• Magazine of the Korean Society of Agricultural Engineers
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• v.43 no.5
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• pp.163-171
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• 2001

Reaeration phenomena, the physical process of absorption of oxygen from atmosphere, is one of the important parameters of dissolved oxygen simulation in streams. This study was aimed at predicting reaeration coefficients in rural small streams, examining the influence of drop structure on reaeration and the seasonal fluctuation of reaeration coefficients. Reaeration coefficients of five streams including four tributaries of Bokha watershed in Gyeonggi Ichon and Onyang stream in Chungnam Onyang were measured. Constant rate injection (CRI) method using propane and Rhodamine-WT as gas and dye tracer was adopted. Reaeration coefficients ranged between 6.16 and 29.16 reciprocal day, higher than those in USGS database. Prediction equation,$k_2=CV^{0.593}$, was regressed from the measured data at 95% confidence level, with an absolute error of 21.2% and a standard error of 4.0 reciprocal days. Reaeration coefficients of experimental reaches with drop structure showed percentile increases of 42.3 to 159.2 compared to those without it, an indication that drop structure plays an important role on stream reaeration. Taking into consideration the seasonal fluctuation of reaeration coefficients, the values measured during September and October were the highest, mainly due to the removal of aquatic plants. by intensive rainfall during summer.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.570-577
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• 2000

In this study, using modified tracer method(Constant Rate Injection, CRI method), reaeration rates were measured in the territories of Bokha stream. In case of Kwanri stream, reaeration rates of a diversion were measured simultaneously. Propane gas and Rhodamine-WT were used as gas and dye tracer, respectively. The experimental results show that reaeration rates of the stream were ranged from 6.16 to 24.52 1/day and those of a diversion in Kwanri stream were ranged from 28.39 to 123.61 1/day. It is resulted that mean velocity of stream is a dominant factor in reaeration process and diversion significantly influence on reareation process.

• Water for future
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• v.21 no.3
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• pp.281-290
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• 1988

As the aeration is one of the most important roles for the purification of polluted water, aquatic aerobic microorganism makes use of aerated dissolved oxygen to decompose the pollutant and purify water. In this study, a reactor was operated in a laboratory to examine the effects of salinity and rainfall on reaeration and then a model was proposed to estimate the reaeration coefficient. From the results of the experiments, the reaeration coefficient, $k_2$($day^{-1}$), can be expressed by $k_2=k_{2f}+3.98667{\times}10^{-2}{\cdot}C+4.88437{\times}10^{-1}{\cdot}r\;where\;k_{2f}$ : the reaeration coefficient in the fresh water at $20{\circ}C,\;(day^{-1})$ C: chloride concentration, ($g/{\ell}$), r:rainfall intensity,(mm/hr) Accordingly, it is concluded that the rate of reaeration is proportional to the chloride concentration and rainfall intensity. Also, it is known that the rainfall intensity contributes to the overall oxygen balance in a body of water more significantly than the salinity.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.547-551
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• 1998

Reaeration coefficient is the physical absorption of oxygen from the atmosphere by water. It is the most important natural means by which a stream replaces the oxygen consumed in the biodegradation of organic wastes, and the rate constant describing this process is the reaeration coefficient, It. Reaeration coefficient is the dominant parameter affecting the use of water quality model. Therefore accurate estimation of the reaeration coefficient is essential for optimum water quality management. There is several method to estimate stream reaeration coefficient. In this study, it would be concluded that SI-peak method is of practical use when applied to small stream, and CRI method is adequate to large stream.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.6
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• pp.428-433
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• 2009

Dissolved oxygen is considered as one of the important water-quality constituents in streams from one century ago and fishes perish in low dissolved oxygen concentration. Environmental scientists and engineers have introduced the deterministic model to estimate dissolved oxygen concentration of streams and recommended the use of the Delta Method (DM), Approximate Delta Method (ADM), Extreme Value Method (EVM) and Optimization Method (OPT) which can be applied in no spatial variation of dissolved oxygen. The diurnal or annual variation of dissolved oxygen is mainly determined from the parameters such as reaeration rate, 1st production rate and respiration rate which are related to dissolved oxygen. Each method was briefly introduced and applied to two sampling sites of Anseong Stream watershed in this paper. The limitation, advantages and disadvantages of each method were reviewed and analyzed after running the each method. From these analyses, the benefit-cost approach to estimate dissolved oxygen effectively in streams was recommended.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.595-601
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• 2005

