임지열 Ji Yeol Im , 길경익 Kyung Gik Gil

DOI: Vol.27(No.5) 563-571, 2011

The purpose of this study is to investigate the high strength ammonia oxidation of piggery wastewater. Laboratory scale reactors was operated using influent of piggery wastewater and effluent of anaerobic digester from piggery wastewater at 35℃ and 20℃. Results of various operating conditions were compared and analyzed. After analyzing the results, effluent of anaerobic digester from piggery wastewater required shorter Solid retention time (SRT) than influent of piggery wastewater. In terms of the temperature, stable ammonia removal and denitrification was achieved on the both of the condition. At the temperature of 35℃, nitrite conversion rate was better than 20℃. It can be concluded that treating the piggery wastewater using anaerobic digester on the condition of the temperature at 35℃ is more efficient on the nitritation of the piggery wastewater.

Ammonia, Nitiritation, Nitrogen, Piggery wastewater

원철희 Chul Hee Won , 최용훈 Yong Hun Choi , 신민환 Min Hwan Shin , 신동석 Dong Suk Shin , 강동구 Dong Gu Kang , 최중대 Joong Dae Choi

DOI: Vol.27(No.5) 572-579, 2011

We have examined the runoff characteristics of nonpoint source (NPS) in fields. Two monitoring sites were equipped with an automatic velocity meter and water sampler. Monitoring was conducted at fields 1 and field 2 during the rainfall event. Ten rainfall-runoff events were monitored and analyzed during the study period. The results show that runoff occurred if daily rainfall and intensity were higher than 40 mm and 1.6 mm/hr except a few extreme rainfall events with very high intensity. Runoff of field 1 was approximately twice of that of field 2. Event mean concentrations (EMC) and pollution load of analyzed water quality indices were also higher in field 2 than in field 1. Especially, TN load from field 2 was 75.4 mg/m2 and was about 5 times higher than that from field 1. Analysis of Pearson correlation coefficient of water quality parameter indicates that besides of TN all items in fields 1 have tight relationship respectively (p < 0.01). But those of fields 2 have a significant (p < 0.05). Estimating units loading of NPS, we suggested that variable such as soil texture, rainfall amount and intensity and slope were needed to be considered from agricultural landuses. The results of this study can be used as a basic data in the development and implementation of total maximum daily loads (TMDL) in Korea.

Event mean concentrations, EMC, Pearson correlation coefficient, Pollution Load, Total maximum daily Loads, TMDL, Unit Loading

김정진 Jung Jin Kim , 김태동 Tae Dong Kim , 최동현 Dong Hyuk Choi , 전지홍 Ji Hong Jeon

DOI: Vol.27(No.5) 580-586, 2011

Low impact development (LID) technique is recently proposed as new concept to reduce surface runoff and pollutant loading with various best management practices (BMPs). In this study, LIDMOD2, which is one of the model to evaluate LID, was applied at Mohyeon developing area to evaluate the redcution of annual runoff and pollution loading, cost-reduction efficient by LID with design of structural BMPs including bioretention, wet pond, and wetland. As a simulation results, the bioretention had the highest reduction efficiency for runoff (41.43%), and 22% for T-N and 22% for BOD. Wet pont had the highest reduction efficiency for T-P as showing 25% of reduction rate. As a results of cost-reduction efficient, wet pont represented the highest cost-effective for T-N and BOD with showing 0.43 T-P kg/million won and 17.37 BOD kg/million won, respectively, and bioretention represented the highest cost-effective for T-P with showing 2.52 T-P kg/million won. LID technology could reduce effectively surface runoff and nonpoint source pollution and construct sustainable development. LIDMOD2 could be suggested as useful tool to evaluate and design LID.

LIDMOD2, Low impact development, LID, Nonpoint source pollution, Structural BMPs

박인혁 In Hyeok Park , 박진혁 Jin Hyeog Park , 허영택 Young Teck Hur

DOI: Vol.27(No.5) 587-596, 2011

The interest in hydrological modeling has increased significantly recently due to the necessity of watershed management, specifically in regards to lumped models, which are being prosperously utilized because of their relatively uncomplicated algorithms which require less simulation time. However, lumped models require empirical coefficients for hydrological analyses, which do not take into consideration the heterogeneity of site-specific characteristics. To overcome such obstacles, a distributed model was offered as an alternative and the number of researches related to watershed management and distributed models has been steadily increasing in the recent years. Thus, in this study, the feasibility of a grid-based rainfall-runoff model was reviewed using the flood runoff process in the Han River basin, including the ChungjuDam, HoengseongDam and SoyangDam watersheds. Hydrological parameters based on GIS/RS were extracted from basic GIS data such as DEM, land cover, soil map and rainfall depth. The accuracy of the runoff analysis for the model application was evaluated using EFF, NRMSE and QER. The calculation results showed that there was a good agreement with the observed data. Besides the ungauged spatial characteristics in the SoyangDam watershed, EFF showed a good result of 0.859.

