• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.91-95
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• 2003

There is a problem to be solved for improvement of durability and safety supervision. When you do the waterproofing and anticorrosive work of main concrete from the design stage, the material and method of construction need to be correctly applied to appropriate circumstance conditions. Epoxy have mostly been used for concrete water tank structure. Lately, lots of subjects on adaption of polyurea resin waterproofing and anticorrosive are under discussion. Then, we attempt to approach by evaluating and comparing every capabilities with another waterproofs in this study. Performance evaluation items include the adherence performance. the imprint of seal performance, temperature dependence performance. promotion westernizing ability, inner chemical performance. drinking water eruptive performance. Through the experiment analysis, we found that the polyurea resin waterproofing membrane is dominantly superior to other waterproofs. According to this study, we suggest the polyurea resin waterproofing membrane as a new waterproofing material for concrete structure.

• Analytical Science and Technology
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• v.19 no.4
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• pp.290-300
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• 2006

Disinfection by-products(DBPs), such as volatile trihalomethanes and the nonvolatile organochlorine acids, created by chlorination have been extensively studied. However MX which contributes 20-50% of the mutagenic activity in drinking water began to people's attention since 1990. Its chemical name is 3-chloro-4-dichloromethyl-5-hydroxy-2(5H)-furanone. According to WHO guidelines its concentration should be controlled, but its value has not been set up. Due to analytical difficulties in measuring this compound at such a low concentrations and lack of information on toxicity to human. Because concentration (ng/L) of MX in drinking water is low traditional testing methods are ineffective. Therefore this study compared LLE and SPE and have chosen SPE to improve preconcentration. MX has been identified in chlorinated drinking water samples in several countries but not in korea Therefore this study analyzed concentration of MX in different water sources and in spring water. This study examined the causes of changing MX content. Chlorine dosage, seasons, water temperature and distance from the source was all discoverd to be relavant. MX was analyzed in various treatment to find optimum disinfection methods. The outcome was that the concentration of MX was minimized when using biological activated carbon-O3 and granular activated carbon.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.3
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• pp.311-319
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• 1999

In Korea accelerated industry development and urbanization during the last three decades have led serious water pollution problems in many parts of the nation. Especially in the regions of west and south coast have low fresh water in the dry season of spring and summer. In the place isolated from land it is important to secure the fresh water for drinking and general service. This study is concerned on the thermal system design to develop low-pressure evaporation type fresh water gen-erator of capacity 1 ton/day using the heat source of non-operating boiler in the season of spring and summer. The results obtained from this study are as follows. the water quantitieds generated from experi-mental evaporator showed good coincidence with the calculated values. The maximum production quantity was 1.38ton/day at pressure 40mmHg abs. and temperature $80^{\circ}C$.

• Journal of the Korean Chemical Society
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• v.44 no.3
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• pp.220-228
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• 2000

This study deals with the water qualities of Dalgi mineral spring in Cheongsong district.Water samples which were taken from upper, middle and bottorn spring sites were tested for twenty eight important water quality items including minerals, essential and/or toxic trace elements, and the analytical items to affect the taste of mineral water, seasonally from May 1999 to February 2000 The results obtained wereas follows:Each spring site showed much difference in major items. Bottom spring water showed higher value of Mg and Na than others. Middle spring water showed the highest value in all of the items except Mg and Na. The concentration of Hardness, Fe and Mn in mineral water were over than the normal standard for drinking water, but these items are not specified for the mineral water. As, Cd, $Cr^{6+}$ and Hg were not found and Pb was found ln trace level. All of the items proved nearly constant during the four seasons except water temperature. The contribution of mineral water to the nutrition of human was calculated in order to investigate the health effect of drinking water on the bases of Required Daily Allowance,one liter of water drinking and the mineral concentration of the bottom spring. The percentage of consumable minerals of Ca, Mg, Na, K, Mn,Zn and Fe were 35.05,36.43,5.88∼10.63,0.19∼0.57,21.86∼43.72,0.65, and 95.l respectively. This means Dalgl mineral water is pIenty of iron mineral. The K and O indexes of mineraI water appeared to be good for healthy and delicious water.

• Korean Journal of Poultry Science
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• v.21 no.2
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• pp.93-99
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• 1994

Chickens subjected to heat stress decrease their heat production by consuming less feed. The lowered feed intake naturally brings about decreased production performance of chicken. The only exception to this is the increased survivability. Birds drink less when they eat less. In hot enviror-mental temperature, chicken need more water for increased heat loss through evaporation an increased urine excretion. Thus, the increased water intake may alleviate the heat stress of chicken. Various electrolytes supplementation to feed or drinking water can alleviate the heat stress of chicken by their effect of increasing water intake. Lasalocid, an ionophorous coccidiostat, was found to have the effect of increasing water consumption of chicken, thereby improving the lowered production performance of heat-stressed chicken. Finally, dietary fiber could be another possible element which can exert beneficial effects on heat-stressed chicken.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.3
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• pp.129-138
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• 1978

