정동일

DOI: Vol.27(No.3) 5-5, 2011

신지웅 Ji Woong Shin , 길경익 Kyung Ik Gil

DOI: Vol.27(No.3) 257-263, 2011

This study analyzes the correlations between non-point sources and runoff to estimate non-point sources for effective management. From the monitoring results, the correlation factors among pollutant mass loading, EMC, total runoff volume and average flow are calculated. And using correlation factors, the most related two constituents are determined. Also the most appropriate regression between two constituents are determined. Pollutant mass loading and total runoff volume has the highest correlation. Also, compound regression is found to be the most appropriate regression. This shows that pollutant mass loading increases as total runoff volume increases. It is not continuous increase but has some pattern.

Correlation, Non-point sources, Regression, Runoff

안정민 Jung Min Ahn , 이상진 Sang Jin Lee , 김정곤 Jeong Kon Kim , 김주철 Joo Cheol Kim , 맹승진 Seung Jin Maeng , 우동현 Dong Hyeon Woo

DOI: Vol.27(No.3) 264-272, 2011

The objective of this study was to develop a model for predicting long-term runoff in a basin using the ensemble streamflow prediction (ESP) technique and review its reliability. To achieve the objective, this study improved not only the ESP technique based on the ensemble scenario analysis of historical rainfall data but also conventional ESP techniques used in conjunction with qualitative climate forecasting information, and analyzed and assessed their improvement effects. The model was applied to the Geum River basin. To undertake runoff forecasting, this study tried three cases (case 1: Climate Outlook+ESP, case 2: ESP probability through monthly measured discharge, case 3: Season ESP probability of case 2) according to techniques used to calculate ESP probabilities. As a result, the mean absolute error of runoff forecasts for case 1 proposed by this study was calculated as 295.8 MCM. This suggests that case 1 showed higher reliability in runoff forecasting than case 2 (324 MCM) and case 3 (473.1 MCM). In a discrepancy-ratio accuracy analysis, the Climate Outlook +ESP technique displayed 50.0%. This suggests that runoff forecasting using the Climate Outlook +ESP technique with the lowest absolute error was more reliable than other two cases.

Climate outlook, ESP, Runoff, Runoff forecast, SSARR

이아연 A Yeon Lee , 김상단 Sang Dan Kim

DOI: Vol.27(No.3) 273-285, 2011

This study describes the modeling of climate change impact on runoff across southeast Korea using a conceptual rainfall-runoff model TANK and assesses the results using the concept of environmental flows developed by International Water Management Institute. The future climate time series is obtained by scaling the historical series, informed by 4 global climate models and 3 greenhouse gas emission scenarios, to reflect a 4.0˚C increase at most in average surface air temperature and 31.7% increase at most in annual precipitation, using the spatio-temporal changing factor method that considers changes in the future mean seasonal rainfall and potential evapotranspiration as well as in the daily rainfall distribution. Although the simulation results from different global circulation models and greenhouse emission scenarios indicate different responses in flows to the climate change, the majority of the modeling results show that there will be more runoff in southeast Korea in the future. However, there is substantial uncertainty, with the results ranging from a 5.82% decrease to a 48.15% increase in the mean annual runoff averaged across the study area according to the corresponding climate change scenarios. We then assess the hydrologic perturbations based on the comparison between present and future flow duration curves suggested by IMWI. As a result, the effect of hydrologic perturbation on aquatic ecosystems may be significant at several locations of the Nakdong river main stream in dry season.

Climate change, Environmental flow, Flow duration curves, Tank model

임지열 Ji Yeol Im , 길경익 Kyung Ik Gil

DOI: Vol.27(No.3) 286-292, 2011

Preparing for the Standards for Effluents which will be strengthen from 2012, many ways like remodellings and repairs of sewage treatment plant (STP) are considered. The treatment of the recycle water from the sludge treatment process contains high-strength organic compounds and nitrogen is considered as alternative. In the treatment of high-strength nitrogen, nitritation has more economic advantages than nitrification. In this study, lab-scale reactor was operated at the 35˚C, 20˚C and 10˚C conditions using effluent of anaerobic digester to investigate the nitrogen removal by nitritation. Long-term stable nitritation was achieved at the 35˚C, 20˚C but 10˚C. In the stable nitritation states, nitrite conversion was higher at the high temperature of 35˚C than the room temperature of 20˚C. Also shorter solid retention time (SRT) was needed to induce high nitrite conversion at the high temperature of 35˚C. It was showed that temperature and SRT are important factors to induce nitritation.

