• Environmental Engineering Research
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• v.16 no.3
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• pp.113-119
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• 2011

This study traces the origin, evolution, and current state-of-the-art of engineering-oriented water-quality management and modeling. Three attributes of polluted water underlie human concerns for water quality: rubbish (aesthetic impairment), stink (ecosystem impairment), and death (public health impairment). The historical roots of both modern environmental engineering and water-quality modeling are traced to the late nineteenth and early twentieth centuries when European and American engineers worked to control and manage urban wastewater. The subsequent evolution of water-quality modeling can be divided into four stages related to dissolved oxygen (1925-1960), computerization (1960-1970), eutrophication (1970-1977) and toxic substances (1977-1990). Current efforts to integrate these stages into unified holistic frameworks are described. The role of water-quality management and modeling for developing economies is outlined.

• Environmental Engineering Research
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• v.21 no.4
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• pp.319-332
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• 2016

Micropollutants are often discharged to surface waters through untreated wastewater from sewage treatment plants and wastewater treatment plants. The presence of micropollutants in surface waters is a serious concern because surface water is usually provided to water treatment plants (WTP) to produce drinking water. Many micropollutants can withstand conventional WTP systems and stay in tap water. In particular, pharmaceuticals and endocrine disruptors are examples of micropollutants that are detected at the drinking water, ppb, or even ppb level. A variety of techniques and processes, especially advanced oxidation processes, have been applied to remove micropollutants from water to control drinking water contamination. This paper reviews recent researches on the occurrence and removal of micropollutants in the aquatic environments and during water treatment processes.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.659-663
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• 2005

Many studies have been conducted to develop new technologies for arsenic removal and to reveal the levels of arsenic and other chemicals in rivers, lakes and ground waters. However, there are few studies dealing with such compounds in the total water system of the city, and the way of management of these compounds in the water system. Because the occurrence of these hazardous compounds, which are geological origins, is almost impossible to control, it is very important to manage these compounds in the water system. In this research, it was revealed that the risk of arsenic in the water treatment system of S city in Japan. As a results, the parameters such as Q in river and E260 in drinking water treatment plant is proposed as a new indicator with simple and rapid method for controling arsenic level.

• Journal of Korean Society on Water Environment
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• v.30 no.4
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• pp.429-440
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• 2014

This study was conducted to investigate the main cause of water quality deterioration during the spring season in the transition zone between the South Han River and the river-reservoir Paldang. A water quality model modified from QUAL2E (U.S.EPA) was used, and the model showed that eutrophication and algal production in the low flow season affected about 60% of the organic pollution at the downstream of the South Han River. This result means that phosphorus control is prior to external organic material management to ameliorate the deterioration of water quality in the water body.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.2
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• pp.228-234
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• 2004

Dissolved air flotation (DAF), in which suspended solids are removed from water by means of micro-size air bubbles raising slowly up in water and lifting solids from water (smaller than those) attached onto the micro-bubbles as well as those (larger than solids) being attached on these, have been used in water and wastewater since 1920s. The dissolved air flotation technology was originally based on the laminar flow conditions prevailing in water to be treated, but the latest development in that technology has led now to a situation, in which the flow conditions may also be turbulent ones in the modem dissolved air flotation units. Despite of that, the flotation phenomenon used in this unit operation for removal suspended solids from water or wastewater is still the same.

• Preventive Nutrition and Food Science
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• v.4 no.2
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• pp.134-138
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• 1999

The effects of dietary Coix(lacryma-jobi) water extract on the antioxidant enzyme activity in the liver and kidney of Sprague-Dawley rats were studied. Forty-five rats were fed for 3 weeks with either control diet or experimental diets that contain either Coix water extract or Coix water residue. Twenty percent of the carbohydrate was replaced with Coix water residue by dry weight in the water residue diet, while distilled water was replaced by Coix water extract to make a pellet-form diet in the Coix water extract diet. The levels of glutathione, glutathione-peroxidase, and glutathione-S-transferase activities in liver and kidney were measured . It has been found that glutathione, glutathione peroxidase, and glutathione-S-transferase enzyme activities from activities from liver and kidneyof the rats were enhanced in the group fed with Coix water extract.

