박진환 Jin Hwan Park , 문명진 Myung Jin Moon , 이형진 Hyung Jin Lee , 김갑순 Kap Soon Kim

DOI:10.15681/KSWE.2014.30.2.119 Vol.30(No.2) 119-127, 2014

The objective of this study is to evaluate and analyze Sumjin River Basin water environment system. It was necessary to improve the water quality. The data were collected from 2010 January to 2012 December including Water Temperature, pH, DO, EC, BOD5, COD, TOC, SS, T-N, T-P. The data were used to study were required to; Correlation Analysis; Principle Component Analysis; Factor Analysis. The results were as followed. According to correlation analysis on BOD5 against COD, TOC it revealed that the each value of correlation coefficient were 0.715 and 0.719; this means the strength of the relationship is strong. The same analysis on T-P against BOD5, COD, TOC, SS has revealed that the range of the correlation coefficient value fell between 0.482 and 0.608 which means strength of the relationship between them remained normal. Through correlation analysis, it has been found that all elements except T-N have high correlation. The results of principal component analysis to target the overall water quality was extracted to three main components. The cumulative contribution rate is 68.990%. In the case of seasonal water quality, Spring and Summer are extracted to each of four main components. The cumulative contribution rate is 81.515% and 73.550% respectively. Fall and Winter are extracted to each of three main components. The cumulative contribution rate is 65.072% and 72.721% respectively. There is no seasonality in the case of factor analysis. The first common factor is BOD5, COD, TOC, SS, T-P, which were classified. Totally speaking, Sumjin River Basin water system gets highly affected by the nutrient salts, organic matter and suspended solid at the same time.

Factor analysis, Principle component analysis, Sumjin river basin, Water quality

박준대 Jun Dae Park , 오승영 Seung Young Oh , 최옥연 Ok Youn Choi

DOI:10.15681/KSWE.2014.30.2.128 Vol.30(No.2) 128-137, 2014

The land use of the unit watersheds should be maintained appropriately in order to keep the load allotment stable for the management of Total Maximum Daily Loads (TMDLs). This study classified the land area in four types and analyzed the use of each land type and its changing pattern by calculating the occupation and conversion ratios for the unit watersheds in three river basins. The forest land showed the greatest occupation ratio with 63.0%, followed by the farm land with 23%, the other area with 8.0% and the site area with 6.0% in 2003. The occupation ratio of the site and the other area increased by 0.4% and 0.2% respectively, and that of the farm and the forest land decreased by 0.4% and 0.2% respectively in 2007. The conversion ratio for the site area ranged from 1.65% to 1.97%, for the farm land from -0.47% to -0.33%, for the forest land from -0.10% to -0.04% and for the other area from 0.17% to 1.97%. It can be inferred that the decrease in the farm and the forest land contributed to the increase in the site area and that the increase in the other area was mainly made by the decrease in the forest land. It could be more effective to take into account the changes in the site area and in the forest land in the process of developing the TMDL plans.

Conversion ratio, Land use pattern, Occupation ratio, Total maximum daily loads, Unit watershed

안정민 Jung Min Ahn , 임태효 Toe Hyo Im , 이인정 In Jung Lee , 이경락 Kyung Lak Lee , 정강영 Kang Young Jung , 이재운 Jae Woon Lee , 천세억 Se Uk Cheon , 박인혁 In Hyeok Park

DOI:10.15681/KSWE.2014.30.2.138 Vol.30(No.2) 138-147, 2014

In order to determine the best operating rules for the Nakdong River, three cases were applied to analyze the simulated results of water supply capacity by HEC-ResSim model. This study discussed to present the best operating rules for conjunctive operating of existing the dams and new constructed the weirs through system network. The system network was constructed considering the water supply, the river environment and the operating facility. The water supply capacities are separately evaluated for each case applying the best rules. It is case1 that the dams are operated individually, case2 that the dams are operated in conjunction with the others dams, and case3 that dams and weirs are operated in conjunction with the others dams-weirs. Comparing the cases, case 3 has shown the best water supply capacity of the Nakdong River.

