• Asian Journal of Turfgrass Science
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• v.17 no.2_3
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• pp.87-97
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• 2003

The growth characteristics of creeping bentgrass seeded in the seaside landfill golf course are as follows. 1. As a result of analysis on the chemical characteristics of soil mixture used for turfgrass ground in this experiment, soil pH was 7.9, which is somewhat higher than the creeping bentgrass reference value of pH 5.5∼6.5; T-N(%) was 0.02, which is proper for the reference value, and trace element too lacked. 2. The cultivar with the fastest water infiltration was Seaside II recorded as 226.2cm/sec, while that with the slowest water infiltration was Pennlinks recorded as 141.1 cm/hr which was too faster than the USGA water infiltration reference value of 15∼30cm/hr. For the surface hardness of turfgrass ground with different cultivars, no statistically significant variation was found between the Penncross grass and the Pennlinks recorded as 18.6mm and 19.1 mm, respectively. The soil penetration was the highest in Pennlinks recorded as 7.6kg/$\textrm{cm}^2$ and lowest in Penn A-1 as 6.1kg/$\textrm{cm}^2$. 3. As a result of evaluation on visual quality at the early stage of growth, Penncross showed the most excellent visual quality compared to the others. However, Penn A-1 showed the most excellent visual quality at a late stage of growth around Sep. 17, 2003, and it was also excellent in the evaluation of visual color. Seaside II showed higher density around the root and the longest root length and was highly resistant to salt compared to others, but the initial sprouting rate was not satisfied, and the visual quality in the summer season was inferior to others. 4. As a result of measurement of the traffic injury, Penncross showed the most tolerant to the traffic stress and Pennlinks showed the most susceptible.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.533-536
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• 2003

The objective of in this study makes investigation into the characteristics of antiwashout underwater concrete as to mix proportion, casting and curing water through experimental researches. in this study, sea sand is blended with river sand, crushed sand is blended with river sand and sea sand as to investigate the quality change and characteristics of antiwashout underwater concrete with variation of blend ratio of sea sand and crushed sand(0, 20, 40, 60, 80, 100%). Higher compressive strength is measured following the order of river sand, sea sand, crushed sand regardless of age and casting condition. Except for case of using river sand, blended ratio of 40% is appeared on most compressive strength.

• Journal of Korean Society on Water Environment
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• v.29 no.2
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• pp.223-231
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• 2013

This study investigated the physio-chemical water quality and the standing crop of the phytoplankton of Dong-stream in Jeollanam-do from May 2010 to Feb 2011. The indicators and the dominant species of phytoplankton were also measured to investigate the water quality of estuary. Nutrients turned out to be eutrophic to hypertrophic in most sites with total nitrogen ranging 1.023~10.743 mg/L and total phosphorous ranging 0.0182~1.6848 mg/L. The site D6 had the highest BOD ranging 0.6~7.5 mg/L. Total of 205 taxa appeared within the research period, Bacillariophyceae being the highest number of taxa. The appeared species were taxa resistant to pollution including Navicula pupula, N. subminuscula, Nitzschia amphibia and N. palea. The downstream is thought to be greatly affected by the ocean water since marine and estuary phytoplankton such as Skeletonema costatum, Coscinodiscus radiatus, Bacteriastrum delicatulum and Eucampia biconcave appeared. Diatom appeared mainly as dominant species including Cymbella minuta, Melosira varians, Gomphonema parvulum, Stephanodiscus hantzschii. As for Stephanodiscus hantzschii, it dominates during fall and winter when the water temperature drops. Diatom showed 50% or higher dominant rate in all seasons at most sites. Most sites turned out to be eutrophic based on the standing crop of cells and chlorophyll a concentration. Total of 15 polluted water indicating taxa including Oscillatoria limosa appeared. From this result, the Dong-stream was considered to be in the eutrophication.

• Journal of the Korean Society for Marine Environment & Energy
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• v.6 no.1
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• pp.68-77
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• 2003

The Water quality of Namdae and Yeongok stream, located in the Kangnung City, and pollutants discharged to the east sea of Korea were investigated during april to November 2002 in order to understand the costal pollution phenomena. The water qualify grade of Namdae stream vary between II and V of water standard. On the other hand, that of Yeongok Stream is keeping I or II. The temporal and spacial variation of Namdae stream are higher than Yeongok stream. The water pollutants discharged to the east sea of Korea from Yeongok stream are lower 15.5 times for BOD, 2.6 times for COD, 1.7 times for T-N, 6.9 times for T-P than from Namdae stream, of which water flux are 1.4 times higher and contain much more of pollutants than Yeongok stream. It may have some effect on the costal ecosystem according to their pollutant flux.