• Journal of the Korean GEO-environmental Society
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• v.14 no.11
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• pp.55-63
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• 2013

Agricultural small dam reservoirs in Korea are vulnerable to flooding because of insufficient flood control capacity and deterioration such that reservoir water level is likely to rise rapidly and a large amount of water release quickly to downstream without flood warning. In this study, we performed hydrologic analysis to estimate design flood(200 years return period ${\times}1.2$) and also evaluated the effect of siphon spillway as a structural countermeasure for flood control and mitigation by applying reservoir routing to the Jipyeong reservoir, located in Sangju, Korea. The results show that the design flood was calculated at $284.3m^3/s$, and water level and water release decreased by 40cm and $91m^3/s$, respectively.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.568-574
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• 2011

Measuring tray as a component in irrigation control system using drainage electrodes was designed and applied for tomato perlite bed culture, and the effectiveness of the irrigation control system was investigated in terms of cultural development and cultivation costs. Five different types of measuring trays equipped with drainage electrodes were tested and the traditional tray was used as the control equipped with time clock. After the first experiment, "Tube-2" was removed because of instability of water content in the substrate. After second experiment, "Tube-1" was removed because of instability of water content in the substrate and low plant yields. In third experiment, "Up-Board" exhibited the best stability in water contents and yields as well as efficiencies in water and fertilizer utilization. The "Up-Board" was the most economical and the easiest system among the tested trays. Therefore, the "Up-Board" system was concluded as the excellent design to apply for the control method using drainage electrodes for tomato perlite bed culture.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.573-583
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• 2005

Fugitive dust, which is emitted in the ambient air without first passing through a stack or duct designed to control flow, is frequently generated by means of wind erosion from storage yards at Pohang Steel Wokrs. The size distribution of fugitive dust is mostly in the range of coarse particulate which is deposited as soon as emitted and less harm to human health; however $20\%$ of fugitive dust contains PM 10 known as one of most harmful airborne pollutant. Consequently, effective control and reduction of fugitive dust is strongly requested by the local society, but it is not easy so far because the generation and dispersion of fugitive dust highly depends on meteorological conditions, and it being occurred for irregularity. This research presented a fugitive dust control system for each meteorological condition by providing statistical prediction data obtained from a statistical analysis on the probability of generating the threshold velocity at which the fugitive dust begins to occur, and the frequency occurring by season and by time of the wind direction that can generate atmospheric pollution when the dispersed dust spreads to adjacent residential areas. The research also built a fugitive dust detection system which monitors the weather conditions surrounding storage yards and the changes in air quality on a real-time basis and issues a warning message by identifying a situation where the fugitive dust disperses outside the site boundary line so that appropriate measures can be taken on a timely basis. Furthermore, in respect to the spraying of water to prevent the generation of fugitive dust from the storage piles at the storage yard, an advanced statistical meteorological analysis on the weather conditions in Pohang area and a case study of fugitive dust dispersion toward outside of working field during $2002\∼2003$ were carried out in order to decide an optimal water-spraying time and the number of spraying that can prevent the origin of fugitive dust emission. The results of this research are expected to create extremely significant effects in improving surrounding environment through actual reduction of the fugitive dust produced from the storage yard of Pohang Steel Works by providing a high-tech warning system capable of constantly monitoring the leakage of fugitive dust and water-spray guidance that can maximize the water-spraying effects.

• Journal of Korean Society on Water Environment
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• v.32 no.1
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• pp.108-114
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• 2016

Sediment-laden water leads to water quality degradation in streams; therefore, best management practices must be implemented in the source area to control nonpoint source pollution. Field monitoring was implemented to measure precipitation, direct runoff, and sediment concentrations at a control plot and straw-applied plot to examine the effect on sediment reduction in this study. A hydrology model, which employs Curve Number (CN) to estimate direct runoff and the Universal Soil Loss Equation to estimate soil loss, was selected. Twenty-five storm events from October 2010 to July 2012 were observed at the control plot, and 14 storm events from April 2011 to July 2011 at the straw-applied plot. CN was calibrated for direct runoff, and the Nash-Sutcliffe efficiency and coefficient of determination were 0.66 and 0.68 at the control plot. Direct runoff at the straw-applied plot was calibrated using the percentage direct runoff reduction. The estimated reduction in sediment load by direct runoff reduction calibration alone was acceptable. Therefore, direct runoff-sediment load behaviors in a hydrology model should be considered to estimate sediment load and the reduction thereof.