Nitritation, Nitrite, Temperature, Wastewater

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

DOI: Vol.27(No.3) 293-299, 2011

The quantity of a discharge load can change with changes in rainfall in the area with a combined sewer system (CSS). To evaluate the implementation appropriately in the management of total maximum daily loads (TMDLs), the effects of rainfall changes should be considered in the estimation of the discharge load. The rainfall condition for the estimation of the discharge load in a certain year should be standardized to the same rainfall condition as that of the reference year. However, the calculation process is very complicated with its potential limitations. This study investigated and developed relatively simple methods for estimating the discharge load. Load conversion method (LCM) is designed to convert the discharge load under the current rainfall condition into that of the reference rainfall conditions. Simple rainfall data method (SRDM) is to simplify the estimation process of the discharge load by the simple conversion of rainfall data. These methods were applied to calculate the discharge load and examine the estimation results. From the results of this study the application of these methods may be useful for estimating the discharge load in the TMDL process.

Combined sewer system, Discharge Load, Evaluation, Load estimation, Rainfall changes

박종석 Jong Seok Park , 심춘석 Chun Seok Sim , 문병석 Byoung Seok Moon

DOI: Vol.27(No.3) 300-305, 2011

This study aimed at analyzing the runoff quality by the layer thickness and material of soil roof to make best use of the rainwater falling on it in terms of safety and efficiency and resulted in the following assessments. It turned out that the concentrations decreased more in T-N, NO3-N, NH4-N, T-P and PO4-P in roof rainwater except 30 cm for the RW1 soil roof after passing through it than those of first rainwater. On the other hand, the concentrations in rainwater passing through gravel roof turned out to be equal or same to those of the first rainwater. As a result of analysis of metallic stuff in runoff, there was no indication of Cd, Cr, Mn and Pb as well. The concentration of Cu, Fe and Zn in rainwater through soil roof became less than that of the first rainwater. In this research, the soil roof showed the good efficiency in lowering the concentration of such components as nitrogen, phosphorus and metals. Based on the results from this work, more practical study would be required further in the future in relation to soil roof when installing the rainwater-utilizing facilities.

Gravel roofs, Rainwater, Runoff quality, Soil roofs

길경익 Kyung Ik Gil , 김태원 Tae Won Kim , 정명숙 Myung Sook Jung

DOI: Vol.27(No.3) 306-313, 2011

In this paper, runoff characteristics of South-Han river watershed in terms of refractory organic matters were investigated. The concentrations of DOC, POC, R-DOC, R-POC in runoff and flow rates were determined by monitoring 27 times in dry season and 4 times in rainy season. The concentrations of the dissolved refractory organic matter, R-DOC was the lowest in fall and similar in the other dry seasons. The particulate refractory organic matter, R-POC showed less fluctuation than R-DOC. In summer, mass loading was the highest than other dry seasons. The concentrations of R-DOC, R-POC were showed to be affected by runoff volume. The mass loading grows higher as runoff volume gets higher.

Dry season, Organic matters, Rain events, Refractory organic matters

정남일 Nam Il Chung , 박배경 Bae Kyung Park , 김경현 Kyung Hyun Kim

DOI: Vol.27(No.3) 314-321, 2011

The potential effects of increased water temperature on fish assemblages and their habitats were studied in the streams of the Han River watershed when the water temperature was supposed to increase by 1˚C, 2˚C, and 3˚C in each sampling site. The percent changes in suitable habitats for each species and in species number within a site were determined, based on the estimated maximum thermal tolerances of 51 fish species whose habitats were classified into four reaches: upstream, up-/midstream, midstream, and mid-/downstream. The maximum thermal tolerance ranged between 25.0˚C and 31.0˚C and significantly increased as the habitat reaches move from upstream to mid-/downstream. With the increases in water temperature, the average suitable habitats for all 51 species were decreased by 31% (+1˚C), 46% (+2˚C), and 60% (+3˚C). The increased water temperature, however, did not induce significant differences in the changes in suitable habitats among four reaches within each level of temperature increase. The relative frequencies of the sampling sites classified into six levels according to the percent change in the number of species in each site were significantly different among three levels of water temperature increase, with relatively greater changes in the sites where 0~20% and 61~100% of species were affected.

Fish assemblage change, Han River watershed, Maximum thermal tolerance, Suitable habitat, Water temperature increase

