emission gas temperature of the small size waste incinerators relative to the medium size waste incinerators. Emission gas temperature from small and medium size waste incinerators were divided into 2 groups. The first group was about $100^{\circ}C$ and the second roup in the range of $400{\sim}700^{\circ}C$. The concentrations of emission gas at the second group were Hg $70.43\;{\mu}g/Sm^3$, Pb $0.94\;{\mu}g/Sm^3$, As $9.83\;{\mu}g/Sm^3$ and Se $5.05\;{\mu}g/Sm^3$. The concentrations of Hg, Pb, As and Se at the first group were lower than those found at the second group. Besides, the removal efficiencies of Hg in medium size waste incinerators were $55.2{\sim}95.9%$. Emission gas temperature reduction from waste heat boiler(WHB) contribute to control of Hg. Based on above results, we postulate that the temperature of flue gas should play a very important role in volatile metal control in small and medium size MSWIs. In order to improve the volatile metals removal efficiency, the temperature of cooling system must be controlled and the air pollution control device should be operated properly.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.4
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• pp.259-266
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• 2020

In this study, a pilot-scale (3 ㎥/day) membrane distillation (MD) process was operated to treat digestate produced from anaerobic digestion of livestock wastewater. In order to evaluate the performance and energy cost of MD process, it was compared with the pilot scale (10 ㎥/day) reverse osmosis (RO) process, expected competitive process, under same feed condition. As results, MD process shows stable permeate flux (average 10.1 L/㎡/hr) until 150 hours, whereas permeate flux of RO process was decreased from 5.3 to 1.5 L/㎡/hr within 24 hours. In the case of removal of COD, TN, and TP, MD process shows a high removal rate (98.7, 93.7, and 99% respectively) stably until 150 hours. However, in the case of RO process, removal rate was decreased from 91.6 to 69.5% in COD and from 93.7 to 76.0% in TP during 100 hours of operation. Removal rate of TN in RO process was fluctuated in the range of 34.5-62.9% (average 44.6%) during the operation. As a result of energy cost analysis, MD process using waste heat for heating the feed shows 18% lower cost compare with RO process. Thus, overall efficiency of the MD process is higher then that of the RO process in terms of permeate flux, removal rate of salts, and operating cost (in the case of using waste heat) in treating the anaerobic digestate of livestock wastewater.