Distributed model, Flood runoff, Grids, Numerical analysis

김태원 Tae Won Kim , 길경익 Kyung Ik Gil

DOI: Vol.27(No.5) 597-604, 2011

This research analyzed the runoff patterns and estimated unit loads of selected pollutatnts using monitored data conducted for three years in a bridge area. Three estimating methods; the arithmetic average method, the regression method and the rainfall class method were used to estimate the unit load. Results of three estimating methods were compared with the unit pollutant loads from landuses in Korea and the unit pollutant loads from urban watersheds in Milwaukee, USA. Unit load using the arithmetic mean method were found to be overestimated. In terms of TSS, unit loads of two estimate were half lower than that of USA. Estimated TN and TP unit loads of three estimate were lower than that of Ministry of Environment in Korea.

Arithmetic average method, Nonpoint sources, Pollutant unit Load, Rainfall class method, Regression method

권헌각 Hun Gak Kwon , 이재운 Jae Woon Lee , 이윤정 Youn Jeong Yi , 윤영삼 Young Sam Yoon , 이춘식 Chun Sik Lee , 이재관 Jae Kwan Lee

DOI: Vol.27(No.5) 605-616, 2011

The first flush phenomenon and the Mass First Flush (MFFn) were analyzed for various rainy events in trunk road. Applicability for estimate MFFn using SWMM was evaluated by comparision with observed MFFn. First flush phenomenon was investigated by normalized cumulated (NCL) curve of every pollutant based on ten times of rainfall events monitoring data from 2008 to 2009. As a result, magnitude of first flush phenomenon varied with the pollutants and rainfall events. First flush phenomenon was detected highly in the trunk road. MFFn was estimated by varying n-value from 10 to 90% on the rainfall events. The n-value increases, MFFn is closed to ``1``. As time passed, the rainfall runoff was getting similar to ratio of pollutants accumulation. The result of a measure of the strength of the linear relationship between observed data and expected data under model was good (R2=0.956). As the final outcome, we have good reliability, estimation and application of MFFn using model seem statistically possible.

First flush phenomenon, Mass first flush, MFFn, SWMM, Trunk road

김동석 Dong Seog Kim , 박영식 Young Seek Park

DOI: Vol.27(No.5) 617-624, 2011

In order to confirm the creation of the OH radical which influences to RNO bleaching processes, it experimented using laboratory reactor of dielectric barrier discharge plasma (DBDP). The experiments performed in about 4 kind process variables (diameter of ground electrode, diameter of discharge electrode, diameter of quartz tube and effect of air flow rate) which influence to process. In order to examine optimum conditions of design factors as shown in Box-Behnken experiment design, ANOVA analysis was conducted against four factors. The actual RNO removal at optimized conditions under real design constraints were obtained, confirming Box-Behnken results. Optimized conditions under real design constraints were obtained for the highest desirability at 1, 1 mm diameter of ground and discharge electrode, 6 mm diameter of quartz tube and 5.05 L/min air flow rate, respectively.

Box-Behnken method, Dielectric barrier discharge, Plasma, Response surface method, Water treatment

