• Journal of Korean Society of Water and Wastewater
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• v.30 no.3
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• pp.233-240
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• 2016

Control degree and property changes of dissolved organic matter (DOM) were conducted by coagulation of chemical treatment for 2 sewage treatment plants with different technical methods. As the result, SUVA value of the second treated water (supernatant of the second settling pond after biological treatment) was increased and DOC was reduced in comparison with supplied raw water. And, SUVA value and DOC were reduced by coagulation after coagulation treatment of the second treated water. Properties of dissolved organic matter for 2 sewage treatment plants's DOC were divided. As the result, there was lots of hydrophilic component with hydrophilicity in case of plant A. In case of the second treated water, Plant A showed fulvic acid with little molecular weight was reduced among the hydrophobic component with hydrophobicity, but numic acide with lots of molecular weight was increased. However, in case of plant B, both fulvic acid with little molecular weight and humic acid with lots of molecular weight were increased among the hydrophobic components with hydrophilicity. Before the operation of phosphorus facility, properties of dissolved organic matter after biodegradation with effluent water showed hydrophilic components were reduced and hydrophobic components were increased. However, after coagulation treatment of the second treated water, hydrophilic components and hydrophobic components were outstandingly decreased or increased. During the biodegradation after coagulation treatment, hydrophilic components were significantly decreased and hydrophobic components were increased.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.648-653
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• 2010

Discharged pollution load for the management of Total Maximum Daily Loads (TMDLs) is calculated on the basis of rainfall data for reference year. Rainfall has an influence on discharged pollution load in unit watershed with combined sewer system. This study reviewed the status of discharged pollution load and rainfall conditions. We also investigated rainfall effects on discharged pollution load by analyzing change of the load in accordance with increase of rainfall. The change ratio of discharged pollution load was 18.6% while inflow load only 5.8% for 5 years from 2004 to 2008 in Daejeon district. The greatest rainfall and rain days were over 2 times than the least during the period. This change in rainfall could have great effect on discharged pollution load. The analysis showed that discharged pollution load increased 2.1 times in case rainfall increased 2 times and 1.2 times in case rain days increased 2 times. Rainfall effects, therefore, should be considered to make resonable evaluation of discharged pollution load in the assessment of annual performances.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.2-2
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• 2016

내외수 연계 도시 침수저감 능력향상 기술 연구단(내외수 연구단)에서는 내수침수로 인한 인명 및 재산피해를 최소화하고 내외수 연계 도시 침수저감 능력향상 기술 연구를 통한 도시 내배수 시스템 선진화를 이루어 홍수재해로부터 안전한 도시 구축을 달성하는데 주 목표을 두고 있다. 본 연구에서는 주 목표 달성을 위해 시범적으로 도림천 유역의 대림분구를 중심으로 2010년 9월 21일 호우사상에 대해 Case Study를 실시하였다. 먼저, Case 1은 홍수예보 시 활용될 모형의 정밀도를 검증하고자 실제 빗물펌프장의 운영을 포함한 모형을 구축 후 침수흔적도와 침수분포에 대한 비교를 실시하였다. Case 2는 Case 1에 펌프장의 펌프토출 효율 등과 같은 구조적인 방안을 적용, Case 3은 Case 1에 최적 펌프장 운영방안 등과 같은 비구조적인 방안을 적용, 마지막 Case 4는 구조적 방안과 비구조적 방안을 연계한 방안으로, 총 Case 1~에 대한 침수저감 능력평가를 실시하였다. 이는 향후 내외수 연구단의 성과를 실무에 적용으로써 침수피해 저감에 크게 기여할 것으로 판단된다.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.934-938
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• 2003

Flow analyses using FLUENT 5.4 code were performed to validate the application of the local bidirectional flow tube in case of water and air flow. In this study, sensitivity studies have been performed to optimize the design features of the bi-directional flow tube which can be applied for the various experimental conditions. 2-dimensional axisymmetric steady state flow analyses have been performed. By calculating the differential pressure at both the front and the rear hole of the flow tube, K values were evaluated. The K values show good linearity regardless of the tube sizes and the Re numbers in both water and air flow. And system pressure and water subcooling didn’'t affect the K values. Under the elevated pressure of 80bar with 80K water subcooling, the K value indicates a similar trend with the case of 2bar with 80K water subcooling.

• KCID journal
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• v.18 no.1
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• pp.68-80
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• 2011

To provide a operation rule curve for reservoir with low ratio of watershed area to paddy field area, Duckyong reservoir with watershed area of $15.8km^2$ and paddy field area of 1,071ha was selected, in which 4 meters are being heightened and full water levels will be increased from EL.26.0m to EL.30.0m, total water storages from 365.6M $m^3$ to 708.0M $m^3$. There was no operation rule curve that satisfied over 90% reliability of water supply in reservoir with watershed area of 1.48 times of paddy field area. The differences between observed and simulated reservoir daily water storages were minimized to determine parameters for simulating reservoir inflow in case of paddy field area of 550ha from 1991 to 2010. A operation rule curve was drawn to have a maximum storage with total water storage, which was in paddy field area of 700ha with ratio of 2.3 between watershed area and paddy field area. This case showed that annual irrigation water supply was 668M $m^3$ and instream flow of 57M $m^3$, water supply reliability of 55.6% in normal operation, and annual irrigation water supply was 605M $m^3$ and instream flow of 38M $m^3$, water supply reliability of 95.6% in withdrawal limited operation. Water supply reliabilities showed 35.6% without flood regulation and 17.8% with flood regulation in existing reservoir before heightening.

