• Resources Recycling
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• v.7 no.4
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• pp.55-63
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• 1998

The main purpose of the present study is to reduce quality variation of iron oxide for soft ferrite produced at hydrochloric acid facility )HAF) in a cold rolled mill factory. We investigated the factor of iron oxide quality variation, the operating condition of hydrochloric acid facility and the iron oxide quality with the production lot. Based on this information, we liad developed proper working plan for the diminution of iron oxide quality variation. To reduce iron oxide quality variation, the first priority is to control the picking steels, which seriously affect iron oxide quality variation, and then to separate generated waste acid. theretore, it was possible to reduce iron oxide quality variation with the proper operation of various kinds of waste acid tanks. We could produce iron oxide below 20 ppm SiO$_{2}$ content variation by operation after separation waste acid generated at TCM line.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2001.10a
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• pp.203-206
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• 2001

Finding the optimal solution in the river water quality management system is very hard with the non-linearity of the water quality model. Many suggested methods for that using the linear programming, non-linear programming and dynamic programming, are failed to give an optimal solution of sufficient accuracy and satisfaction. We studied a method to find a solution optimizing the river water quality management in the aspect of the efficiency and the cost of the waste water treatment facilities satisfying the water Quality goals. In the suggested method, we use the QUAL2E water quality model and the genetic algorithm. A brief result of the project to optimize the water quality management in the Youngsan river is presented.

• Journal of Korean Society of Water and Wastewater
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• v.12 no.3
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• pp.41-47
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• 1998

Doam Lake is located around the pasture area and Yongpyung Resort. Because of the waste load of domestic animals, nutrient concentration of the stream is high. In this study, waste load of Doam Lake watershed is calculated, and QUAL2E model is applied to the upper part of the Songcheon to calculate the input boundary concentration of Doam Lake. And WASP5 model is applied for the water quality modeling of Doam lake. The results indicate that advanced treatment of domestic animal wastes is necessary for the lake water quality management.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.04a
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• pp.197-202
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• 1994

This study is designed for analyzing the physical properties of grading, shape, specific gravity and etcetera of mine-waste as the aggregate of concrete when mine waste is crushed by jaw crusher, and is aimed presenting the using the possibility, content and reference data for the quality control of practical use on the concrete using the mine-waste aggregate.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.111-114
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• 2001

This study is a fundamental research for recycling waste vinyl in asphalt concrete mixture for roadway pavement. The mixing method and proper content of waste polyethylene(PE) film were determined through preliminary mix design. This study used 2-type aggregate gradations and two-type waste PE films. The mixtures were applied for a test pavement on a rural road. Quality evaluation of the asphalt concrete confirmed that waste vinyl asphalt concrete was applicable to road pavement.

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.160-167
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• 1996

The construction waste concrete produce from the demolished concrete structures. These waste concrete materials are useful and valuable for fill and subgrade and are considered to use as the subgrade material of the road. To use the subgrade of the road with the waste concrete, the several experiments involved with compaction test and laboratory C. B. R. etc. are performed. These experiments are compared with criteria of the road construction manual. It is shown that the quality of the construction waste concrete satisfies that of the subgrade mentioned in the road construction manual.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.631-636
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• 2002

This study shows basic data for using as the structural lightweight aggregate. This will be the procedural method of recycling environmental close waste PET bottle lightweight aggregate(PBLA) that is rapidly increased the amount of production of waste PET bottle recently, the quality of developed PBLA and the fundamental properties by analyzing of mortar containing with PBLA. After experiment, the result shows the PBLA quality that have oven dry specific gravity of 1.39, unit volume weight of 844 kg/m$^3$ and absorption rate of 0% is satisfied with qualify regulation of lightweight aggregate. The flowability of mortar containing PBLA is increased maximum 16% with increasing mixing ratio of PBLA, however the compressive strength of mortar is decreased maximum 35% with increasing mixing ratio of PBLA.

• Journal of environmental and Sanitary engineering
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• v.16 no.2
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• pp.56-62
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• 2001

This study is carried out to investigate the water quality changes in Busan Metropolitan streams, The results are as follows. The level of organic contaminants($BOD_{5}$ and $COD_{Mn}$) is found to be low and does not show seasonal variation in domestic waste water streams. But, the level of organic contaminants in industrial waste water streams is relatively high and seems to be seasonally variable, which is affected by other factors. The nutrient materials, such as nitrogen(as T-N, about 20mg/L) and phosphorus(as T-P about 2.0mg/L), are abundant than Nak Dong River and the general trends of contaminants level are similar to those of organic contaminants. The chronic water qualities, including organic, nutrient contaminants levels, show that the loading rates in 1998 are smaller than the past(1983, 1992). And this trend is more evident in industrial waste water streams than domestic waste water streams.

• Korean Journal of Community Nutrition
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• v.5 no.2
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• pp.316-323
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• 2000

This study was carried out to evaluate nutritional quality of the dosirak severed by 3 Dosirak manufacturing establishment in Kangnung. The subjects of this study came from 3 different male high schools in Kangnung. The portion amounts of Dosirak were weighed and the food intake was measured by substracting the leftover from the averaged portion amount. The leftover was measured by a modified aggregate selection plate waste measurement technique. The nutrient intakes were analyzed by a computer aided nutritional analysis program for professionals(CAN pro). The menu of the dosirak was too simple. The total amount of Dosirak was 714g and the percent of plate waste was 714g and the percent of plate waste was 7.2%. The male high school students were taking adequate energy, but the nutrients which did not meet 75% of the 1/3RDA(Recommended Dietary Allowances) were Ca, Fe, and vitamin B$_2$.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.1
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• pp.61-70
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• 2005

In order to reduce salt(as NaCl) contents in food waste and to improve the quality of discharged wastewater produced during the recycling process of food waste for the purpose of compost and feed stuff, a salt reduction process by added water into food waste was developed. The pilot plant with a rotary type salt reduction equipment to manage continuously 0.5 ton food waste per hour was constructed and the efficiency was tested. The amount of added water was calculated by the water content and the efficiency of dewatering process of food waste. Approximately 0.8 liter water per a kilogram of food waste was injected into the reactor in which food waste was pouring simultaneously, then diluted/mixed in a rotary reactor. About 1.1 liter of leachate including added water was generated, but the leachate contained a very high content of organic particles, so most particles were recovered by two step solid-liquid separation process. The first step was a gravitational filtering process using screens with a pore diameter of 1mm, and the second separation process was centrifugal process. Organic quality of food waste which had been desalted was maintained by inputting the entirely recovered organic particles. The efficiency of salt reduction of food waste was estimated by measuring a chloride anion by titration and salinity by a probe. The results by the two different measuring methods were always over 50%, and the quality of final wastewater was improved up to $200mg/{\ell}$ as TS(total solid) by an additional settling process after the two step solid-liquid separation process.