이보미 Bo Mi Lee , 이태환 Tae Hwan Lee , 허진 Jin Hur

DOI: Vol.27(No.5) 625-633, 2011

A long-term water quality monitoring in the Han River Basin reveals a consistent increasing trend for the concentration of refractory organic matter (R-OM) in major monitoring sites of the watershed. Because the determination of R-OM concentrations typically requires a long time of microbial incubation, it is essential to present the estimation indices for R-OM for an efficient watershed management. In this study, a number of surface water samples were classified into three groups, each of which were collected from Lake Paldang, rivers at rain and non-rain events, respectively. The corresponding R-OM concentrations were correlated with biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total organic carbon (TOC) concentrations as well as ultraviolet and fluorescence intensities of the filtered samples. Among the traditional organic matter parameters, TOC exhibited the highest correlation coefficient with the R-OM concentrations regardless of the types of the sample groups. The equations for conversing TOC into R-OM concentrations were finally suggested as 0.43×TOC+1.12, 0.44×TOC+0.61, 0.24×TOC+1.28 for river samples at rain and non-rain events, and lake samples, respectively. TOC-BOD(C), the values of the TOC concentrations subtracted by carbon-converted BOD concentrations, was a good index for estimating the absolute concentrations of R-OM. UV absorbance at 254 nm was well correlated with R-OM concentrations of river samples while fluorescence intensities at 350 nm showed an excellent relationship with R-OM concentration of the lake samples. Our results suggests that simple spectroscopic parameters could be applied for in-situ monitoring tool techniques in watersheds.

Conversion equation, Fluorescence spectroscopy, Organic matter index, Refractory organic matter, UV absorbance

최치현 Chi Hyun Choi , 박무종 Moo Jong Park , 백천우 Chun Woo Baek , 김상단 Sang Dan Kim

DOI: Vol.27(No.5) 634-645, 2011

A newly developed rainwater harvesting (RWH) system reliability model is evaluated for roof area of buildings in Haeundae District of Busan. RWH system is used to supply water for toilet flushing, back garden irrigation, and air cooling. This model is portable because it is based on a non-parametric precipitation generation algorithm using a markov chain. Precipitation occurrence is simulated using transition probabilities derived for each day of the year based on the historical probability of wet and dry day state changes. Precipitation amounts are selected from a matrix of historical values within a moving 30 day window that is centered on the target day. Then, the reliability of RWH system is determined for catchment area and tank volume ranges using synthetic precipitation data. As a result, the synthetic rainfall data well reproduced the characteristics of precipitation in Busan. Also the reliabilities of RWH system for each of demands were computed to high values. Furthermore, for study area using the RWH system, reduction efficiencies for rooftop runoff inputs to the sewer system and potable water demand are evaluated for 23%, 53%, respectively.

Non-parametric stochastic rainfall generation algorithm, Potable water, Rainwater Harvesting System, Reliability

이한샘 Han Saem Lee , 한종훈 Jong Hun Han , 윤주환 Zu Whan Yun

DOI: Vol.27(No.5) 646-653, 2011

The combined system of sequencing batch biofilm reactor (SBBR) and membrane SBR (MSBR) was operated with sewage to evaluate the COD utilization for biological nutrient removal (BNR). The SBBR was operated for nitrification reactor, while denitrifying PAO (dPAO) was cultivated in MSBR with anaerobic-anoxic operation. In the SBBR and MSBR system, the enhanced biological phosphorus removal (EBPR) was successfully achieved with higher N removal. The COD utilization in combined SBBR-MSBR system was significantly reduced compared to ordinary BNR (up to 3.1 g SCOD/g (N+P) and 1.6 g SCOD/g (N+P) with different C/N/P ratio). The results suggest that a dPAO process could effectively reduce carbon energy (=COD) requirement. The combination of oxic-SBBR and anaerobic-anoxic MSBR for dPAO utilization could be an attractive alternative to upgrade the process performance in weak sewage.

COD utilization, Denitrifying PAO, dPAO, Membrane SBR, MSBR, Sequencing batch biofilm reactor, SBBR

손봉호 Bong Ho Son , 어성욱 Seong Wook Oa

DOI: Vol.27(No.5) 654-660, 2011

One of the best way to control Combined Sewer Overflow (CSO) is proposed to construct first flush storage tank. But there is little known parameters for optimum design of these facilities. This study was conducted to get optimum design parameters for a first flush storage tank construction. The optimization of the tank is generally based upon some measure of SS(Suspended Solid) mass holding efficiency. Water quality deterioration of receiving water body happened right after first time occurring rainfall in dry weather seasons. So, design rainfall intensity is used at 2 mm/hr for peak of monthly average intensities of dry seasons. The capacities for each evaluated catchment are designed from 14.4 min to 16.1 min HRT of CSOs flow at design rainfall intensity. Owing to all storage tanks are connected to interception sewer having a redundancy, the suggested volume could be cut down.