Conjunctive operation, HEC-ResSim, Nakdong river, Water supply capacity

김은정 Eun Jung Kim , 김용석 Yong Seok Kim , 류덕희 Doug Hee Rhew , 류지철 Ji Chul Ryu , 박배경 Bae Kyung Park

DOI:10.15681/KSWE.2014.30.2.148 Vol.30(No.2) 148-158, 2014

In order to assess the effect of TMDLs management and improve that in the future, it is necessary to analyze long-term changes in water quality during management period. Therefore, long term trend analysis of BOD was performed on thirty monitoring stations in Geum River TMDL unit watersheds. Nonparametric trend analysis method was used for analysis as the water quality data are generally not in normal distribution. The monthly median values of BOD during 2004∼. 2010 were analyzed by Seasonal Mann-Kendall test and LOWESS(LOcally WEighted Scatter plot Smoother). And the effect of Total Maximum Daily Loads(TMDLs) management on water quality changes at each unit watershed was analyzed with the result of trend analysis. The Seasonal Mann-Kendall test results showed that BOD concentrations had the downward trend at 10 unit watersheds, upward trend at 4 unit watersheds and no significant trend at 16 unit watersheds. And the LOWESS analysis showed that BOD concentration began to decrease after mid-2009 at almost all of unit watersheds having no trend in implementation plan watershed. It was estimated that TMDLs improved water quality in Geum River water system and the improvement of water quality was made mainly in implementation plan unit watershed and tributaries.

Geum river, LOWESS, Nonparametric trend analysis, Seasonal Mann-Kendall test, TMDLs

박윤식 Youn Shik Park , 현근우 Geun Woo Hyun

DOI:10.15681/KSWE.2014.30.2.159 Vol.30(No.2) 159-165, 2014

Vegetative Filter Strip (VFS) is one of effective Best Management Practices (BMPs) to prevent sediment-laden water problem, is installed at the edge of source area such agricultural area so that sediment occurred in source area is trapped by VFS before it flow into stream or river. Appropriate scale of it needs to be simulated before it is installed, considering various field conditions. In this study, a model using VFSMOD-w model and Genetic Algorithm to determine effective VFS length was developed, it is available to calibrate input parameter related to source area sediment yield through thousands of VFSMOD-w simulations. Useful DBs, moreover, are stored in the model so that very specific input parameters can be used with reasonable values. Compared simulated values to observed data values for calibration, R2 and Nash-Stucliffe model efficiency coefficient were 0.74 and 0.65 in flow comparison, and 0.89 and 0.79 in sediment comparison. The model determined 1.0 m of Filter Length, 0.18 of Filter Slope, and 0.2 cm of Filter Media Spacing to reduce 80% of sediment by VFS. The model has not only Auto-Calibration module also DBs for specific input parameters, thus, the model is expected to be used for effective VFS scale.

Best management practices, Genetic algorithm, Sediment reduction, Vegetative filter strip, VFSMOD-w

전항배 Hang Bae Jun , 전동걸 Dong Jie Tian , 홍기원 Ki Won Hong , 한홍식 Hong Sig Han , 박병창 Byeong Chang Park

