• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.548-561
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• 2018

The objectives of this study were to construct a three-dimensional (3D) hydrodynamic and water quality model (EFDC) for the river reach between the Daecheong dam and the Sejong weir, which are directly affected by Gap and Miho streams located in the middle of the Geum River, and to evaluate the trophic status and water quality improvement effect according to the flow control and pollutant load reduction scenarios. The EFDC model was calibrated with the field data including waterlevel, temperature and water quality collected from September, 2012 to April, 2013. The model showed a good agreement with the field data and adequately replicated the spatial and temporal variations of water surface elevation, temperature and water quality. Especially, it was confirmed that spatial distributions of nutrients and algae biomass have wide variation of transverse direction. Also, from the analysis of algal growth limiting factor, it was found that phosphorous loadings from Gap and Miho streams to Sejong weir induce eutrophication and algal bloom. The scenario of pollutant load reduction from Gap and Miho streams showed a significant effect on the improvement of water quality; 4.7~18.2% for Chl-a, 5.4~21.9% for TP at Cheongwon-1 site, and 4.2~ 17.3% for Chl-a and 4.7~19.4% for TP at Yeongi site. In addition, the eutrophication index value, identifying the tropic status of the river, was improved. Meanwhile, flow control of Daecheong Dam and Sejong weir showed little effect on the improvement of water quality; 1.5~2.4% for Chl-a, 2.5~ 3.8% for TP at Cheongwon-1 site, and 1.2~2.1% for Chl-a and 0.9~1.5% for TP at Yeongi site. Therefore, improvement of the water quality in Gap and Miho streams is essential and a prerequirement to meet the target water quality level of the study area.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.44-50
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• 2001

This study was carried out to investigate characteristics of water quality and THMs formation in lake-waters at kunsan. Of the parameters examined for water quality, pH, alkalinity, SO$_4$$^{-2}$ and Co- reflected the characteristics according to the origin, geography and water source of lakes while COD, SS, T-P, T-N and chlorophyll-a corelatively reflected well the influence of pollution factors around factors around lakes. The result of water quality analysis showed that most lakes in Kunsan area have the severe eutropnication problem, especially in summer. In lake-waters, THMFP overally continued to increase until 48 hour with the reaction time and THMs formation was largely achieved within 24 hour of the reaction time. The average formation ratio were 68.2% for CHCl$_3$, 23.6% for CHCl$_2$Br, 7.6% for CHClBr$_3$ and 0.6% for CHBr$_3$respectively and much difference depending on the reaction time was not shown. Overally, 96h-THEFP levels in lakes were high during June~September and showed higher tencency in lakes where could be regarded more contaminated on the whole. These results suggest that THMFP may be available for the management of lake-water quality as one if the useful parameters for the general evaluation of contamination. 96h-THEMFP failed to show the strong corelation individually with pH, TOC, COD and chlorphyll-a.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.87-92
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• 2016

With the population growth and industrialization, the characteristics of discharged waste water and sewage have become more diverse. The removal of phosphorus (P) in the wastewater is essential for the prevention of eutrophication in the river and stream. This study was performed in order to estimate the field application of the Bacillus sp. 3434 BRRJ. Bacillus sp. 3434 BRRJ was cultured in the raw wastewater and synthetic medium at the 5 L reactor. The best optimum conditions for P removal by Bacillus sp. 3434BRRJ in the synthetic medium at the 5 L reactor were as follows: temperature, $30^{\circ}C$; P concentration, 20 mg/L; carbon sources, glucose + acetate (1:1); oxygen concentration, alternatively anaerobic and aerobic conditions. P removal efficiency under the optimum condition was 89.4%. In case of wastewater, P removal efficiency was 95.5% under controlled at $30^{\circ}C$. Through this study we confirmed that P removal by Bacillus sp. 3434BRRJ in case of wastewater was as effective as the synthetic medium. It is considered that Bacillus sp. 3434 BRRJ can be applied to the treatment of wastewater in order to biologically remove P from the wastewater on a large scale.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.6
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• pp.521-527
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• 2017