박종부 Jong Bu Park , 신경숙 Kyung Sook Shin , 허형우 Hyung Woo Hur , 강호 Ho Kang

DOI: Vol.27(No.3) 322-328, 2011

This study was performed to investigate the characteristics of nutrient removal of municipal wastewater in the membrane bioreactor system with the different types of membrane. Membrane bioreactor consists of three reactors such as two intermittent anaerobic and the submerged membrane aerobic reactor with flat sheet and hollow fiber membrane, respectively. The removal efficiencies of COD(Cr), BOD, SS, TN and TP on the flat sheet membrane bioreactor were 94.3%, 99.0%, 99.9%, 70.3% and 63.1%, respectively. In addition, The removal efficiencies of COD(Cr), BOD, SS, TN and TP on the hollow fiber membrane bioreactor were 94.0%, 99.3%, 99.9%, 69.9% and 66.9%, respectively. The estimated true biomass yield, specific denitrification rate (SDNR), specific nitrification rate (SNR) and phosphorus removal content on the flat sheet membrane bioreactor were 0.33 kgVSS/kgBOD·d, 0.043 mgNO3-N/mgVSS·d, 0.031 mgNH4-N/mgVSS·d, and 0.144 kgP/d, respectively. In addition, the estimated true biomass yield, specific denitrification rate (SDNR), specific nitrification rate (SNR) and phosphorus removal content on the hollow fiber membrane bioreactor were 0.30 kgVSS/kgBOD·d, 0.067 mgNO3-N/mgVSS·d, 0.028 mgNH4-N/mgVSS·d, and 0.121 kgP/d, respectively. There was little difference between the flat sheet and hollow fiber on the nutrient removal efficiencies except SNR and SDNR. These differences between them were caused by the air demand to prevent the membrane fouling. The flux and oxygen demand for air scouring were 19.0 L/m2/hr and 2.28 m3/min for the flat sheet membrane, and 20.7 L/m2/hr and 1.77 m3/min for the hollow fiber membrane on an average.

Flat sheet, Hollow fiber, Membrane bioreactor, SDNR, SNR

정용준 Yong Jun Jung

DOI: Vol.27(No.3) 329-333, 2011

p-phenylene-2,5-benzobisoxazole (PBO; Zylon (R)) fibers as an adsorbent were employed for solid phase extraction of aqueous alkylphenols. The removal ratios for 10 kinds of alkylphenols at initial concentration of 100 μgL-1 were in the range of 16.8-96.3% and the removals increased with the increase of the phase ratio (fiber weight/solution volume). The plots of the logarithm of partition coefficient (log K) were correlated with the logarithm of the n-octanol/water partition coefficient (log P). The adsorbed alkylphenols were completely desorbed with the mixture of acetonitrile and dichloromethane.

Alkylphenols, Log P, Partition coefficient, PBO fibers, Solid phase extraction

현재열 Jae Yeoul Hyun , 윤종호 Jong Ho Yoon

DOI: Vol.27(No.3) 334-341, 2011

The free residual chlorine of tap water samples, collected from 266 faucets on the water pipe network in Daegu City, was between 0.1 and 0.79 mg/L. On microorganic tests, general bacteria and the coliform goup were not detected and thus the tap water was turned out to be fit to drink. In particular, samples of which free residual chlorine was 0.1 mg/L and over were cultured in R2A agar media at 25˚C for 7 days, and as a result heterotrophic bacteria were detected in 65.9% of samples; (1). The closer tap water got to the faucet from the stilling basin, the lower residual chlorine concentration became but the more the bacterial count became. And, more bacteria were detected in the R2A agar medium than in the PCA medium. (2). In the case of separated strains, most colonies were reddish or yellowish. 16S rRNA sequence was identified as Methylobacterium sp. and Williamsia sp., and yellow strain was identified as Sphingomonas sp., Sphingobium sp., Novosphingobium sp., Blastomonas sp., Rhodococcus sp. and Microbacterium sp. White strain was identified as Staphylococcus sp. (3). Sterilized tap water in polyethylene bottles was inoculated with separated strain and was left as it was for 2 months. As a result, bio-film was observed in tap water inoculated with Methylobacterium sp. and Sphingomonas sp. It was found that heterotrophic bacteria increased when free residual chlorine was removed from tap water in the water pipe network. Thus, there is a need to determine a base value for heterotrophic bacteria in order to check the cleanliness of tap water in the water pipe network.

Chlorine-resistant bacteria, Daegu city, Faucets, Free residual chlorine, Water pipe network

김연석 Yeon Seok Kim , 우강화 Jiang Hua Yu , 김영철 Young Chul Kim

DOI: Vol.27(No.3) 342-348, 2011

A hydrodynamic separator using natural free energy provided by bridge was operated for the treatment of stormwater runoff. The separator was automatically controlled by using electronic valve which is connected with pressure meter. Normally the separator was opened during dry days, but it was closed after the capture of first flush. The results indicated that the average pressure and the flow rate were directly affected by the rainfall intensity. The pressure was more than 3 meters as the rainfall intensity was above 5 mm/hr. The percent volume of underflow decreased as the pressure and flow rate increased, but the percent volume of overflow showed an opposite behavior. The concentration of total suspended solids (TSS) in underflow increased as a function of increasing pressure while it decreased in overflow. The TSS separation efficiency was evaluated based on mass balance. It ranged from 30% to 90% with the pressure ranging from 2 to 10 meters, and it was proportional to pressure and flow rate. The analysis of water balance indicated that around 13% of total runoff was captured by the separator as a first flush, and this runoff was separated as underflow and overflow with the respective percent volume of 29% and 71%. The pollutants budget was also examined based on mass balance. The results showed that the percent of TSS, COD(cr), TN and TP in underflow were 73%, 59%, 7.6% and 49%, respectively.