DOI:10.15681/KSWE.2014.30.2.166 Vol.30(No.2) 166-174, 2014

Velocity gradient, G, a measure of the average velocity gradient in the fluid has been applied for complete mixing of chemicals in mechanical mixing devices. G values were calculated by the power input transferred to fluid in turbulent and transient range. Chemical reactions occur so fast that total mass transfer time required for even distribution of the chemicals determine the overall reaction time. The total mass transfer time is composed of the time for complete mixing through the reactor and for diffusion of the chemicals into the eddy. Complete mixing time was calculated by CFD (computer fluid dynamics) and evaluated by tracer tests in 2 liter jars at different rotating speeds. Turbulent range, Reynolds number above 10,000 in regular 2 liter jars occurred at revolution speed above 100 rpm (revolution per minute), while laminar range occurred at revolution speed below 10 rpm. A typical range of rotating speed used in jar tests for water and wastewater treatment was between 10 and 300 rpm, which covered both transient and turbulent range. G values supplied from a commercial jar test apparatus showed big difference from those calculated with power number specially in turbulent range. Diffusion time through eddy decreased 1.5 power-law of rotating speed. Complete mixing time determined by pumping number decreased increases in rotating speed. Total mass transfer time, finally, decreases as rotating speed increases, and it becomes 1 sec at rotating speed of 1,000 rpm. Complete mixing times evaluated from tracer tests showed higher than those calculated by power number at higher rotating speed. Complete mixing times, however, calculated by CFD showed similar to those of experimentally evaluated ones.

CFD, Complete mixing time, Diffusion time, G value, Mass transfer time, Velocity gradient

김선혜 Sun Hye Kim , 김은지 Eun Zi Kim , 김동수 Dong Su Kim

DOI:10.15681/KSWE.2014.30.2.175 Vol.30(No.2) 175-183, 2014

The influence of temperature on the treatment efficiency of chlorinated organic substances contained in groundwater by permeable reactive barrier which is composed of Feo has been investigated by constructing the Pourbaix diagrams for Fe-H2O system at different temperatures based on thermodynamic estimation. In aerobic condition, the equilibrium potentials for Feo/Fe2+ and Fe2+/Fe3+ were observed to increase, therefore, the dechlorination reaction for organic pollutants by Feo was considered to decline with temperature due to the diminished oxidation of reactive barrier. The result for the variations of the ionization fraction of Fe2+ and Fe3+ ion in the pH range of 0 ~ 2.5 obtained by employing Visual MINTEQ program showed that the ionization fraction of Fe2+ increased with pH, however, that of Fe3+ decreased symmetrically and the extent of the variation of ionization fraction for both ions was raised as temperature rises. The equilibrium pH for Fe3+/Fe(OH)3 was examined to decrease with temperature so that the treatment efficiency of chlorinated organic substance was expected to decrease with temperature due to the enhanced formation of passivating film in aerobic condition. The change of the reactivity of a specific chemical species with temperature was defined quantitatively based on the area of its stable region in Pourbaix diagram and depending on this the reactivity of Fe3+ was shown to decrease with temperature, however, that of Fe(OH)3 was decreased monotonously as temperature is raised for Fe3+/Fe(OH)3 equilibrium system. In anaerobic condition, the equilibrium potential for Feo/Fe2+ was observed to rise and the equilibrium pH for Fe2+/Fe(OH)2 were examined to decrease as temperature increases, therefore, similar to that for aerobic condition the efficiency of the dechlorination reaction for organic substances was considered to be diminished when temperature rises because of the reduced oxidation of Feo and increased formation of Fe(OH)2 passivating film.

Chlorinated organic substance, Groundwater, Permeable reactive barrier, Pourbaix diagram, Temperature

박민혜 Min Hye Park , 조홍래 Hong Lae Cho , 구본경 Bhon Kyoung Koo

DOI:10.15681/KSWE.2014.30.2.184 Vol.30(No.2) 184-198, 2014

For estimating discharge and pollution loads into the Yeongsan lake, a conceptual watershed model HSPF(Hydrological Simulation Program - Fortran) was applied to the Yeongsan River Basin. Various spatial data set including DEM, watershed boundaries and land uses were used to set up the model for the Yeongsan River Basin that was divided into 45 sub-basins. The model was calibrated and validated for the river discharges, SS, BOD, TN and TP concentrations against the data observed in 2011 at several monitoring stations. The simulation results show good agreement with the observed water flows(R2 = 0.46 - 0.97, NSE = 0.70 - 0.96). The simulated concentrations of SS, BOD, TN and TP are also in good agreement with the observed. The total freshwater discharge to the Yeongsan lake is estimated 2,406 × 106 m3/year which the Jiseok and Hwangryoung stream contribute as much as 19%, 17% respectively. It is estimated that the total discharges to the Youngsan lake is SS 152,327 ton/year, BOD 15,721 ton/year, TN 10,071 ton/year, TP 563 ton/year. Both water and pollution loads are high in summer, particularly in July, when the monsoon season arrives at the Korean peninsula.

