• Journal of Sensor Science and Technology
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• v.30 no.5
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• pp.320-325
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• 2021

Biochemical oxygen demand (BOD) and chemical oxygen demand (COD) methods are conventional analytical methods to analyze water quality. Both of these methods are technically indirect measurement methods, require complicated preconditions, and are time-consuming. On the other hand, the total organic carbon (TOC) method is a direct and fast measurement method which is more intuitive and accurate than the BOD and COD methods. However, general TOC analysis methods involve complicated processes and high power consumption owing to the process of phase transition from liquid to gas by a high-temperature heater. Furthermore, periodic consumables are also required for the removal of inorganic carbon (IC). Titanium dioxide (TiO₂) is one of the most suitable photocatalysts for simple processes. Its usage involves low power consumption because it only reacts with the organic carbon (OC) without the requirement of any other reagents and extra processes. We investigated a TiO₂ photocatalyst-based TOC analysis for simple and affordable products. TiO₂-coated fiber substrate maintained under carbon included water was exposed to ultraviolet (UV) radiation of wavelength 365 nm. This method is suitable for the real-time monitoring of water pollution because of its fast reaction time. Its linear property is also sufficient to match the real value.

• Journal of Korea Water Resources Association
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• v.52 no.3
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• pp.207-217
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• 2019

This study aims at development and application of a facility that is capable of reducing pollution in water quality by reducing nonpoint source pollutants (NPSP). NPSP originated from the initial rainfall caused not only large catchment of urban area pass a river but also small watershed pass a stream. For this purpose, the performance tests carried out with the field models from the facility based on the preceding study. And the tests induced reduction efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (T-N) and suspended solid (SS), respectively. The average reduction efficiency obtained by time interval, and the result showed an excellent reduction performance. As a result, the facility satisfied reduction efficiency of NPSP of the proposed standard by the National Institute of Environmental Research, and thus it can be used in practical applications.

• Journal of Sensor Science and Technology
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• v.32 no.3
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• pp.140-146
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• 2023

Water quality is crucial for human health and the environment. Accurate measurement of the quantity of organic carbon in water is essential for water quality evaluation, identification of water pollution sources, and appropriate implementation of water treatment measures. Total organic carbon (TOC) analysis is an important tool for this purpose. Although other methods, such as chemical oxygen demand (COD) and biochemical oxygen demand (BOD) are also used to measure organic carbon in water, they have limitations that make TOC analysis a more favorable option in certain situations. For example, COD requires the use of toxic chemicals, and BOD is time-consuming and can produce inconsistent and unreliable results. In contrast, TOC analysis is rapid and reliable, providing accurate measurements of organic carbon content in water. However, common methods for TOC analysis can be complex and energy-intensive because of the use of high-temperature heaters for liquid-to-gas phase transitions and the use of acid, which present safety risks. This study focuses on a TOC analysis method using TiO₂ photocatalysis, which has several advantages over conventional TOC analysis methods, including its low cost and easy maintenance. For TiO₂, rutile and anatase powders are mixed with an inorganic binder and spray-coated onto a glass fiber substrate. The TiO₂ powder and inorganic binder solutions are adjusted to optimize the photocatalytic reaction performance. The TiO₂ photocatalysis method is a simple and low-power approach to TOC analysis, making it a promising alternative to commonly used TOC analysis methods. This study aims to contribute to the development of more efficient and cost-effective approaches for water quality analysis and management by exploring the effectiveness and reliability of the developed equipment.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.2
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• pp.99-104
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• 2010

