• 한국환경과학회지
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• 제20권7호
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• pp.919-927
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• 2011

A ecosystem model was applied for understanding of circulation process of state variables in marine ecosystem. A mass balance was conducted by calculating the physical process. The sensitivity analysis was conducted to know which coefficient is the most effective factor to the state variables in the model. The results of the mass balance indicate that the primary production was 58.6 ton C/day in the case of mass flux. DIN and DIP in nutrient ingestion of phytoplankton were each 7.9 ton N/day, 1.1 ton P/day. POC and DOC in mineralization of organic matter were each 10.8 ton C/day, 40.6 ton C/day. The results of sensitivity analysis showed that the maximum growth rate of phytoplankton was the most important factor for overall state variables. In the case of nutrients, Half saturation constant of DIN, and mineralization rate of DOM for COD were important factor.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권4호
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• pp.1-7
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• 2013

Subcritical water which acts as organic solvent with increasing temperature and pressure because dielectric constant and viscosity decrease can be used to remediate PAHs-contaminated soil. Factors influencing on extraction were studied with varying the water temperature $200{\sim}275^{\circ}C$, extraction time 0~90 min, flow rate 10~100 mL/min and pressure 3.9~10MPa. 300 g of soil sample which was contaminated with PAHs(naphthalene, phenanthrene, fluoranthene and pyrene; 423, 420, 539 and 428 mg/kg of initial concentration) was packed into the cell and placed to reactor and then the subcritical water was pumped through the cell for PAHs extraction. Naphthalene was removed almost 100% at relatively low temperature ($200^{\circ}C$). The removal rate of phenanthrene, fluoranthene, and pyrene increased by 8, 26, and 23% when the temperature increased from 200 to $275^{\circ}C$; and it was gradually increased as extraction time increased from 0 to 90 min. Decreasing removal rate when water flow rate increased from 10 to 30 mL/min, but there was no significant change after 30 mL/min. This is supposed due to channeling phenomenon. The pressure was not an effective factor for extraction of PAHs in this study. Based on the results, the importance of effective factor was in following sequence: temperature >> time > flow rate.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2002년도 Current Trends in Toxicological Sciences
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• pp.69-70
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• 2002

Arsenic (As) is a ubiquitous element found in several forms in foods and environmental media, such as soil, air, and water. The primary route of human exposure is through ingestion of arsenic-contaminated food and drinking water. The predominant form of arsenic in drinking water is inorganic arsenic, which is both highly toxic and readily bioavailable.(omitted)

• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2002년도 Current Trends in Toxicological Sciences
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• pp.69-70
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• 2002

• 한국환경복원기술학회지
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• 제8권3호
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• pp.43-52
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• 2005

Evaluations of the fish farm influences on stream water quality may provide basic informations on watershed management to reduce environmental impact due to fish farm development and to conserve stream water quality in forested watershed area. In this research influent, effluent water in the fish farm and stream water qualities around Mt. Baegun area were monitored seasonally for six years and the following results were obtained. Due to the increase of pH in effluent water from the fish farm it was believed that alkalization of stream water can be accelerated by large scale development of fish farms in the forested watershed area. Also, effluent water from the fish farm increase of EC higher than influent and stream water. As a result of regression analyses, pH, EC, DO, water temperature, total amount of cation and anion in influent and effluent water of fish farm show high significance.

• 상하수도학회지
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• 제32권6호
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• pp.507-515
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• 2018

The results of the survey on water utilization status, the wasted water factor, the awareness, and the education and promotional activities of water saving in Daejeon City are as follows: The percentage of using tap valve with a closure was 66% when showering. 74% of water was used with closing the tap valve when washing faces with no water needed, it was still considered that there existed a wasting water. The most wasting reasons of water were found to be shower, bath, and laundry in order. In the awareness of practicing tap water saving, 9.1% of respondents acted actively, 53.4% of them were trying to practice it, and more than 63% had a positive awareness. In the contents of practicing saving water, locking water when soaping while showering, non-laundry of small quantity, and using cups when brushing teeth were top priorities. About 50% of the reasons for saving water was to practice purely saving water, when saving for economic help was excluded. The level of water saving awareness was not high when considering that the ratio of usage without water saving equipment and installation, and using method was relatively high when moving in. In order to make usage of water saving equipment more common, it was deemed necessary to provide information on the purchase of water saving equipment and to promote and educate the efficiency of saving of related products. More than about 90% of the respondents responded that water saving education or promotional activities had an effect of improving water saving awareness. The most effective method of education and promotional activities was found to be 40.4% by mass media activities, and 21.7% by promotions through mobile devices.

