• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.13-25
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• 2007

The water treatment plants in Seoul Metropolitan Area, which are under Korea Water Resources Corporation(KOWACO)'s management, take water from Paldang Reservoir in Han River System for drinking water supply. There are taste and odor (T&O) problems in the finished water because the conventional treatment processes do not effectively remove the T&O compounds. As part of countermeasures for taste and odor control, KOWACO is planning to introduce advanced water treatment process such as ozone and GAC in near future. This study evaluated the removal characteristics of T&O and dissolved organic matter (DOM) to find design and operation parameters of advanced water treatment processes in a pilot-scale treatment plant. The GAC adsorption capacity for DOC in the two GAC system (GAC and $O_3$-GAC) at an EBCT of 14min was mostly exhausted after 9months. The differency of the removal efficiency of DOC between $O_3$-GAC and GAC increased with increasing operation time because the bioactivity in $O_3$-GAC process was enhanced by post-ozone process. Removal by conventional treatment was unable to reach the target TON(threshold odor number) of 3 but GAC systems at an EBCT(empty bed contact time) of 14 min were able to archive the target with few exception. During the high T&O episodes, PAC as a pretreatment together with GAC could be useful option for T&O control. However, substantial TON removal continued for more than two year (> 90,000 bed volumes). At the spiking of less concentration 26 to 61 ng/L in the influent of GAC systems, GAC absorber and $O_3$-GAC processes could meet the treatment target. The better spike control after 12 and 19 months of operation compared to that after 7 months of operation is a strong indication of biological control. The results presented in this study had shown that $O_3$-GAC process was found to be more effective for T&O control than GAC process. And the main removal mechanism in GAC systems were adsorption capacity and biodegradation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.141-144
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• 2006

This experiment investigated seed yield and grain quality of rice plants treated with different irrigation methods (water supply until complete saturation, field capacity, and surface soil crack) compared with a conventional irrigation method (inundation). Each treatment began 20 days after transplanting and ended 35 days after heading. There was an 8, 18 and 18% reduction in irrigation water in the three treatments, respectively. Rice yield with complete saturation treatment was similar to that of conventional irrigation, while those of field capacity and soil crack were less by 7 and 13%. The ratio of filled grain was lower and amylose content was higher in the water-saving irrigation than those from conventional irrigation.

• Parasites, Hosts and Diseases
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• v.48 no.3
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• pp.219-224
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• 2010

This study has been conducted to estimate the occurrence of Cryptosporidium oocysts in water supplies in the Metropolitan area of Seoul, South Korea, for 10 years from 2000 to 2009. Water samples were collected quarterly at 6 intakes in the Han River and its largest stream and 6 conventional Water Treatment Plants (WTPs) serving drinking water for 10 million people of Seoul. Cryptosporidium oocysts were found in 22.5% of intake water samples and arithmetic mean was 0.65 oocysts/10 L (range 0-22 oocysts/10 L). Although the annual mean of oocyst number was as low as 0.04-1.90 oocysts/10 L, 3 peaks in 2004 and 2007 were observed and the pollution level was a little higher in winter. The lowest density was observed at Paldang intake and the pollution level increased at Kuui and Jayang intakes. At the end of the largest stream, oocysts were found in 70% of collected samples (mean 5.71 oocysts/10 L) and it seemed that its joining the Han River resulted in the increase at Kuui intake and downstream. Oocyst removal by physical process exceeded 2.0-2.3 log and then all finished water samples collected at 6 WTPs were negative for Cryptosporidium in each 100 L sample for 10 years. These results suggested that domestic wastewater from the urban region could be a source of Cryptosporidium pollution and separating sewage systems adjacent to the intakes could be meaningful for some intakes having weakness related to parasitological water quality.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.443-447
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• 2001

A laboratory-scale electrodewatering system for enhancing conventional filter pressure dewatering by an electric field has been developed to decrease the water content of sludge generated in the wastewater treatment. It consists of a piston-typed filter press, a power supply and data acquisition system. The offset of electrodewatering is investigated as a function of applied pressure, applied voltage, sludge type and filtration time. Also the optimal conditions for maximizing the dewatering efficiency in the eletrodewatering system are investigated. Electric field strength and mechanical pressure are in the range of from 0 to 120 V/cm and from 98.1 to 392.4 kPa. The dewatering rates increased with increasing electric strength. These experiments produced a final sludge cake with water content of 60 wt% using electrodewatering technology, compared with a 80 wt% using pressure filtration alone. The conventional filtration system using the electrodewatering shows the potential to be effective method for improving dewatering Sludge.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.6
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• pp.596-604
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• 2005

This paper presents the work on evaluating the LCC (Life-Cycle Cost) of a heat pump system as unutilized energy system. The river water as an unutilized energy source was used for the heat source of heat pump system. LCC analysis is a concrete method for evaluating the economical efficiency of energy facilities of building. The present case study shows an example of adequate use of the LCC analysis on a heat pump system and conventional gas boiler and refrigerator for building heat supply. A life cycle of 20 years was used to calculated net present value of energy cost. Over a 20 year life cycle, the energy cost could be reduced by 612 million won if a heat pump system were used instead of a conventional boiler and an absorption refrigerator.