Combined Sewer Overflows, CSOs, First flush, Rainfall Intensity, Receiving water quality, Runoff storage tank

윤여진 Yeo Jin Yoon , 김주철 Joo Cheol Kim

DOI: Vol.27(No.5) 661-669, 2011

The purpose of this study is quantitative analysis of the effects of the interactions between stream network and hillslope to hydrologic response functions. To this end general formulation of hydrologic response function is performed based on width function and grid framework. Target basins are Ipyeong and Tanbu basins. From the results of width function estimation even similar sized and closely located basins could have very different hydrologic response function. It is found out that the interactions between stream network and hillslope are essential factors of rainfall-runoff processes because their difference can make the hydrologic response function with positive skewness. The change of velocities of stream network and hillslope might influence the magnitude of peak but time to peak tends to more sensitively respond to velocities of stream network. Lag time of basin would be the result of complex interaction between drainage structures and dynamic properties of river basin.

Hillslope, Hydrologic response function, Rescaled width function, Stream network

강태욱 Tae Uk Kang , 이상호 Sang Ho Lee , 김일규 Il Kyu Kim , 이남주 Nam Ju Lee

DOI: Vol.27(No.5) 670-679, 2011

Chlorophyll-a is a major water quality indicator for an algal bloom in streams and lakes. The purpose of the study is to estimate chlorophyll-a concentration in tributaries of the Seonakdonggang by an artificial neural network (ANN). As the tributaries are ungauged streams, a watershed runoff and quality model was used to simulate water quality parameters. The tributary watersheds include urban area and thus Storm Water Management Model (SWMM) was used to simulate TN, TP, BOD, COD, and SS. SWMM, however, can not simulate chlorophyll-a. The chlorophyll-a series data from the tributaries were estimated by the ANN and the simulation results of water quality parameters using SWMM. An assumption used is as follows: the relation between water quality parameters and chlorophyll-a in the tributaries of the Seonakdonggang would be similar to that in the mainstream of the Seonakdonggang. On the assumption, the measurement data of water quality and chlorophyll-a in the mainstream of the Seonakdonggang were used as the learning data of the ANN. Through the sensitivity analysis, the learning data combination of water quality parameters was determined. Finally, chlorophyll-a series were estimated for tributaries of the Seonakdonggang by the ANN and TN, TP, BOD, COD, and temperature data from those streams. The relative errors between the estimated and measured chlorophyll-a were approximately 40~50%. Though the errors are somewhat large, the estimation process for chlorophyll-a may be useful in ungauged streams.

Artificial neural network, Chlorophyll-a, Storm Water Management Model, SWMM, Ungauged stream

손세환 Se Hwan Son , 김진영 Jin Young Kim , 조재익 Jae Ick Jo , 공동수 Dong Soo Kong

DOI: Vol.27(No.5) 680-688, 2011

This study was performed to find out the distribution aspect of benthic macroinvertebrates according to altitude in a mountain stream (a main stream: Buk stream, a tributary: Hangye stream) of Seoraksan. The survey was conducted from August to November in 2010. All survey sites were very sound because the mountain was being maintained as a protection area of the national park. Water quality and the composition of substrata were similar in all sites. Benthic macroinvertebrates of 3 phyla, 4 classes, 9 orders and 84 species occurred in the stream. Along with the decline of altitude, shredders of the functional feeding groups (FFGs) decreased, while collector filterers increased. In particular, collector filterers increased sharply at the altitude of 600~500 m (S.E.L.). Benthic macroinvertebrates showed low similarity between the uppermost site and the lower sites. Altitude appeared to be a significant factor that influence the structure and distribution of benthic macroinvertebrate community.

Altitudinal distribution, Benthic macroinvertebrate, Functional feeding group, Mountain stream

강현우 Hyun Woo Kang , 류지철 Ji Chul Ryu , 신민환 Min Hwan Shin , 최중대 Joong Dae Choi , 최재완 Jae Wan Choi , 신동석 Dong Seok Shin , 임경재 Kyoung Jae Lim