The contents of inorganic conservative constituents in the downstream water were determined in spring tides of every month from May 1977 to April 1978 at eight stations of Nagdong River. Samples were taken at the intervals of one or two hours from 7 a. m. to 7 p. m. at each station. Annual ranges and means of the chemical constituents over all the stations except station one, Kupo, ate as follows: pH 6.4-9.3, 7.7; electrical conductivity $0.085-0.345\times10^3\;\mu\mho/cm,\;0.196\times10^3\;\mu\mho/cm;$ chloride 5.8-50.0ppm, 17.7ppm: fluoride ND-0.19 ppm, 0.06 ppm: sulfate 5.5-41.1 ppm, 20.7 ppm; calcium 6-26 ppm, 17 ppm; magnesium 2.0-12.8 ppm, 5.1 ppm; sodium 7-26 ppm, 13 ppm; potassium 1.4-3.8 pprn, 2.3 ppm respectively. The seasonal variations of contents of the chemical constituents were not large and showed nearly definite values at all the stations except station one, Kupo. At station one, seasonal variations were large and the contents were excessively high due to inflow of seawater compared with other stations. The values over 50 ppm in chloride were not determined during the determination period at Mul Geum where the intake station for Busan city water is located. Most constituents except pH and fluoride were over the criteria for drinking water at Kupo, while at other stations only pH value was exceeded the upper limit of the criterion especially in summer period. The pH values tended to increase in the afternoon when water temperature was high. The chloride concentration was shown the highest value at station one, Kupo, with about 2 hours delay after high water of Busan harbour and 3-3.5 hours at Mul Geum.

• Journal of Soil and Groundwater Environment
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• v.18 no.3
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• pp.52-57
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• 2013

Radon, which is one of the radioactive elements in the natural world, exists in the atmosphere and water. When this element inflows into the human body, it carries the risks of developing lung cancer and stomach cancer. Therefore, in this study, an effective 10 L scaled reactor was produced to mitigate radon in water and the radon mitigation efficiency in water following the changes in water temperature and amount of aeration were evaluated. Based on this, the radon mitigation efficiency (SRRR; Specific radon removal rate) was derived per unit air volume. According to the study result, when water temperature increased from $10^{\circ}C$ to $16^{\circ}C$, the SRRR value increased from 95 $nCi/m^3{\cdot}L$ to 134.4 $nCi/m^3{\cdot}L$, and when the amount of aeration increased from 0.2 L/min to 1 L/min, the SRRR value decreased from 198.1 $nCi/m^3{\cdot}L$ to 72.2 $nCi/m^3{\cdot}L$. Therefore, based on the experimental results, it is considered that it can be applied as a examination factor and objective indicator during the design of future radon-in-water mitigation systems.

• Journal of Environmental Impact Assessment
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• v.16 no.1
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• pp.15-26
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• 2007

Surface water is the main drinking water source in Korea. Algal bloom caused by phytoplankton in reservoir is common event in every summer season. To prevent or control the algal blooms, artificial circulation system has been adopted in many reservoirs, including Hoengseung reservoir. Total 7 hydraulic-gun-aerators were installed around the intake tower in Hoengseung reservoir since 2000. This study is to elucidate the effects of hydraulic-gun-aerators on phytoplankton bloom, pH, DO, temperature and evaluate the selective withdrawal and vertical distribution of phytoplankton by means of submersible fluorescence probe, which features high correlation with a standard ISO method (r=0.90, P<0.0001) for chlorophyll-a quantification.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.645-654
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• 2013

In this study, the management polices of micropollutants (MPs) were reviewed and the future management strategy was discussed considering climate change and etc. In Korea, the investigation of drinking water has been actively carried out for the priority contaminants as well as MPs. Recently river and lake waters have been also examined for MPs. However, the coverage and depth of the investigation is limited. Moreover, climate change is likely to increase air & water temperature and it will affect the hydrological cycle. Such changes may increase the residual concentrations of MPs in water system. As water reuse increases, the residual MPs of the recycled water may create public concerns. Thus, in a viewpoint of the precautionary principle, more stringent management of MPs is recommended for the drinking water and the body-contact water use. For the surface water, more studies are necessary to understand the ecological risk by MPs.

• Journal of Environmental Health Sciences
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• v.20 no.4
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• pp.53-59
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• 1994

Since trihalomethanes (THMs) and other volatile organic compounds (VOCs) were detected and measured in drinking water supplies in 1974, because of the frequent occurrence of these compounds and the potential health hazard they pose, several methods for detecting VOCs have been developed. The most widely accepted method for the analysis of THMs and other VOCs is a purgeand-trap method. In the analysis of VOCs by purge-and-trap,there are several factors which may give rise to errors. Some of the factors to be considered are purge time, carryover effect, cryofocusing temperature, and trap desorption temperature. In this study,many aspects of purge-and-trap were investigated. Understanding the sources of error makes it possible to adapt the analysis parameters to compensate for such effects.