In this research, effects of water circulation on phosphorus release from sediment into water body were studied. Sediments sampled at the Daechung Lake were used for the column experiments with circulation and non-circulation conditions. Deaeration coefficient, $K_1$ and reaeration coefficient, $K_2$ of non-circulation condition were 0.133 and 0, respectively, while $K_1$ and $K_2$ for circulation condition were 0.46 and 0.018, respectively. Oxidation Reduction Potential (ORP) showed a linear relationship with dissolved oxygen (DO) when DO is over 2 mg/L. Phosphorus concentration induced by phosphorus release from sediment was highly dependent upon DO, ORP, and pH. Under anaerobic condition, phosphorus release rate was higher for $Fe^{2+}$-bounded phosphorus compared to that of $Ca^{2+}$-bounded phosphorus.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.3
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• pp.198-207
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• 1990

Among the biodegradable liquid waste treatment and disposal methods, ocean dumping is a cost-effective and productive manner considering reuse point of view However, when biodegradable liquid waste is dumped in the ocean, oxygen consumption by the decomposition of organic matter must be considered. The purpose of this study is to determine the maximum allowable concentration and dumping rate in the southern waters of the East Sea based on dissolved oxygen level. Streeter and Phelps' model has been used to determine the maximum allowable concentration. Factors in this model, deoxygenation constants and reaeration coefficients, have been determined by appling oxygen consumption method and closed system model. Deoxygenation constants and reaeration coefficients from surface to each standard depth are $0.24\~0.29/day\;and\;0.03\~0.39/day$ in summer, $0.17\~0.20/day\;and\;0.04\~0.56/day$ in winter, respectively. The allowable organic matter concentration($mgBOD/\iota$) to the dissolved oxy-gen sag value of $5mg/{\iota}$ is represented $17.23\times(H)^{-0.37}$ in summer, and $64.96\times(H)^{-0.52}$ in winter by mixing depth(H, m). Csanady's experiment has been applied to estimate the optimum dumping rate. The optimum dumping rate($R,\;m^3/sec$) can be written as a product of the beam(b, m) and the draft(h, m) of vessel, and biochemical oxygen demand of waste($L_n,\;mg/{\iota}$) $R=275{\times}bh^{0.63}L_n^{-1}$ in summer $=745{\times}bh^{0.48}L_n^{-1}$ in winter. The difference of dumping rate between in summer and winter is due to the oxygen distribution.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.331-339
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• 2006

This research was carried out to understand the impacts of thickness of sand capping to control phosphorus release from sediment into overlying water. As capping effectively retards release flux, phosphorus concentration in water body can be maintained if phosphorus release rate was kept under microbial degradation rate. With capping thickness increases, deaeration rate become less, while reaeration coefficient become higher. Phosphorus release rate and capping thickness were linearly correlated. The results of regression analysis indicated that phosphorus release can be controlled effectively by sand capping of least 20${\sim}$40 mm thickness.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.179-182
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• 2002

The objective of this study was to evaluate petroleum hydrocarbon degradation processes governing natural attenuation at tile contaminated site and accomplished through conducting on investigation of degradation rate, capacity, and mechanism of the monitored natural attenuation. The monitoring results of the three years indicated that the concentrations of DO, nitrate, and sulfate in the contaminated area were significantly lower than these in the none-contaminated area. The results also showed a higher ferrous iron concentration, a lower redox potential and a neutral pH in the contaminated groundwater, suggesting that biodegradation of TEX is the major on-going process in the contaminated area. However, reduction of TEX in the groundwater was not only biodegradation but also dilution and reaeration during infiltration of uncotaminated surface and groudwater.

• Proceedings of the Korea Water Resources Association Conference
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• 1987.07a
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• pp.159-168
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• 1987

Temporal and spatial prediction of water quality provides the necessary information to a profect planning, design, and model optimization for water quality mangement in a river system. In thes study, the QUAL II model is applied to the Keum River system from the downstream of Dae-Chong dam to the Great Pak-Je bridge. The advection-dispersion model of water quality based on the material balance and the numerical solution method of the model are presented. The enhancement of the model application is empha sized by comparing the observed and the simulated values of BOD, DO, and water temperature. Through these processes, the water quality states of the Keum River system are evaluated and the deoxignation rate, the reaeration rate, and Fair value are estimated. Also, the maintance of the target DO level with the control of the discharge from Dae-Chong dam is discussed.