• Journal of Environmental Science International
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• v.28 no.5
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• pp.465-474
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• 2019

Herein, we analyzed the spatial and temporal variation of DO (dissolved oxygen), BOD (biochemical oxygen demand), and COD (Chemical Oxygen Demand) with the monthly mean observed data for 10 years (2008~2017) in the main stream of the Nakdong River. The water quality of the stations declined in a downstream direction, with the BOD and COD showing their highest values at the ST5 station. From the analysis of the correlation of water quality components at 10 stations, the correlation coefficient between the DO and water temperature was more than -0.90, and that between BOD and Chl-a was 0.48~0.85, and that between COD and TOC was more than 0.65 except for the ST5 and ST10 stations. From the regression analysis using data collected from all stations, the water temperature and DO decreased linearly with a coefficient of determination of 0.90, and the Chl-a and BOD could be described by increasing power functions with a coefficient of determination of 0.83. The TOC and COD followed increasing logarithm functions with a coefficient of determination of 0.58. The TOC efficiency at the 10 stations was estimated and the average efficiencies of BOD and COD were 15.5~36.3% and 57.4~89.6%, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.9
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• pp.590-596
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• 2012

Enhanced coagulation is best available technologies to treat NOM in water to produce clean drinking water. In this research, the comparison experiments between conventional coagulation (CC) and enhanced coagulation (EC) using 4 type coagulants i.e., ferric chloride, aluminium sulphate (alum), poly aluminium sulphate organic magnesium (PSOM) and poly aluminium chloride (PACl) were performed in terms of surrogate parameters such as dissolved organic carbon (DOC), trihalomethane formation potential (THMFP), haloacetic acid formation potential (HAAFP) and zeta potential variation in order to find out the most effective coagulant and conditions to fit Nakdong River water. When applied to EC process, the turbidity removal efficiency did not increased gradually compared to the CC process when adding coagulants. Furthermore, the removal efficiency of turbidity became decreased much more as coagulants were added increasingly whereas the removal efficiency of DOC, THMFP and HAAFP became increased by 13~18%, 9~18% and 9~18% respectively compared to the CC process. The characteristics of turbidity removal showed relatively high removal efficiency considering the pH variation in entire pH range when using $FeCl_3$ and PACl. Additionally, in case of alum and PSOM steady removal efficiency was shown between pH 5 and pH 8. In terms of DOC surrogate the coagulants including 4 type coagulants indicated high removal efficiency between pH 5 and pH 7. The removal efficiency of dissolved organic matter (DOM) in EC between less than 1 kDa and more than 10 kDa augmented by 11~21% and 16% respectively compared to the CC process. The removal efficiency of hydrophobic and hydrophilic organic matter proved to be increased by 27~38% and 11~15% respectively. In conclusion, the most effective coagulant relating to EC for Nakdong River water was proved to be $FeCl_3$ followed by PSOM, PAC and alum in order.

• Journal of Environmental Health Sciences
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• v.24 no.1
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• pp.87-97
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• 1998

This study was performed to investigate the Natural mineral water quality at 47 sites in Chonnam area, samples were collected spring, summer, fall, winter for a seasonal variation in 1996. The results obtained were summarized as follows 1. The mean of F, pH, HCO$_3$, NO$_3$ -N were 0.19 mg/l, 6. 9, 34.99 mg/l, 1.40 mg/l and those of Na, K, Ca, Mg were 12.1 mg/l, 1.2 mg/l, 7.7 mg/l, 2.1 mg/l respectively. 2. The contents of F were reasonable at Multonggol as 1.35 mg/l and Yongbayui as 0.57 mg/l respectively, but there is no detected at Sidong and detected below 0.1 mg/l at Gubongsan, Hansansa area. 3. According to the geological effect, the content of F was showed higher in granite than in tuff, and index of pH was higher in tuff than in andesite, and content of HCO$_3$ was higher in andesite than in granite. 4. The K and O values were used as index of healthy and delicious water. As a result, thirtyfive sites(74.5%) was decided as healthy and delicious water. 5. The contents of NO$_3$-N were detected over 5 mg/l at Sukchonsa, Gajanggol, Yudalsan, Muchang, Kisan.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.536-542
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• 2000

