• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 가을 학술발표회 논문집
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• pp.241-246
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• 1999

In this research, electrokinetic remediation test was experimented with contaminated kaoline specimen at below, above the cation-exchange capacity of the mineral. The changes of the flow in electro-osmosis with open electrodes and current were presented, and lead removal results were evaluated through the extraction test. As a result, it was showed that removal efficiency was 20-30%, 67-87% In the anode As lead transport continues, the lead precipitation within a narrow zone very close to the cathode can go significantly high. This high lead precipitation near the cathode could block the flow path, decrease the conductivity, and thus the electroosmotic flow. The net effect will cause a decrease in the efficiency of electrokinetic processing. Therefore, in this study, citric acid and surfactant solution was used at the cathode as enhancement techniques.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
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• pp.226-229
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• 2001

For volume reduction of the wastewater generated on washing the soil contaminated with cobalt, recycling and reuse experiments of the wastewater were executed. Also. the soil remediation efficiency by repetitive washing with fresh citric acid was analyzed. The soil around TRIGA was sampled for the experiment. Results of recycling experiment by replacement-precipitation method were as follows. The remediation efficiency of 1st recycling wastewater was 97% and that of 2nd recycling wastewater was 94%. Also, To obtain remediation efficiency over than 90%, the 5th repetitive washing with fresh citric acid was needed.

• 대한기계학회논문집B
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• 제24권8호
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• pp.1069-1076
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• 2000

As the environmental problems grow, the regulation of the pollutants emitted from power plants increases. Most of the pollutants in particle phase are removed by particle removal facilities, but fine particles between 0.1 micron and I micron in diameter have a low removal efficiency compared to particles in other size ranges. Therefore the present concern has concentrated on the removal of those fine particles. The purpose of this study is to grow fine particles by condensation to the range larger than I micron. Theoretically the general dynamic equation is solved with an assumption that the particle size follows a log-normal distribution to calculate the temporal behavior of the size distribution. Experiments have been carried out to compare the results with the theoretical predictions. Particles grown by condensation are sampled by impactors and observed with SEM photographs.

• Water Engineering Research
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• 제3권1호
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• pp.1-8
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• 2002

Cloud seeding has not been used now to regulate water supplies in Korea and this results in losses to economy. The fastest experiments on precipitation enhancement in the world show that there are real possibilities to increase precipitation by 10-20%. Investigations of economic losses due to the lack of routine cloud seeding experiments in Korea have shown that they exceed about 100 million US dollars In 1999. Recommendations on cloud seeding activities including works on precipitation augmentation and prevention of heavy rains are presented. Spatial and temporal necessity to carry out this or that work is discussed.

• 상하수도학회지
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• 제18권4호
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• pp.470-479
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• 2004

The experimental conditions and relationships between parameters such as organic matter, aeration volume, aeration time, and precipitation time for the effective treatment of domestic wastewater were investigated. With the batch systems, the adsorption amount of unit microbe was measured with the change of MLSS concentration, precipitation time, and aeration amount. Theoretical adsorption amount of microbes was then numerically formulated by use of a SPSS multiple analysis as follows: $$Y=-0.0106(X_1)+0.07310(X_2)+42.705(X_3)+62.700$$ In this study, the amount of organisms to be removed in the range of MLSS concentration 2,000~4,500 mg/l were examined. In order to investigate the optimal condition of nitrification, the upper water in the biosorption stage was used as the initial experiment water. The results showed that the C/N ratio was 1.5 and the reaction time for the optimal nitrification was 1.5 hr. When the adsorption efficiency for microbe biosorption was 66%, the optimum denitrification efficiency was 83.3%. When the optimum parameters obtained from the batch experiment were applied to the lab-scale operation, the total retention time from the flow-in to flow-out was 10 hours and the removal efficiency was 93.8% for $COD_{cr}$ and 80.9% for TN. For the full-scale operation, the total retention time was 9.0 hours and the removal efficiency was 94.4% for BOD, 89.6% for $COD_{cr}$, 88.0% for TN, and 86.2% for TP.

• 한국자동차공학회논문집
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• 제15권2호
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• pp.151-158
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• 2007

Filtration studies, using simulated test nanoparticles or diesel nanoparticles, have been performed about Inconel foam filters for DPF combined with electrostatic precipitation. The simulated test particles were synthesized by laser ablation in the nitrogen atmosphere at the standard condition. The diesel particles were exhausted from the diesel engine driven on the condition of idle or load mode. Filtration efficiency of the metal foam filter is very low because most of particles are penetrated through the large pores of filter. However, the efficiency was considerably improved by applying the electric field to the filter and/or charging the nanoparticles. Nevertheless, the pressure drop of filter hardly increased because the filter-pores were not clogged by deposited particles and kept open.