The purpose of this study is to develop Sewage Treatment Plant that treat sewage which occurred in ship using fixed media method and to consider applicable to the Pilot Scale device of the STP regulations in MLTM(Ministry of Land, Transport and Maritime Affairs) and MEPC(Marine Environment Protection Committee). In test results, pH geometric mean was 7.68, $BOD_5$(Biochemical Oxygen Demand) geometric mean was 7.28 mg/l, $COD_{cr}$(Chemical Oxygen Demand) geometric mean was 48.39 mg/l, TSS(Total Suspended Solid) geometric mean was 18.00/l, Residual chlorine geometric mean was 0.19 mg/l, and E. coli geometric mean was 1CFU/100 ml. In addition, about 97.4% of $BOD_5$ was reduced, the $COD_{cr}$ reduction averaged 96.4%and the TSS reduction averaged 97.6%. STP have been determined by the MLTM and MEPC regulation of the marine pollution prevention equipment for performance testing product.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.420-431
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• 2010

Simple material budget models were developed to predict the dry season water quality for a river-type reservoir in Paldang, Republic of Korea. Of specific interest were the total phosphorus (TP), chlorophyll ${\alpha}$ (Chl. ${\alpha}$), 5-day biochemical oxygen demand (BOD), and chemical oxygen demand (COD). The models fit quite well with field data collected for 20 years and have enabled the identification of the origins of organic materials in the reservoir. The critical hydraulic load that determines the usability of phosphorus for algal production appeared to be about $1.5m\;d^{-1}$. When a hydraulic load was smaller than the critical value, the concentrations of $Chl.{\alpha}$, COD, and BOD in the reservoir water became sensitive to internal algal reactions such as growth, degradation, and settling. In spite of the recent intensive efforts for organic pollutant removal from major point sources by central and local governments, the water quality in the reservoir had not been improved. Instead, the concentration of COD increased. The model analysis indicated that this finding could be attributed to the continuing increase of the algal production in the reservoir and the allochthonous load from non-point sources. In particular, the concentrations of COD and BOD of algal origin during 2000~2007, each of which is comprised of approximately one half of the total, were approximately 2.5 times higher than those observed during 1988~1994 and approximately 1.3 times higher than those between 1995~1999. The results of this study suggested that it is necessary to reduce the algal bloom so as to improve the water quality of the reservoir.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.6
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• pp.88-98
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• 2007

The control of nonpoint source pollution from the urban paved areas with high imperviousness in is required to improve the water quality of aquatic resources. This research investigated the characteristics of urban runoffs and evaluate the effectiveness of the continuous deflective separation systems for stormwater best management practice. The systems were installed in the vicinity of a high-level road, an apartment complex, and the Cheonggye stream. Stormwater runoff was sampled in these sites. Biochemical oxygen demand ($BOD_5$), total suspended solid (TSS), total nitrogen (T-N), and total phosphorus (T-P) were analyzed. The removal efficiency of $BOD_5$, TSS, and T-P for the road was 10.9-81.0%, 11.7-93.4%, 0-37.5%, respectively. That of $BOD_5$, TSS, T-N, and T-P for the complex was 12.5-65.8%, 26.5-77.6%, 1.8-28.7%, and 20.0-37.5%, respectively. The abatement efficiency $BOD_5$, TSS, T-N, and T-P for the stream was 7.2-85.2%, 41.7-98.2%, 11.3-65.6%, and 2.0-71.5%, respectively. This study shows that the systems can be used to remove $BOD_5$ and TSS from urban runoffs efficiently.

• Journal of Korean Society of Water and Wastewater
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• v.9 no.4
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• pp.73-86
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• 1995

The propriety of the numerical model application was examined on Paldang resevoir and its inflow tributaries located in the center of the Korean peninsula and the long term water quality forecast of the oxygen profile was carried out in this syduy. The input data of the model was the capacity of the reservoir, catchment area, percolation, diffusion rate, vertical mixing rate, dissolution rate from the bottom of the reservoir, outflow of the resevoir, water quality measurement and meteorology data of the drainage basin, and the output result was the annual estimation value of the dissolved oxygen concentration and the biochemical oxygen demand. The modeling method is based on the measured or calculated boundary condition dividing the water area into several blocks from the macorscopic aspect and considering the mass balance in these blocks. As the result of the water quality forecast, it was expected that the water quality in Northern Han River and Paldang reservoir would maintain the recent level, but that the water quality in the Southern Han River and its inflow tributary would worsen below the grade 4 of the life environmental standard from around 2000 owing to the decrease of DO concentration and the increase of BOD concentration.