• 환경영향평가
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• 제23권2호
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• pp.137-149
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• 2014

The purpose of this study is to investigate the dynamics of the Zacco platypus population among streams in the Gongjicheon water system, Korea from December 2010 to October 2011. In this study, fish fauna was collected 27 Species belonged to 9 Families. The legal protection species, such as a natural monument and endangered species was not collected. Korean endemic species was collected 6 species including to Z. koreanus. The ratio of Korean endemic species was 22.6%, and it was lower than 51.3% that average of Korean endemic species in the Hangang water system. About these status, we considered that Gongjicheon water system had lost of the unique characteristics of the Hangang water system by the anthropogenic disturbances. The result of analysis to length-weight relationship and condition factor(K) of Z. platypus population in the Gongjicheon water system, the regression coefficient value(b) to indication of growth degree of the population was 3.04 and the slope of the condition factor(K) to indication of corpulency had positive value, respectively. These results seems to be that the Z. platypus population is maintained to a little unstably. In addition, the values of the degree of growth and corpulence were very low than the other natural streams in the Hangang water system, so it considered that the many artificially stress factors are occurred in this study area. These results are similar to Fish Assessment Index(FAI) in the assessment for health of aquatic ecosystem. Therefore, we are considered to require precise investigation and sustained monitoring for the restorations of stream ecosystem in the Gongjicheon water system.

• 한국환경보건학회지
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• 제15권2호
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• pp.51-58
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• 1989

In order to estimate unit loading factors of N, and P for controlling eutrophication of Youngsan lake. This study was performed in 4 kinds of pollutant sources from domestic sewage, industrial waste water, livestock stall waste water and drainage of agricultural area during the period from april to october 1988. These results were as follows: 1. The sewage flow for domestic waste water was 191.2 l/capita, day and that of the gray and toilet waste water among the domestic waste water were shown 152.9 l/capita, day(80%) and 38.3 l/capita, day(20%), respectively. 2. The unit loading factor total nitrogen(T-N) for domestic waste water was 7.582g/capita, day, and that of the gray and toilet waste water among the domestic waste water were 1.826g/ capita, day(24.1%) and 5.756g/capita, day(75.9%), respectively. The other hand, the unit loading factors of total phosphorus(T-P) for domestic waste water was 0.925g/capita, day, and that of gray and toilet waste water among the domestic waste water were 0.470g/capita, day(50.8%) and 0.455g/capita, day(49.2%), respectively. 3. In offering Price per million won, the T-P loading factor for drinking manufacture, confectionery manufacture, beer-manufacture and fibre manufacture in the industrial pollutant sources estimate to be 0.350g/day, 0.099g/day, 32.351g/day and 1.536g/day, while T-N loading factor about them in the industrial pollutant sources estimate to be 4.117g/day, 2.414g/day, 106.726g/day and 60.504g/day, respectively. 4. The T-P loading factor according to wash-water of milch cow and pig were 6.735g/day and 18.526g/day, in case of T-N they were 42.397g/day and 27.226g/day, respectively. 5. The T-P loading factor for pollutants drainage in the Paddy fields, fields and forests area were 0.082g/are, day, 0.014g/are, day and 0.002g/are, day, and the T-N loading factor were 0.309g/are, day, 0.158g/are, day and 0.064g/are, day, respectively. The diffrent of the loading factor for pollutants discharges in the agricultural area were resulted from the rainful intensity, the rainful, the amount of fertilization manure, and etc.

• 대한환경공학회지
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• 제33권7호
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• pp.501-510
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• 2011

한강의 주요 14개 지류하천 유역의 수질오염원을 평가하고, 2007. 1~2009. 12의 하천 수질자료(14 data set)로 SPSS-17.0을 이용하여 하천별 수질 특성을 평가하였다. 시 공간변화에 대한 군집 분석을 실시한 결과 공간변화에 따라 4그룹으로 평가되었으며, 유역의 오염원 종류 및 밀도가 군집분류에 가장 큰 영향을 미치는 것으로 나타났다. 시간변화에 따라 여름에서 가을까지(7~10월)와 겨울에서 초여름까지(11~6월)의 2그룹으로 분류되어 강우와 기온 그리고 부영양화 현상이 군집화에 기여하는 것으로 평가되었다. 조사대상 하천의 수질오염 요인은 유기물질 영양염류 세균오염요인과 하천 내 물질대사요인으로(71~90%) 설명되었고, 계절에 따라 주요인(수질오염물질)은 변화하는 것으로 나타났다. 각 하천의 수질특성은 요인과 유역 오염원을 같이 평가하였을 때 유용한 결과를 얻을 수 있었다.

• Membrane and Water Treatment
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• 제8권2호
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• pp.137-147
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• 2017

A water treatment utility in South Korea operates a large system of pressurized hollow fiber membrane (PHFM) modules. The optimal selection of membrane module for the full scale plant was critical issue and carried out using Risk-based Life Cycle Cost (RbLCC) analysis based on the historical data of operation and maintenance. The RbLCC analysis was used in the process of decision-making for replacing aged modules. The initial purchasing cost and the value at risk during operation were considered together. The failure of modules occurs stochastically depending on the physical deterioration with usage over time. The life span of module was used as a factor for the failure of Poisson's probability model, which was used to obtain the probability of failure during the operation. The RbLCC was calculated by combining the initial cost and the value at risk without its warranty term. Additionally, the properties of membrane were considered to select the optimum product. Results showed that the module's life span in the system was ten years (120 month) with safety factor. The optimum product was selected from six candidates membrane for a full scale water treatment facility. This method could be used to make the optimum and rational decision for the operation of membrane water purification facility.