• 대기
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• 제22권1호
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• pp.73-85
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• 2012

The collision efficiency data for collision between graupel or hail particles and cloud drops that take into account the differences of particle density are applied to the Takahashi cloud model. The original setting assumes that graupel or hail collision efficiency is the same as that of the cloud drops of the same volume. The Takahashi cloud model is run with the new collision efficiency data and the results are compared with those with the original. As an initial condition, a thermodynamic profile that can initiate strong convection is provided. Three different CCN concentration values and therefore three initial cloud drop spectra are prescribed that represent maritime (CCN concentration = 300 $cm^{-3}$), continental (1000 $cm^{-3}$) and extreme continental (5000 $cm^{-3}$) air masses to examine the aerosol effects on cloud and precipitation development. Increase of CCN concentration causes cloud drop sizes to decrease and cloud drop concentrations to increase. However, the concentration of ice particles decreases with the increase of CCN concentration because small drops are difficult to freeze. These general trends are well captured by both model runs (one with the new collision efficiency data and the other with the original) but there are significant differences: with the new data, the development of cloud and raindrop formation are delayed by (1) decrease of ice collision efficiency, (2) decrease of latent heat from riming process and (3) decrease of ice crystals generated by ice multiplication. These results indicate that the model run with the original collision efficiency data overestimates precipitation rates.

• 자원리싸이클링
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• 제14권6호
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• pp.16-20
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• 2005

구리, 니켈 그리고 코발트를 함유한 용액으로부터 구리를 선택적으로 분리하기 위하여 $Na_{2}S$를 첨가하여 구리를 CuS로 침전시키는 연구를 행하였다. 구리의 침전율은 용액의 pH가 높을수록, 첨가한 $Na_{2}S$의 양이 많을수록,농도가 낮을수록, 반응온도와 반응시간이 증가할수록 증가하였다. pH 1, $20\%\;Na_{2}S$ 첨가량이 구리의 3 당량비, 온도 $25^{\circ}C$ 그리고 반응시간 30분에서 구리의 침전율은 $94.1\%$이었으며 니켈과 코발트도 각각 $4.3\%$와 $4.5\%$가 침전되었다. 즉 일부 니켈과 코발트 이온이 같이 공침되기 때문에 정량적으로 구리만을 침전, 분리하는 것은 가능하지 않았다.

• 환경영향평가
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• 제20권2호
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• pp.227-234
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• 2011

In the study, CE-QUAL-W2 was used and its examination and correction were conducted targeting 2001 and 2003 when the condition of rainfall was contradicted. Using the proved model in 2003, a scenario was implemented with management of locations for dewatering outlets and actual data for dam management in 1987 when inflow and outflow level were almost same. In case of the scenario which the location of dewatering outlets was 5m higher than usual location, exclusion efficiency for turbid water inflow at the beginning of precipitation was good. In case of the scenario which the location of dewatering outlets was 10m lower than usual location, exclusion efficiency for excluding turbid water remained in a reservoir after the end of precipitation. However, the scenario applying dam management data in 1987, exclusion efficiency was relatively low. In the scenario, power-generating water release spot at EL.57m for first four days after the beginning of precipitation, EL.52m for 5th to 8th and EL.42m from 9th days. An analysis of the scenario reveals that both excessive days exceeded 30 NTU and average turbidity levels were decreased comparing before and after the alteration on outlets. The average turbidity levels were decreased by minimum of 55% to maximum of 70% and 30NTU exceeding days were decreased by 45 days at maximum. Also, since it could exclude most of turbid water in a reservoir before the destatifcation, the risk for turbid water evenly distributed in a reservoir along with turn-over could be decreased as well.

• 자원리싸이클링
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• 제25권3호
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• pp.63-73
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• 2016

본 연구에서는 해수로부터 마그네슘을 농축하기 위하여 세 가지 침전제(NaOH, 시멘트 킬른 더스트, 제지슬러지소각재)를 이용하여 마그네슘을 침전시키고, 황산을 이용하여 마그네슘을 용출하는 실험을 진행하였다. 사용한 침전제의 종류와 상관없이 침전반응 효율은 거의 100%이었고, 용출반응 효율은 77 - 89%로 비슷하였다. 용출액의 마그네슘 농도가 4975 - 5775 mg/L이었는데, 이것은 침전반응과 용출반응을 통해 해수의 마그네슘이 3.8 - 4.4배 농축되었음을 의미한다. 본 연구에서 침전제로 사용한 산업부산물의 반응효율은 거의 100%로 기존의 고가 침전제와 비슷하였다.