Phosphorus is one of the limiting nutrients for the growth of phytoplankton and algae and is therefore one of leading causes of eutrophication. Most phosphorous in water is present in the form of phosphates. Different technologies have been applied for phosphate removal from wastewater, such as physical, chemical precipitation by using ferric, calcium or aluminum salts, biological, and adsorption. Adsorption is one of efficient method to remove phosphates in wastewater. To find the optimal media for phosphate removal, physical characteristics of media was analysed, and the phosphate removal efficiency of media (silica sand, slag, zeolite, activated carbon) was also investigated in this study. Silica sand showed highest relative density and wear rate, and phosphate removal efficiency. Silica sand removed about 36% of phosphate. To improve the phosphate removal efficiency of silica sand, Fe coating was conducted. Fe coated silica sand showed 3 times higher removal efficiency than non-coated one.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.1
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• pp.49-60
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• 2004

Life Cycle Assessment for the pulp, which is mainly used as the raw material of fine paper, base paper for food packaging and paper cup, has been carried out in this study to consider environmental aspects by quantifying the environmental emission and to evaluate its environmental impact potential. The system boundary was selected from cradle to gate stage(raw material acquisition, transportation of raw material and product manufacturing) of the product. Environmental impact was divided into 8 categories considering Korean situation: abiotic resource depletion, global warming, ozone depletion, acidification, eutrophication, photochemical oxidant creation, ecotoxicity and human toxicity. In Life Cycle Impact Assessment(LCIA) methodology phase, Ecopoint, Eco-indicator 95 and Korean eco-indicator were used and the results carried out by each methodology were compared. The results from this study were also compared with those of foreign study to verify the reliability of the results. The results of the study could be utilized as the basic data for Environmental Management System(EMS), Design for Environment(DfE) and Type III eco-labeling in the paper and paper-related industry.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.558-566
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• 2018

The objective of the study was to determine nutrition regime and limitation in the Boryeng Reservoir where there's a water tunnel between Geum River and the reservoir. Evaluation was conducted through in situ algal bioassay experiments (in situ ABEs) using the cubitainer setting in the reservoirs. For in situ ABEs, we compared and analyzed variations in chlorophyll-a (CHL-a) and phosphorus concentrations in Boryeong Reservoir before and after the water tunnel construction. We then analyzed the nutrient effects on the reservoir. Analysis for nitrogen and phosphorus was done in the three locations of the reservoir and two locations of the ABEs. The in situ ABEs results showed that phosphorous and Nitrogen, the primary limiting nutrient regulating the algal biomass was not limited in the system. The treatments of phosphorus or simultaneous treatments of N+P showed greater algal growth than in the control of nitrate-treatments, indicating a phosphorus deficiency on the phytoplankton growth in the system. The water from the Geum River had 5 times higher total phosphorus (TP) than the water in the reservoir. Efficient management is required as pumping of the river water from Geum River may accelerate the eutrophication of the reservoir.

• Journal of Korean Society on Water Environment
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• v.35 no.1
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• pp.55-63
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• 2019

The Four Major Rivers Restoration Project started in 2009 and completed in early 2013 is a large-scale inter-ministry SOC project investing ₩22.2 $10^{12}$ and one of the Project's objectives was to enhance the water-quality grade through recovering the river eco-system and environment. The average concentration and probability distribution of water-quality constituents at given and selected sampling sites are very significant elements for analyzing and controlling the water-quality of rivers or reservoirs effectively. Average concentration can be estimated by point estimator, distribution function of water-quality constituents or Bootstrap method, in which the distribution function estimated with more data in case of insufficient dataset, is applied. Ipo and Gangcheon water-quality monitoring stations in South Han River were selected to compare and analyze the variation of concentration before and after Ipo and Gangcheon Weirs construction, using the whole 4-year's data, from 2005 to 2008 and from 2014 to 2017. Water-quality constituents such as BOD and COD relating to oxygen demanding wastes and TP and Chlorophyll-a relating to the process of nutrient enrichment called eutrophication were also selected. The guidelines for water-quality control and management after weir construction including evaluation of water-quality constituents' variations can be presented by this paper.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.196-203
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• 2013