Discharge characteristics, Pollution loads, Watershed model HSPF, Yeongsan river basin

허유정 Yu Jeong Huh , 양미희 Mi Hee Yang , 조양석 Yang Seok Cho , 안경희 Kyung Hee Ahn , 이연희 Youn Hee Lee , 정현미 Hyun Mee Chung , 권오상 Oh Sang Kwon , 박주현 Ju Hyun Park

DOI:10.15681/KSWE.2014.30.2.199 Vol.30(No.2) 199-205, 2014

The knowledge on the migration of antimony (Sb) from PET bottles into the water is of greate concern. Antimony in all bottled water marketed in korea and in raw water was analyzed. The detection rate of antimony in total bottled water was 88 % and 100% in PET (Polyethylene terephthalate, PET), 55% in PC (Polycarbonate, PC) bottled water. 55% of raw water contained antimony. The average concentration of Sb in PET bottled water was 0.39 μg/L, higher than PC bottles (0.20 μg/L) and the raw water (0.22 μg/L). The migration of Sb into water that is stored in different conditions (room temperature, 45℃, and direct sunlight exposure) was investigated for 180 days. The migration tendency increased with the storage time and temperature. PET bottles showed a sharp increase of Sb concentration at 45℃, but there was no differences between the room temperature and sunlight exposure. The Sb migration in all simulated solution(deionized water, 4% acetic acid, and 20% ethanol) also increased with storage time and temperature. The Sb migration values ranged from 0.35 to 0.49 μg/L in all simulated solution, which was far below the permissible korean migration level of 40 μg/L. There was a tendency that the number of re-use of a bottle and the amount of leaching were in inverse proportion.

Antimony, Migration, Natural mineral water, PET bottle, Simulated solution

김선옥 Sung Ok Kim , 김학성 Hag Seong Kim

DOI:10.15681/KSWE.2014.30.2.206 Vol.30(No.2) 206-211, 2014

This study was done to find chemicals adequate to control alkalinity and hardness in order to reduce dissolved phosphorus in water bodies like rivers and lakes. Five chemicals were selected for the study: calcite, lime, dolomite, magnesite, and gypsum. Data were obtained from the calculations with MINTEQ model as a function of dosage variations of each chemical. Findings are as follows: Three out of the five chemicals are found to be effective in reducing the dissolved phosphorus, i.e., calcite, lime, and dolomite. Calcite and dolomite are able to lower the phosphorus concentration up to one thousandth fold whereas lime does one hundred thousandths fold. In viewpoint of pH variation, both calcite and dolomite seem to be safe since the pH does not increase over 8.3 even in case of overdose. In the same circumstance, with lime the pH increases beyond 9 which is considered to be the highest pH level for the protection of water ecosystem. Nevertheless it is recommendable to use lime in case where there are some difficulties in water quality control due to algae blooms.