• Proceedings of the Korean Geotechical Society Conference
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• 1993.10b
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• pp.103-118
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• 1993

The application of T.B.M tunnelling has been progressively increased since the first entrance into Korea in 1985 and especially, its higher performance and safety is widely proved as a generalized tunnelling in hardrock tunnel construction, comparing wi th conventional method. This case announcement will be much helpful for your general understanding of T.B.M tunnelling and the development of tunneling technology by introducing the brief methods and construction results from the actual application cases of T.B.M tunnelling in Ulsan Water Supply Tunnel Project, the longest tunnel in Korea under construction by YOU ONE. Co.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.04a
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• pp.55-62
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• 1997

In Japan, the membrane filtration is becoming a common technology for municipal water supply system especially for small plant. 6 years before (1991), the national research project of membrane filtration for small plant has started. The project was named as "MAC 21", MEMBRANE AQUA CENTURY 21. In the project the Ministry of Health and Welfare, 8 universities and 18 water treatment plant companies have been involved. This was the first attempt to research a common theme in joint with government, universities and private companies. After three years, the guide line for membrane filtration application for small plant has been established. This has promoted to install some actual plant. And also, another joint research for "RESEARCH OF MEMBRANE FILTRATION FOR ADVANCED WATER TREATMENT" has started in 1994 and completed in March, 1997. The project was named as MAC21. In the former project the main objectives were removal of turbidity and bacteria from water. However, in new project the objective was establishment of the further advanced membrane filtration technology which would be applicable for trace chemical components removal such as tri-halo-methane pre-courser, agricultural chemicals removal, offensive smell and taste removal and virus removal. For the objectives, application of nanofiltration and hybrid-system, a combination of micro-filtration ultra-filtration with biological, ozone and activated carbon treatment process have been studied. In addition, application of membrane filtration for treatment of back-wash waste water originated from membrane filters and conventional sand filters has.been studied. At the end of March of this year, about 30 membrane filtration plants are actually supplying the water, the total treatment capacity is about 6,000 m$^{3}$/day and another 20 will be installed within one year.led within one year.

• Journal of Environmental Impact Assessment
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• v.9 no.3
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• pp.239-248
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• 2000

The aggravating water quality from the expansion of industrialization along with increasing population lead to develop more intensive physical measures to secure better drinking water quality. This study was mainly initiated to establish a water-pollutant buffering zone for the upper stream basin of Paldang--the major source area of drinking water for the metropolitan Seoul and suburban areas with a population more than 13 million. Two different criteria were considered in determining the buffering distance from the edge of the streamflow : 1km-width buffer zone for the special protection area which has been strictly controlled by the conventional laws for the protection of drinking water supply, and 500m-width buffer zone for the rest of the area. To delineate the exact boundaries of the water-pollutant buffering zone, GIS database was created integrating topography, hydrography, cadastral, and other related layers. The newly designated water-pollutant buffering zone would contribute to improve the water quality in a long term along with the conservation of the wet land. More study, however, should be made within the water-pollutant buffering zone such as the detailed survey of the pollutants, vegetation, and ecosystem for more effective management of the buffering zone.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.633-641
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• 2011

The Philippines is known for its abundant water resources such as the rainfall, where it has a mean annual rainfall range from 965 to 4,100mm. Due to the rapid urbanization of the country, the population in Metro Manila has been continuously increasing hence, the demand for a potable water supply also increases. To mitigate the scarcity of potable water supply, utilization of the water resources should be practiced. Rainwater harvesting is one way to utilize the rainfall runoff. This study analyzedthe potentiality of the rainwater harvesting on residential areas in Metro Manila. A water balance method based spreadsheet was used with input parameters including daily rainfall, catchment area, runoff coefficient, population and the water demand. The efficiency of the domestic water tank was analyzedusing the three different climatic conditions (i.e., minimum, median andmaximum annual rainfalls) and three different types of toilets (i.e., inefficient, conventional and dual-flush toilets). Furthermore, the overflow volume was used to determine which size of rainwater storage was more appropriate for the study area. The results of the study showed that for the three types of rainfall years, only the conventional and dual-flush toilets were suitable for the utilization of rainwater harvesting. The utilization of the $60m^3$ storage tank was sufficient for supplying the demandsof the 90 houses only for a small period of time, 3 months. Based from this study, to fully sustain the long-term water demand of the houses, the enlargement of the tank size having a capacity of 1,100 to $2,500m^3$ is ideal.

• Journal of the Korean Society of Industry Convergence
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• v.7 no.1
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• pp.63-68
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• 2004

There are a lot of manholes such as for water supply, sewage, telecommunication cable, traffic sign, electricity supply, and rainwater, etc. Conventional manholes installed on a road are impossible to adjust height, so that they should be entirely excavated to reinstall or repair. This entire excavation of a manhole causes too much time-consuming work, waste of resources, and obstruction of traffic. In this study, in order to solve the above mentioned problems, a cover, outer and inner parts of a manhole are integrated by gear-shaped parts located between outer and inner parts of a manhole. Mechanical design is performed to determine dimension of gear-shaped parts by Taguchi orthogonal array table. Cast molds for a gear-shaped manhole are also manufactured.