First flush, Hydrodynamic separator, Natural free energy, Separation efficiency, Stormwater

김진이 Jin Lee Kim , 이수웅 Su Woong Lee , 김용석 Yong Seok Kim , 이석모 Suk Mo Lee

DOI: Vol.27(No.3) 349-356, 2011

This study, which evaluated the contribution of the real economic value and system in the Nakdong River Basin, estimated the emergy analysis for environmental accounting of the TMDL program. And an environmental accounting for TMDL is evaluated before and after adopting TMDL program respectively. The value of emergy after adopting the TMDL was 7.90 E+20 sej/yr. Although the real yield of the river after governmental investment was high (before: 9.7118 E+20 sej/yr and after: 9.7224 E+20 sej/yr), the effects of improvement was not great, in terms of an investment cost. The benefit/cost ratio resulted from environmental accounting has decreased from 1.493 to 1.230 due to the cost of managing treatment facilities. The method of improving water quality in the Nakdong River Basin by the TMDL program should be changed into an ecological treatment facilities using resources efficiently from a control of water quality depending on expansion of the wastewater treatment facilities and advanced treatment plant using high cost and non-renewable energies.

Benefit/cost ratio, Emergy, Environmental accounting, Nakdong River Basin, Total maximum daily Loads, TMDL

정성봉 Sung Bong Chung

DOI: Vol.27(No.3) 357-363, 2011

In spite of numerous advantages in railroads such as mass transportation, high reliability, and environmental soundness etc., the value of railroad construction is relatively underestimated compared to road. This is because the current method of evaluation focuses mainly on economic effect. In this study, considering recent research results, the environmental value of railroad construction was assessed by calculating the effect of reduction of emissions and water contamination. With these two benefits, the environmental effect produced by railroads and road construction was calculated and compared to each other using EMME/3. As a result, the senario 4 which considers ``Hot/Cold start`` condition and water contamination had highest benefits. Furthermore, the environmental effect produced by railroad is 55~101% higher than road construction. If the suggested method is used in the current appraisal system, the environment-friendly mode like railway would be highly valued, much more than before.

EMME/3, Environment-friendly mode, Hot/Cold start, Investment appraisal system, Railroad construction

안윤주 Youn Joo An , 남선화 Sun Hwa Nam

DOI: Vol.27(No.3) 364-370, 2011

Water quality criteria for human health protection are derived based on the human health risk assessment. Water quality criteria in Korean freshwater bodies have been derived according to the equations developed by the US Environmental Protection Agency. The equations include the fish intake parameter, which is very important factor that significantly influences on the criteria derivation. So far, several fish intake values were used in human health risk assessment for water quality standards and effluent standards. However, these values are not consistent and they refer to various sources. Therefore, there is a need to suggest the most appropriate value of fish intake parameter to derive freshwater quality criteria in Korea. In this study, national and international fish intake values were widely collected and evaluated to select the adequate value of fish intake parameter that can be applied in Korea. The USEPA presented fish intake parameter as the 17.5 g/day for general adults and sport fishers and 142.4 g/day for subsistence fishers. In Korean reports, wide range values of 2 to 67.7 g/day were suggested as fish intake value. These values included finfish and shellfish intakes in common but had various habits. This study found that the 52.4 g/day suggested in Korean Exposure Factors Handbook published by the Ministry of Environment in 2007 seemed to be the suitable fish intake parameter to derive the freshwater quality criteria in Korea. The value is based on water corrected intakes of finfish and shellfish present in freshwater and coastal areas. We expect that this report can be useful to select suitable fish intake value in human health risk assessment for establishing freshwater quality standard in Korea.

Criteria, Fish intake, Freshwater, Human health risk assessment

박재홍 Jae Hong Park

DOI: Vol.27(No.3) 371-376, 2011

If animal disease, i.e., livestock foot-and-mouth disease, avian influenza, brings out, animals have to be disposed to prevent the virus spreading. Mainly, animals have been disposed by carcass disposal. However, If not done properly, carcass disposal can lead to environmental problems, i.e., soil and ground water pollution, etc. Therefore, various disposal methods, i.e., rendering, cremation, etc., have to be considered with burial. Also, various supplement policies are needed to prevent the animal disease. The purpose of this study was to find effective solutions for the prevention and biosecurity of animal disease.

Animal burial, Avian influenza, AI, Biosecurity, Livestock foot-and-mouth disease