Environmental problems like global warming have now become important issues that should be considered in all industries, including construction. In South Korea, many studies have been conducted to achieve the government's goals of reduction in environmental impacts. However, the research on buildings has only focused on CO₂ emission as a research target despite the fact that other environmental impacts resulting from ozone depletion and acidification should also be considered, in addition to global warming. In this regard, this study attempted to propose assessment criteria and methods to evaluate the environmental performance of the structures from various aspects. The environmental impact category can be divided into global impacts, regional impacts, and local impacts. First, global impacts include global warming, ozone layer depletion, and abiotic resource depletion, while regional impacts include acidification, eutrophication, and photochemical oxidation. In addition, noise and vibration occurring in the building construction phase are defined as local impacts. The evaluation methods on the eight environmental impacts will be proposed after analyzing existing studies, and the methods representing each environmental load as monetary value will be presented. The methods presented in this study will present benefits that can be obtained through green buildings with a clear quantitative assessment on structures. Ultimately, it is expected that if the effects of green buildings are clearly presented through the findings of this study, the greening of structures will be actively expanded.

• Journal of Environmental Health Sciences
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• v.44 no.4
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• pp.315-322
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• 2018

Objectives: A lake is a place used by many people, and compared to rivers it is easy for them to become polluted. The water quality in lakes and reservoirs has been worsening recently. The purpose of this study is to evaluate the water pollution characteristics of major lakes in northern Gyeonggi-do Province. Methods: Six lakes were selected as major lakes and were evaluated in terms of water pollution characteristics and eutrophication (as defined by results for $COD_{Mn}$, TOC, SS, Chl-a, T-N and T-P) over one year (from December 2016 through November 2017) in northern Gyeonggi-do Province. Results: The annual average $COD_{Mn}$ was found to be 3.1 mg/L in Onam, 3.6 mg/L in Sanjeong, 4.7 mg/L in Gisan, 4.8 mg/L in Ilsan, and 6.1 mg/L in Jangja. The results of the Korean trophic state index ($TSI_{KO}$ ) value indicated a eutrophic state ($TSI_{KO}$ 59.0) in Jangja lake. The other lakes were classified as being in a mesotrophic state ($TSI_{KO}$ of 38.1 in Sanjeong, 40.2 in Ilsan, 41.9 in Onam, 46.1 in Gisan, and 47.8 in Gomo). Conclusions: Ilsan Lake's water quality is being well maintained. Sanjeong, Onam, and Gisan are appropriate for use as agricultural water. Jangja lake requires efforts for water quality improvement and to prevent the inflow of non-point pollutant sources.

• Journal of Environmental Science International
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• v.4 no.5
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• pp.83-83
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• 1995

The increase of population and industrial activities had brought into eutrophication in the Nakdong river. A remarkable acceleration of eutrophication brought about serious problems for water supply. Therefore, for the purpose of conservation of water quality in the Nakdong river it is necessary to control nutrients. MBOD method was use to evaluate algal growth limiting factor and algal growth potential in the Nakdong river from June to August 1994. The modified biochemical oxygen demand(MBOD) depends on the amount of available inorganic nutrient and organic substrate during 5 day incubation in the dark at 20$^{circ}C$. The MBOD assay depends on inorganic nutrients such as P and N as well as reduced carbon and called the MBOD, the MBOD-P, and the MBOD-N, respectively. The results of bioassay by MBOD(Modified BOD) method showed that the MBOD, MBOD-P and MBOD-N value were found to be in the ranges of 3.8∼96.0 mg$O_2$/l, 5.6∼94.0 mg$O_2$/l and 42.0∼220 mg$O_2$/l, respectively. And the the bioassay value was found to be the highest in Koryong area and the lowest in Waekwan area throughout the Nakdong river. The variations of MBOD-P and MBOD-N value showed similar tendencies to the variations of phosphorus and nitrogen value, respectively. By MBOD method, the relationships of MBOD, MBOD-P and MBOD-N value were MBOD ≒ MBOD-P 《 MBOD-N. The MBOD value was nearly equal to the MBOD-P value, and the MBOD-N value was 3 to 20 times more than the MBOD-P value, approximately. Therefore, in the Nakdong river, phosphorus was the limiting factor for algal growth during summer season. The algal growth potential as the concentration of chlorophyll-a in the summer was maximum 5 times more than standing crop as it.