• Journal of Wetlands Research
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• v.22 no.2
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• pp.130-138
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• 2020

As of 2017, the sewerage penetration rate of Seoul and metropolitan cities is more than 90%, and the number of domestic sewage treatment plants increased by 25% from 3,064 in 2010 to 4,072 in 2017. Among them, sewage treatment plant operated by SBR system is 585, which is 17% higher than 2010. In order to improve the water quality of the water source and improve the operation of the small sewage facilities, the improvement of the process was studied by applying the modelling to 49 facilities of the sewage treatment plant in Andong Imha dam area with more than 500㎥/day 3 places and 46 places less than 500㎥/day. As an improvement plan for modelling, candidate data were derived by reviewing operation data for 5 years. 49 facilities are operated by 12 types of operating processes. Among them, 1 place mort than 500㎥/day with SBR method and 9 facilities with less than 500㎥/day were selected by dividing 46 sites into 3 types. As a result of applying modelling to more than 500㎥/day, it was possible to improve the quality of discharged water through SRT control and it was found that applying model to sites of small scale treatment plants can improve the removal efficiency of TP by up to 14.4%. As a result, the data of this study could be used to improve and improve the operation of sewage treatment plants and RCSTP(Rural Community Sewage Tratment Plant).

• Journal of Korea Water Resources Association
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• v.35 no.5
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• pp.525-539
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• 2002

Effects of Yongdam Dam discharge conditions on water quality of the Keum River and Daechung Lake inflow were analyzed for various scenarios using WASP5 water quality model. Three different groups of scenarios were tested: 1) Two different weather conditions; the lowest flow year and the highest flow year since the beginning of Daechung Dam operation in 1981, 2) Fine discharge flow rates; 5.4, 8.9, 12.4, 16.4 ㎥/s and field observed flow during the study period, 3) Three conditions of discharge water quality; first grade, second grade by Korean water quality standard and field observed water quality. Effect of changes in Yongdam Dam discharges was greater for dry year. The increase of discharge from the Yongdam Dam will improve water quality of downstream areas only when the water quality of the discharge is equal or better than that of downstream areas. Field observed water qualify data show that BOD concentrations are lower than first grade level but TN and TP concentrations are exceeding 5th and 3rd grade level in Korean standard, respectively. Considering that nutrient control methods in watershed areas of Yongdam dam are limited, it is expected that nutrient concentrations from Yongdam Dam discharge will be higher than 2nd grade water quality standard level. Therefore, it would be important to develop practical management strategies in the watershed area of Yongdam Dam based on field conditions for conservation of water quality in downstream areas.

• Journal of Environmental Science International
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• v.24 no.8
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• pp.1045-1053
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• 2015

This study evaluated the effect of water level of water resources on water quality in Ulsan. Two reservoirs, Sayeon Dam and Hoeya Dam, were selected and water quality of chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) were analyzed from 2012 to 2014. And the characteristics of precipitation were also analyzed for 70 years (1945~2014) because runoff of non-point pollutant was strongly affected by precipitation. As a result, water deterioration of Sayeon Dam and Hoeya Dam were affected in accordance with lowering water level. For example, the concentrations of COD and TN was negatively correlated with the water level when the water level of Sayeon Dam was gradually decreased in 2013. The TN concentration was increased to 1.432 mg/L from 0.875 mg/L while the lowest water level of Sayeon Dam was recorded 45 m in 2014. Additionally the concentration of COD and TN was sensitively increased with 0.213 mg/L/m and 0.058 mg/L/m on account of non-point pollutant runoff. It is indicated that hereafter a control of non-point pollutant runoff is the critical factors to maintain water resources because the contribution of non-point pollutant is expected to increase due to the frequent heavy rain events. Therefore, it is necessary to map out a specific plan for non-point pollutant control based on analyses of runoff characteristics, water pollution sources and reduction plans in water pollutants and to establish a water modelling and database system as a preventive action plan.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.10a
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• pp.407-411
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• 2004

Ohmic heating occurs when an electric current is passes through food, resulting in a temperature rise in the product due to the conversion of the electric energy into heat. The time spent in the thawing is critical for product sterility and quality. The objective of this study is to conduct numerical modelling between the effect of ohmic thawing intensity on PTT(phase transition time) at constant concentration and the effect of matrix concentrations on PTT at constant voltage condition. the stronger ohmic thawing intensity resulted in decreasing the PTT. High ohmic intensity causes short PTT. And the higher gelatin concentration, the faster increment of PTT. A numerical modeling was executed to predict the PTT influenced by the power intensity using exponential regression and the PTT influenced by gelatin concentration using logarithmic regression. Therefore, from this numerical model of gelatin matrix, it is possible to estimate exact values extensively.

• Journal of Environmental Science International
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• v.17 no.6
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• pp.611-621
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• 2008

This study intends to provide the necessary basic data needed for predicting the water quality and examining changes in water quality on the basis of the hydrological changes: an outflow or the character of a flow by investigating the interaction of the parameters through the estimation of optimal parameters need for predicting the water quality of the dam basin and the sensitivity among those estimated parameters. Im-Ha Dam in the upstream area of the Nakdong River was selected for analysis, and the water quality survey data necessary for parameter estimation was based on the monthly water quality data (water temperature, BOD, T-N and T-P) between December 1, $2005{\sim}$November 31, 2006. K1C(the saturated growth rate of plant plankton), K1RC (endogenous respiratory quotient of plankton), KDC(deoxidized ratio), K71C(minealized ratio of dissolved organic phosphorus), K83C(mineralized ratio of dissolved organic nitrogen) have been considered as the factors of the water quality performed in this water quality simulation, that is, the most effective parameters on BOD, T-N and T-P. In the result of the analysis of the sensitivity, KDC(deoxidized ratio) was the most sensitively reacted parameter on BOD and it was K71C(mineralized ratio of dissolved organic phosphorus) and K83C(mineralized ratio of dissolved organic nitrogen) on T-N and T-P. It is considered that it will be possible to apply the most optimal parameter to an analysis of the water quality simulation at Im-Ha Ho basin in the goal year by examining the interaction of the parameters through the parameters sampling which are able to applicable to prediction of the water quality and the analysis of the its sensitivity, in the future, also the analysis on the basis of the hydrological conditions: an outflow or the character of a flow will be needed.

• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.587-596
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• 2003

Application of a catchment modelling system requires recorded information to ascertain the reliability and robustness of the predicted flow conditions. Where this recorded information is not available, the necessary information for reliable and robust predictions must be obtained from other available information sources. The alternative approach presented in this paper used inference models for getting this necessary information that is required to calibrate and validate the catchment modelling system for both an ungauged and a gauged catchments. In this study, inference models were developed for determination of control parameters of the Storm Water Management Model (SWMM), mainly based on landuse component of the catchment, which is a major factor to impact on quantity and quality of catchment runoff. Results from the study show that the new approach for determination of the spatially variable control parameters produced more accurate estimates than a traditional approach. Also, the number of control parameters estimated can be reduced significantly as the proposed method only requires determination of control parameters associated with each land use of the catchment while a traditional approach needs to assign a number of control parameters for a number of subcatchment.

• Journal of Korea Water Resources Association
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• v.55 no.spc1
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• pp.1235-1249
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• 2022

This study applied the web crawling technique for extracting big data news on water quality accidents in the water supply system and presented the algorithm in a procedural way to obtain accurate water quality accident news. In addition, in the case of a large-scale water quality accident, development patterns such as accident recognition, accident spread, accident response, and accident resolution appear according to the occurrence of an accident. That is, the analysis of the development of water quality accidents through key keywords and sentiment analysis for each stage was carried out in detail based on case studies, and the meanings were analyzed and derived. The proposed methodology was applied to the larval accident period of Incheon Metropolitan City in 2020 and analyzed. As a result, in a situation where the disclosure of information that directly affects consumers, such as water quality accidents, is restricted, the tone of news articles and media reports about water quality accidents with long-term damage in the event of an accident and the degree of consumer pride clearly change over time. could check This suggests the need to prepare consumer-centered policies to increase consumer positivity, although rapid restoration of facilities is very important for the development of water quality accidents from the supplier's point of view.

• Journal of Soil and Groundwater Environment
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• v.22 no.3
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• pp.1-9
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• 2017

The numerical analysis of groundwater flow is indispensable for predicting problems associated with water resource development, civil works, environmental hazards, and nuclear power plant construction. Korea lacks public regulatory procedures and guidelines for groundwater flow modeling, especially in nuclear facility sites, which makes adequate evaluation difficult. Feasible step-by-step guidelines are also unavailable. Consequently, reports on groundwater flow modeling have low-grade quality and often present controversial opinions. Additionally, without public guidelines, maintaining consistency in reviewing reports and enforcing laws is more challenging. In this study, the guidelines for groundwater flow modeling were reviewed for three countries - the United States (Documenting Groundwater Modeling at Sites Contaminated with Radioactive Substances), Canada (Guidelines for Groundwater Modelling to Assess Impacts of Proposed Natural Resource Development Activities), and Australia (Australian Groundwater Modelling Guidelines), with the aim of developing groundwater flow modeling regulatory guidelines that can be applied to nuclear facilities in Korea, in accordance with the Groundwater Act, Environmental Impact Assessment Act, and the Nuclear Safety Act.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1228-1237
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• 2005

In order to predict the long-term effects of pollutants in sediment on the water quality and the improvement of water quality according to dredging operation, models applied to decide the location and the propriety of dredging were developed. At first, the area was divided into several segments and the developed model was applied to simulate the behaviors of contaminants in an aquatic environment by using estimated parameters. And then through the sensitivity analysis between parameters, the optimum values were determined. The long-term modelling in the area A forecasted that PCBs concentration in the hot spot was decreased from $3.1\;{\mu}g/L$ to $2.4\;{\mu}g/L$ in 30 years. Contaminants in sediment as a source of water pollution did not reduce remarkably in the long run. Therefore it is difficult to expect the improvement of water qualities without the fundamental isolation of contaminants from sediment. It is considered that the selective dredging in the spot improves the water quality consequently.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.1
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• pp.25-35
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• 2015

As livestock manure treatment is becoming a problem, manure application in forest plantation is recommended as an alternative. In this study, to investigate the impact due to liquid manure application in forest plantation, soil, soil water and shallow groundwater quality had been monitored in poplar experimental site where the liquid manure (LM) was applied. Water samples were collected weekly during growing season (April to October) from 2008 to 2011. From the monitoring results, phosphorus concentration in the soil and soil water had no significant difference between LM and control plots. $NO_3$-N concentration of soil water in LM, however, showed higher concentration (13.6 mg/l at 40 cm, 35.1 mg/l at 80 cm) than control plot (1.5 mg/l at 40 cm, 0.5 mg/l at 80 cm). In case of shallow groundwater quality, pH, heavy metal, etc. were satisfied to the national agricultural water quality standard of groundwater and there were no significant difference between upstream and downstream. The $NO_3$-N concentration of shallow groundwater was also not exceeded the national drinking water standard. However, $NO_3$-N concentration in soil water and downstream of shallow groundwater had increased in 2011 when non-composted LM was applied mostly in non-growing season of tree (September). From the results, it is important to control nitrogen source, application time and decomposed or not when LM is applied. In addition, to investigate nitrate source, further long-term monitoring and modelling could be necessary.