• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 춘계학술발표대회 논문집
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• pp.105-110
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• 2011

The doping procedure in crystalline silicon solar cell fabrication usually contains oxygen injection during drive-in process and removal of phosphorous silicate glass(PSG). In this paper, we studied the effect of oxygen injection and PSG on conversion efficiency of solar cell. The mono crystalline silicon wafers with $156{\times}156mm^2$, $200{\mu}m$, $0.5-3.0{\Omega}{\cdot}cm$ and p-type were used. After etching $7{\mu}m$ of the surface to form the pyramidal structure, the P(phosphorous) was injected into silicon wafer using diffusion furnace to make the emitter layer. After then, the silicon nitride was deposited by the PECVD with 80 nm thickness and 2.1 refractive index. The silver and aluminium electrodes for front and back sheet, respectively, were formed by screen-printing method, followed by firing in 400-425-450-550-$880^{\circ}C$ five-zone temperature conditions to make the ohmic contact. Solar cells with four different types were fabricated with/without oxygen injection and PSG removal. Solar cell that injected oxygen during the drive-in process and removed PSG after doping process showed the 17.9 % conversion efficiency which is best in this study. This solar cells showed $35.5mA/cm^2$ of the current density, 632 mV of the open circuit voltage and 79.5 % of the fill factor.

• 한국산학기술학회논문지
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• 제7권4호
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• pp.709-714
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• 2006

본 연구는 폐기물로 발생되는 부산석회 Core를 연속식 칼럼에 적용하여 수중의 인산염을 효과적으로 제거할 수 있는 방안을 찾고자 수행되었다. 부산석회와 인산염의 칼럼 반응에서 Hydroxyapatite을 형성하여 수중의 인산염을 제거할 수 있는 것으로 나타났으며 부산석회 Core size 1, 2에서 유입수의 인산염 농도에 관계없이 초기 11시간동안 90% 이상의 높은 제거율을 보였다. 또한 부산석회 Core size와 관계없이 유입수 유량이 증가할수록 파과시간이 줄어드는 것을 알 수 있었다.

• 한국물환경학회지
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• 제18권2호
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• pp.141-150
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• 2002

Two-stage membrane bioreactor using submerged hollow fiber membrane was applied in laboratory scale to treat nitrogen and phosphorus of domestic wastewater. Alum as the flocculant and adsorbent was added into the anaerobic basin of two-stage membrane bioreactor and mixed liquid of aerabic basin was recycled to the anaerobic basin for the purpose of nitrogen removal. Experiment was carried out to find removal efficient of phosphorous and nitrogen components in the mixed liquid, and the stability of the permeate flux and pressure of two-stage membrane bioreactor. In case of alum was added as the flocculant and adsorbent into the anaerobic basin, soluble phosphorus removal efficient was relatively higher and total permeate resistance(Rtot) was more increased out nitrogen removal efficient was lower as the result of lack of alkalinity and insufficient nitrification process than the case of alum was not added.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.414-417
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• 2000

기존의 BACC process의 가장 큰 단점은 탈질이 잘 이루어지지 않는다는 점인데 이것을 보완한 modified BACC process의 경우 실제오수를 사용하여 외부 반송비 따른 질소 및 인의 제거율을 살펴보면 외부 반송비가 200%일 때 $CODC_{Cr}$의 제거율은 평균 $96.3{\sim}95.7%$ 기존의 BACC process와 비슷하나 T-N 제거율은 $88.3{\sim}95.7%$로 월등히 우수한 결과를 보여주고 있다. 충진율 실험에서는 Table 2에서 보는 바와 같이 큰 차이는 없었다.

• 한국환경복원기술학회지
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• 제10권3호
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• pp.1-7
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• 2007

For waste water treatment, artificial wetland was constructed in 1998. The size of artificial wetland is 20m${\times}$200m, with sand and gravel as media and Phragmites japonica was implanted. The removal rate of BOD, TN, and TP were 86%, 33% and 25% from June 2004 to November 2005 respectively, while those were 88%, 38% and 55% in 1999. Organic materials and nitrogen compounds are still effectively removed, after 6 years of construction, but the removal efficiency of phosphorus compounds is reduced. So for sustaining of artificial wetland as waste water treatment system, the removal efficiency of phosphorus compounds must be elevated.