The purpose of this study is to evaluate the effect of stream quality by the farmer＇s livestock wastes management in a typical small agricultural watershed. AGNPS model has the capability to adjust the level of pollutant load from farmstead and the fertilization level of upland field. A small agricultural watershed(4.12 $\textrm{km}^2$) which has as livestock farmhouses located in Gosan-myun, Ansung-gun was selected. AGNPS data were prepared by using Arc/info and Idrisi. 4 storm events in 1999 was used for runoff calibration, and 2 storm event which is measured in hourly-base at 4 locations along the stream were used for water quality(TN, TP) calibration. Model＇s behavior to stream quality for 3 cases was investigated. First, the variation of pollution produced from the cattle shed affected little to the stream quality because the cattle sheds were roofed. Second, the good management of ground in farmstead affected to stream quality with 11% and 17% decrease in TN and TP, respectively. Third, the reduction of fertilization level to upland field affected to stream quality with 27.2% and 38.5% decrease in TN and TP, respectively.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.5
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• pp.323-334
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• 2021

Pilot-scale coagulation and sedimentation processes were operated to investigate the T-P (Total phosphorus) removal efficiency. A multiple regression model was also derived to predict the water quality improvement effect with river water characteristics. The inflow rates for the pilot-scale facility were 157-576 m³/day, and the coagulant doses were in the range of 13.7-58.5 mg/L (average 38.9 mg/L) for PAC (Poly alum chloride) and 16.5-62.1 mg/L (average 36.0 mg/L) for alum. The results found that the influent BOD (Biochemical oxygen demand) and T-P concentrations were 4.9 mg/L and 0.115 mg/L, and the removal efficiencies were 52.7% and 59.4%, respectively. T-P removal efficiencies on wet weather days were higher by 10% than dry weather days because influent solids influenced T-P's coagulation process. The pH of river water was 6.9-7.8, and the average pH was 7.3. Although the pH variation was not significant, the trend showed that the treatment efficiency of T-P and PO₄-P removal increased. Thus, the pH range considered in this study seems to be appropriate for the coagulation process, which is essential for phosphorous removal. The T-P removal efficiencies were 19.6-93.3% (average 59.2%) for PAC and 16.4-98.5%(average 55.9%) for alum; thus, both coagulants showed similar results. Furthermore, the average coagulant doses were similar at 42.4 mg/L for PAC and 41.3 mg/L for alum. When the T-P concentration of the effluent was compared by the [Al]/[P] ratio, the phosphorus concentration of the treated water decreased with an increasing [Al]/[P] ratio, and the lowest T-P concentration range appeared at the [Al]/[P] ratio of 10-30. A seasonal multiple regression analysis equations were derived from the relationships between 10 independent and dependent variables (T-P concentration of effluent). This study could help lake water quality maintenance, reduce eutrophication, and improve direction settings for urban planning, especially plans related to developing waterfront cities.

• Journal of Korean Society on Water Environment
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• v.21 no.1
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• pp.52-58
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• 2005

The assessment on characteristics of hydraulic behavior and water quality variations of underground reservoirs of buildings were studied. Firstly, it was thought that underground reservoir capacities($m^3$) of buildings should be not determinated by the uniform and same methods but be estimated on the basis of the dwelling areas on dominated households and their residential characteristics, because these characteristics influence significantly on actual water usages and patterns of buildings. Secondly, it was likely that the average reduction rate of residual chlorine in underground reservoirs were affected from the their capacities, because the average reduction rate of residual chlorine in underground reservoirs under $1,000m^3$ was 43 percent, on the other hand, that rate of underground reservoirs over $1,000m^3$ was 60 percent. Thirdly, through the field investigation, the retention time of drinking water in underground reservoirs were in the range from 0.3 day to 3.9 day. In addition to, the average reduction rate of residual chlorine were depended largely on the retention time of drinking water. When the retention time was under 24 hours, the average reduction rate of residual chlorine was 45 percent, and in case of over 24 hours, was 49 percent. Fourth, water level in underground reservoirs was averagely varied in the range from 0.1 m to 2.65 m at the height of underground reservoirs. If considered actual height of underground reservoirs, 37.6 percent of the height of underground reservoirs was only used. Consequently, the frequency of the inflow and outflow of drinking water in underground reservoir were very increased, and had an effect on the reduction of residual chlorine. Lastly, the investigations on hydraulic structure characteristics of underground reservoirs inside showed the locations of inflow and outflow of drinking water almost were in the opposite direction. And some buildings had several baffles in the middle. Nevertheless, their installations had no beneficial for the improvement of water quality.