• Journal of Environmental Science International
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• v.22 no.7
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• pp.905-913
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• 2013

We compared the applicability and economical efficiency of peroxone process with those of ozone process in the existing water treatment plant on downstream of Nakdong River. After comparing the peroxone process for removing geosmin with the ozone process in lab scale test, peroxone process showed much higher removal efficiency than the ozone process at the same ozone dosage. Proper range of $H_2O_2/O_3$ ratio were 0.5~1.0 and the half-life of geosmin was about 5.5~6.8 min when the $H_2O_2/O_3$ ratio was set to 0.5 during 1~2 mg/L of ozone dosage. Peroxone process could reduce the ozone dosage about 50 to maximum 30% for the same geosmin removal efficiency compared to the ozone process in the pilot scale test. In case of 1,4-dioxane treatment, peroxone process could have 3~4 times higher efficiency than ozone process at the same ozone dosage. The results of estimating the economical efficiency of ozone and peroxone process for treating geosmin and 1,4-dioxane by using pilot scale test, in case of the removal target was set to 85% for these two materials, the cost of peroxane process could be reduced about 1.5 times compared to ozone process, and in the same production cost peroxone process could have 2~3 times higher removal efficiency than ozone process. The removal efficiency by peroxone process showed a large difference depending on the physicochemical characteristics of target materials and raw water, therefore detailed examination should be carried out before appling peroxone process.

• Journal of Korean Society of Rural Planning
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• v.24 no.2
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• pp.21-29
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• 2018

Riparian management has become important as stream water quality as well as riparian ecosystem gain more public attentions. The objective of this study was to determine riparian widths based on the functions of nutrient removal and wildlife habitat protection and to apply for the Jinwee stream area as a preliminary case. Nitrogen and phosphorus filtration efficiencies were considered in water quality aspect, while the habitat radii of amphibian and reptiles were used for wildlife conservation purpose. In addition, observation of endangered species and human impact on wildlife disturbance in riparian area were also taken into account in determining riparian widths. The stream confluence zone was emphasized by doubling the riparian widths as the focal point for wildlife habitat conservation. As the results, three different levels of riparian widths were proposed depending on the major riparian functions and applied to the Jinwee stream section as the case study. The proposed method can be used to determine riparian width in other stream areas based on different functional focus, ie, water quality or riparian conservation purposes.

• Journal of the Korean institute of surface engineering
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• v.40 no.6
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• pp.245-249
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• 2007

Amorphous IZO films were deposited on PET substrate by DC magnetron sputtering without substrate heating. In order to investigate effect of reactive gas addition on film properties, 0.2-0.4% of $H_2$ or $O_2$ gas was introduced during the deposition. Deposited IZO films were evaluated with mechanical property, electrical property, and water permeability. In the case of $H_2$ gas addition, mechanical property showed clear degradation compared to $O_2$ gas. In the case of $O_2$ gas, water permeability of the IZO film was increased compared to $H_2$ gas which could be attributed to the low adhesion of the film caused by bombardment of high energy negative oxygen ion. As a result, it is confirmed that water permeability of the film could be strongly affected by adhesion of the film.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1375-1384
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• 2010

Growth in population and urbanization has progressively increased the loading of pollutants from nonpoint sources as well as point sources. Especially in case of road regions such as city trunk road, national road and highway are rainfall and pollutants runoff intensive landuses since they are impervious and emit a lot of pollutants from vehicle activity. This research was conducted to investigate the nonpoint sources concentration and quantifying stormwater pollutants which are contained in rainfall runoff water. Three different monitoring sites in Jinju and Changwon city were equipped with an automatic rainfall gauge and flow meter for measuring rainfall and the volume of rainfall runoff. In the case of average EMC value, city trunk road was shown the highest value in target water quality items like as BOD, COD, SS, TN and TP. Or the amount of runoff loads by water quality items showed the highest value in city trunk road. And runoff load in city trunk road was 43.8 times high value compared to highway by value of city trunk road $356.7 mg/m^2$, highway $8.150 mg/m^2$, national road $19.99 mg/m^2$ in the case of BOD.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.918-921
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• 1992

A basic study on the discharge phenomenum of rod-to-rod microgap in the deionized water has been investigated with emphasis on the microgap spacing. The I-V charateristics for the case of ac and dc applied voltages had 3 different regions, a low conduction ohmic region, a medium conduction corona discharge region, and a high conduction arc discharge region. The corona discharge in the deionized water for the case of ac and de applied voltages had no different from the those in the air. But the arc discharge in the water occurred pulsative with sound which, however it is not clear, would be encounted due to the influences from the low temperature of the ambient water, vast of electrolytic generated electronegative gases(e.g. $O_2$, OH, O) and water molecules($H_2O$), and the space charge effects near the rod in the microgap from the ions of $H^+$, $OH^-$, $O_2^-$, etc, whose mobilities in the water are originally very low.