Alkalinity, Calcite, Dissolved phosphorus, Dolomite, Hardness, Lime

류지철 Ji Chul Ryu , 박윤식 Yoon Sik Park , 한미덕 Mi Deok Han , 안기홍 Ki Hong Ahn , 금동혁 Dong Hyuk Kum , 임경재 Kyoung Jae Lim , 박배경 Bae Kyung Park

DOI:10.15681/KSWE.2014.30.2.212 Vol.30(No.2) 212-219, 2014

In this study, a land pollutant load calculation method in TMDLs was improved to consider climate change scenarios. In order to evaluate the new method, future change in rainfall patterns was predicted by using SRES A1B climate change scenarios and then post-processing methods such as change factor (CF) and quantile mapping (QM) were applied to correct the bias between the predicted and the observed rainfall patterns. Also, future land pollutant loads were estimated by using both the bias corrected rainfall patterns and the enhanced method. For the results of bias correction, both methods (CF and QM) predicted the temporal trend of the past rainfall patterns and QM method showed future daily average precipitation in the range of 1.1~7.5 mm and CF showed it in the range of 1.3~6.8 mm from 2014 to 2100. Also, in the result of the estimation of future land pollutant loads using the enhanced method (2020, 2040, 2100), TN loads were in the range of 4316.6~6138.6 kg/day and TP loads were in the range of 457.0~716.5 kg/day. However, each result of TN and TP loads in 2020, 2040, 2100 was the same with the original method. The enhanced method in this study will be useful to predict land pollutant loads under the influence of climate change because it can reflect future change in rainfall patterns. Also, it is expected that the results of this study are used as a base data of TMDLs in case of applying for climate change scenarios.

CF, Climate change, JinwiA, Land pollutant load, QM, TMDLs

안조환 Jo Hwan Ahn , 배우근 Woo Keun Bae

DOI:10.15681/KSWE.2014.30.2.220 Vol.30(No.2) 220-225, 2014

A sequencing batch reactor (SBR) was operated to obtain thiosulfate-utilizing denitrifier cultivated with two types of electron accepter (nitrate and nitrite). Using the microbial biomass obtained from the SBR, batch tests were conducted with different nitrite concentrations (50 and 100 mg-N/L) at pH 7.0, 7.5 and 7.9 to see how free nitrous acid (FNA) negatively works on the thiosulfate-utilizing denitrification of nitrate. The specific denitrification rate (SDR) of nitrate was significantly influenced by pH and FNA. The presence of nitrite caused a remarked decrease of the SDR under low pH conditions, because of the microbiological inhibitory effect of FNA. The minimum SDR was observed when initial nitrite concentration was 100 mg-N/L at pH 7.0. Moreover. the SDR was influenced by the type of electron acceptor used during the SBR operation. Thiosulfateutilizing denitrifier cultivated with nitrite showed smaller SDR on the thiosulfate-utilizing denitrification of nitrate than those cultivated with nitrate.

Free nitrous acid, FNA, Nitrate, Nitrite, Specific denitrification rate, SDR, Thiosulfate-utilizing denitrification

이철용 Chol Young Lee , 김계현 Kye Hyun Kim , 박용길 Yong Gil Park , 이혁 Hyuk Lee

DOI:10.15681/KSWE.2014.30.2.226 Vol.30(No.2) 226-241, 2014

This study proposes schemes of GIS-based system development for integrated information management in water environment linked with Korean Reach File (KRF). For this purpose, precedent studies and systems of the U.S. were investigated and analyzed to induce optimal methodology for Korean circumstances. Thereafter, data linkage methods of KRF and Water Environment Information System (WEIS), system configuration plans, application development plans, and KRF improvement and maintenance plans were considered. For data linkage and system configuration, three methods were suggested: an overlay operation-based data linkage method, entering spatial addresses into the existing DB, and creating link information between KRF and the existing DB. The first method was predicted to be the most effective for system implementation, the second method is advantageous for search tasks, and the third method is advantageous for system security and maintenance. Various types of applications should be developed in the consideration of the types of the users and their usages. Moreover, there is a need for further research on regular renewal of KRF, standard development, expansion of construction areas, etc. Based on the present results, research on actual system design and development also should be conducted for supporting Total Maximum Daily Loads (TMDLs).

Geographic Information System, GIS, Korean Reach File, KRF, Total Maximum Daily Loads, TMDLs, Water Environment Information System, WEIS