DOI: Vol.27(No.5) 689-698, 2011

In South Korea, Total Maximum Daily Load (TMDL) has been enforced since 2004 to restore and manage water quality in the watersheds. However, the appraisal of TMDL in South Korea has lots of weaknesses to establish the plan for recovery of water quality because it just evaluates the target water quality during the particular flow duration interval. In the United States, Load Duration Curve (LDC) method bas been widely used in the TMDL to evaluate the water quality and pollutant loads considering variation of stream flow. In a recent study, web-based Load Duration Curve system was developed to create the LDC automatically and provide the convenience of use. In this study, web-based Load Duration Curve system was applied in the Gapyeongcheon watershed using the daily flow and 8-day interval water quality data, and Q-L Rating Curve was used to evaluate the water quality and pollutant load in the watershed, also. As a result of study, water quality and pollutant load in Gapyeongcheon watershed were met with water quality standard and allocated load in the all flow durations. Web-based Load Duration Curve system could be applied to the appraisal of South Korean TMDL because it can be used to judge the impaired flow duration and build up the plan of load reduction, and it could enhance the publicity. But, web-based Load Duration Curve system should be enhanced through addition of load assessment tools such as Q-L rating curve to evaluate water quality and pollutant load objectively.

Pollutant Load, Q-L rating curve, TMDL, Water quality, Web-based Load duration curve

이흥수 Heung Soo Lee , 정세웅 Se Woong Chung , 최정규 Jung Kyu Choi , 오동근 Dong Geun Oh , 허태영 Tae Young Heo

DOI: Vol.27(No.5) 699-709, 2011

The uses of multi-dimensional hydrodynamic and water quality models are increasing to support a sustainable management of large dam reservoirs in Korea. Any modeling study requires selection of a proper spatial dimension of the model based on the characteristics of spatial variability of concerned simulation variables. For example, a laterally averaged two-dimensional (2D) model, which has been widely used in many large dam reservoirs in Korea, assumes that the lateral variations of hydrodynamic and water quality variables are negligible. However, there has been limited studies to give a justification of the assumption. The objectives of this study were to present the characteristics of spatial variations of water quality variables through intensive field monitoring in Daechung Reservoir, and provide information on a proper spatial dimension for different water quality parameters. The monitoring results showed that the lateral variations of water temperature are marginal, but those of DO, pH, and conductivity could be significant depending on the hydrological conditions and local algal biomass. In particular, the phytoplankton (Chl-a) and nutrient concentrations showed a significant lateral variation at R2 (Daejeongri) during low flow periods in 2008 possibly because of slow lateral mixing of tributary inflow from So-oak Stream and wind driven patchiness.

Daechung reservoir, Model dimension, Reservoir water quality, Spatial variations

김유경 Yu Kyung Kim , 정세웅 Se Woong Chung

DOI: Vol.27(No.5) 710-718, 2011

An integrated water quality management of reservoir and river would be required when the quality of downstream river water is affected by the discharge of upstream dam. In particular, for the control of downstream turbidity during flood events, the integrated modeling of reservoir and river is effective approach. This work was aimed to develop a laterally-averaged two-dimensional hydrodynamic and water quality model (CE-QUAL-W2), by which water quality can be predicted in the downstream of Yongdam dam in conjunction with the reservoir model, and to validate the model under two different hydrological conditions; wet year (2005) and drought year (2010). The model results clearly showed that the simulated data regarding water elevation and suspended solid (SS) concentration are well corresponded with the measured data. In addition, the variation of SS concentration as a function of time was effectively simulated along the river stations with the developed model. Consequently, the developed model can be effectively applied for the integrated water quality management of Yongdam dam and downstream river.

CE-QUAL-W2, Laterally-averaged two-dimensional modeling, Turbidity modeling, Yongdam dam

박재홍 Jae Hong Park , 류덕희 Doug Hee Rhew , 정동일 Dong Il Jung

DOI: Vol.27(No.5) 719-728, 2011

The results of investigation on the water quality of the unit watersheds in the Yeongsang/Seomjin River indicate that BOD5, SS, T-P decrease in most of the unit watersheds. However, CODMn and T-N increase since the Total Maximum Daily Loads (TMDLs). It is thought that CODMn, which is included non-biodegradable matters, is difficult to decrease only using by conventional biological treatment facilities and T-N is affected by non-point source, etc. The results of assessment on 3 years BOD5 indicate that most of the unit watersheds were being improved except Yeongbon A, Seombon C and Yocheon B. In addition, it was found that T-P were also being improved except Yocheon B and Hwangryeong A. Consequently, water qualities of the unit watersheds have been improved in many cases since the TMDLs.

BOD5, Target water quality, T-P, Water quality assessment