• 한국농공학회논문집
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• 제51권6호
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• pp.91-96
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• 2009

This study describes a zero discharge and reuse system developed for rural areas. The purpose of the system is decontamination of used irrigation water for down-stream usage and reuse of wastewater in rural villages for preventing water shortage problem expected to happen in near future. The system consists of anoxic, FES (Ferrous Electricity System), Oxic, Cralifier processes. The main feature of the system is to remove phosphorous by using Fe-ionizing module. Indoor experiments were undertaken with a trial product of the system to test its performance. The removal capacities of T-P, T-N, and BOD were examined. Also the proper time for the replacement of iron plate module was tested as well as the efficiency of T-P removal rate based on the usage of an automatic washing system for the iron plate. As results, the system showed very good water purification performances through obtaining the results of over 90% removal rates from T-P, BOD, and 67% from T-N. The proper time period for replacement of iron plate was maximum 2 years, and also efficiency of T-P removal rate found to be greatly influenced by the usage of an automatic washing system from the test.

• 상하수도학회지
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• 제23권1호
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• pp.113-119
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• 2009

The feasibility of using cork oak bark for phosphorus removal from wastewater was evaluated in this study. Recently, development of more cost-effective media while maintaining high efficiency in pollutants removal has received concern. Barks have a negative surface charge and, hence, tend to show a high affinity to bind cations, and they need to undergo chemical modification to increase their adsorption capacity of anions. Bark was hydrolyzed by HCl solution and it received modification using an aqueous solution of high molecular weight polyethylenimine(PEI). Surface modification with HCl and PEI resulted in a decrease of specific surface area of the bark from $1.932 m^2/g$ to $1.094 m^2/g$. The adsorption experiments were carried out in batch tests and the data were fitted to the Langmuir isotherm and Freundlich isotherm equations. Phosphate removal rate was higher at the lower solution pH possibly due to the form of phosphate ion in solution. For the initial phosphate concentration of 10 mg/L, maximum adsorption was 20.88 mg P/g at pH 3 and 12.02 mg P/g at pH 5. Mechanism of phosphorus sorption onto the HCl-PEI bark was examined through FT-IR spectrometer. Ion exchange between $NH^+$ and $H_2PO_4{^-}$ appeared to be a key mechanism of phosphate adsorption onto the HCl-PEI bark surface.

• 상하수도학회지
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• 제27권6호
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• pp.703-709
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• 2013

Among many microalgae cultivation types, heterotrophic culture with low cost carbon sources and energy saving culture method is crucial. A result of estimating the effects of pH on wastewater treatment using heterotrophic growing microalgae Chlorella sorokiniana shows that there was no difference in microalgae growth amount and nitrogen, phosphorus removal rate by wide range of pH(5 ~ 9). From pH 5 to 9, total nitrogen, phosphorous and glucose removal rates were 10.5 mg-N/L/d, 2 mg-P/L/d, 800 ~ 1000 mg/L respectively. This study reveals that C. sorokiniana cannot metabolite glycerol heterotrophically, however, glucose and acetate were proper carbon sources for growth and T-N, T-P and TOC removal. This research highlights the potential of heterotrophic microalgal growth with wastewater treatment plant with wide range of pH and carbon sources.

• 한국환경보건학회지
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• 제16권1호
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• pp.21-28
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• 1990

As a research for treatment of waste water by biological method, we investigated general characteristics of waste water and isolated some useful bacteria which effectively treated waste water. Compositions of waste water were analyzed to give COD 2060 ppm, PVA 560 ppm, T-N 50 ppm, T-P 3.3 ppm and PH 12. Also, we inverstigated optimum nutrients requirement and growth conditions by mixed culture as well as the effect of coagulants. The COD removal rate reached maximum state for 48 hrs culture at pH 7.0 and 30$^{\circ}$C. Alum as the coagulated was the most effective. The COD removal rate was also increased by supplementing 10 ppm phosphorous sources as additional nutrients. The COD of waste water was reduced to 10% of its initial value by the continuous culture. As a result of overall experiments the COD of effluents became about 100 ppm and final pH 7.

• 환경위생공학
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• 제16권1호
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• pp.102-107
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• 2001

This research was carried out investigate the removed T-P, T-N and anion surfactants using Autoclaved Lightweight Concrete(ALC) in wastewater treatment system. Effects of pH, TDS on aqueous solution was measured. Specific area which measured by BET was $27.66m^2/g$. The phosphorous, nitrogen and anion surfactants removal efficiencies were examined by using artificial waste water(T-P : 66~73mg/L, T-N : 56~136mg/L and anion surfactants : 10~31mg/L). The results showed that the ALC was effective material as a adsorbent due to the structure and porosity. It was found that anion surfactants removed was 85~95%, phosphate removed was 92% and nitrogen removed was 90% in artificial wastewater. Agitation process was more effective than aeration process in that case of nitrogen removal system using ALC.