• Journal of Environmental Health Sciences
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• v.7 no.2
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• pp.97-105
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• 1981

Water Pollution of Gwangju Stream was examined for four months from 22 March 1981 to 7 June, 1981. For checking the water pollution, 6 sampling positions were selected 5 from main stream. We assumed that the water pollution of Gwangju stream was due to the organic materials, which came from the domestic sewage. The apparatus for this test were pH meter (Orion model 301), Dissolved Oxygen & Temperature meter(Delta model 1010). The results we obtained are as follows: 1. The average range for mid-stream(sp. 3, 4) was 3. 10~2.73ppm of Dissolved Oxygen(DO), 80.23~102.95ppm of Biochemical Oxygen Demand (BOD), 195. 10~165.90ppm of Suspended Solid (SS), 6.6~6.7 of pH. 2. The plankton identification in this survey period showed Cyanophyceae is 4 genera 5 species, Bacillariophycea 11 genera 14 species, Chlorophyceae 8 genera 15 species and Zooplankton 6 genera 7 species: total 29 genera 41 species. 3. To appear dominant plankton in polluted water, there were Paramecium, Euglena and Oscillatoria. 4. The results of biological water analysis were as follows: st. 1 was B-mesosaprobic to oligosaprobic, but st. 4 and st. 5 at stream in the midtown area seemed to be polysaprobic.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.155-160
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• 1994

A study of stream pollution caused by construction of the Industrial Complex in Agricultural Area of Chung Chong Nam Do were descrived here. The five main results of this studies are summerized. First, since 1988, among the companies moved in the industrial complex area, the number of electric and electronic companies have increased compared with food companies requiring much BOD. This Is very desirable to reduce the water pollution. Second, the average Biochemical Oxygen Demand(BOD) of Masan stream was the highest and it was decreased in the order of Yudug, Jo and Jungan stream. Third, although the concentration of heavy metals such as Cd and C $r^{6+}$ are not off the limit and the amount of it is small, it is desirable to introduce a chemical process to remove these metals. Fourth, since the wastewater from industrial complex area is the major factor in stream pollution, the laws associated with environmental protection should be enforced even then if the Industrial complex area with food and chemical companies produce wastewater less than 500ton/day. Fifth, it is required to improve a facilities which separete living wastewater from inderstrial wastewater In Kaya-gok and Nojang industrial complex areas.

• Environmental Engineering Research
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• v.17 no.2
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• pp.95-102
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• 2012

To evaluate the effect of the 4 major rivers restoration project in the Nakdong River to water quality of the river, the Environmental Fluid Dynamics Code (EFDC) and Water Quality Analysis Simulation Program (WASP), are applied in series. Results showed overall decrease in biochemical oxygen demand ($BOD_5$) concentrations and increase in chlorophyll-a concentrations, while total nitrogen and total phosphorous concentrations did not show significant changes, relatively. Decrease in $BOD_5$ concentrations seems to be influenced by an increased hydraulic residence time, which may allow more time for the degradation of organic material. Changes in Chlorophyll-a (Chl-a) concentration, due to the project were more significant for the upper stream areas that show relatively low Chl-a concentration ranges (less than 20 g/L). After the introduction of the Geumho River in the middle part of the Nakdong River, rapid growth of phytoplankton was observed. However, in this middle part of the Nakdong River, the ratio of Chl-a concentration change are less significant, compared to the upper stream areas, due to the project. In the lower stream area, Chl-a concentration decreased after the project. This seems to be resulted from the decreased light availability, due to increased depth, while the nutrient concentrations have been high enough to support phytoplankton growth.