김금용 Keum Yong Kim , 강민구 Min Koo Kang , 신관우 Gwan Woo Shin , 강정규 Jung Kyu Kang , 신민수 Min Su Shin , 강한솔 Han Sol Kang , 이상일 Sang Ill Lee

DOI: Vol.29(No.1) 1-6, 2013

This study was focused on improving nitrification efficiencies of M-dephanox (Modified-Dephanox) process. Rotating biological contactor was used instead of floating sponge type media in nitrification reactor. High ammonia removal efficiencies were observed in nitrification reactor regardless of organic loading from contactor of M-dephanox process. Denitrification efficiencies were also increased to maintain low NO₃-N concentration in effluent. This enhanced phosphate release in anaerobic contactor and resulted in high removal efficiencies of phosphorus. Average removal efficiencies of TCOD_Cr and SCOD_Cr were 93.8% and 81.6% respectively while those of TKN and NH₄+^-N were 80.9% and 74.4% respectively. As for phosphorous treatment the average removal efficiencies of TP and OP were 94.7% and 94.3% respectively. Also effect of operating temperature on nitrogen removal was examined. Average removal efficiency of TN was 65.8 % at 15℃ or below (at average temperature of 13.3℃) while that was 82.8% at 15℃ or above (at average temperature of 21.9℃).

C, N ratio, M-dephanox, Nitrification, Rotating Biological Contactor, Temperature

박혜경 Hae Kyung Park , 이장호 Jangho Lee , 윤석환 Seuk Hwan Yun , 최명재 Myung Jae Choi

DOI: Vol.29(No.1) 7-18, 2013

We compared the structure of fish community and condition of major fish species in Lake Chungpyung and Lake Paldang which are relatively shallow meso-eutrophic cascading dam reservoirs on the North Han River. Two lakes have wide littoral zone in the lakeside providing similarly good habitat for fishes whereas fishery and water recreational activities such as motorboating water skiing are allowed in Lake Chungpyung but are prohibited in Lake Paldang. The average lengths of large size fishes in Lake Chungpyung are shorter than those of same species in Lake Paldang resulting in the slight distortion of generation distribution of those species in Lake Chungpyung possibly owing to the active fishery such as fixed shore net fishing gill net fishing and angling. Meanwhile the condition of fishes represented by the length-weight relationship of fish species did not show the significant differences between two lakes and showed normal condition. To evaluate the impact of physical disturbance such as loud noise and turbulent wave from water recreational activities to fishes precisely further studies including physiological responses to stress an spawing activity should be needed.

Fish community, Fishery Lake, Chungpyung, Lake Paldang, Length-weight relation, Water recreational activities

박혜경 Hae Kyung Park , 김은경 Eun Kyoung Kim

DOI: Vol.29(No.1) 19-28, 2013

Artificial neural networks were used for time series modelling of algal dynamics of whole year and by season at the Paldang dam station (confluence area). The modelling was based on comprehensive weekly water quality data from 1997 to 2004 at the Paldang dam station. The results of validation of seasonal models showed that the timing and magnitude of the observed chlorophyll a concentration was predicted well compared with the ANN model for whole year. Internal weightings of the inputs in trained neural networks were obtained by sensitivity analysis for identification of the primary driving mechanisms in the system dynamics. pH COD TP determined most the dynamics of chlorophyll a although these inputs were not the real driving variable for algal growth. Short-term prediction models that perform one or two weeks ahead predictions of chlorophyll a concentration were designed for the application of Harmful Algal Alert System in Lake Paldang. Short-term-ahead ANN models showed the possibilities of application of Harmful Algal Alert System after increasing ANN model`s performance.

Algal bloom, Artificial neural network, Lake Paldang, Sensitivity analysis, pH, Short-term-ahead models

금동혁 Donghyuk Kum , 유지철 Jichul Ryu , 최재완 Jaewan Choi , 강형우 Hyunwoo Kang , 장춘화 Chun Hwa Jang , 신동석 Dong Suk Shin , 이재관 Jae Kwan Lee , 임경재 Kyoung Jae Lim

DOI: Vol.29(No.1) 29-35, 2013

Recently various Best Management Practices have been applied at a field to reduce soil erosion. Hourly Runoff and Sediment Model for Best Management Practices (HRSM4BMP) model could be used to evaluate soil erosion reduction for various agricultural BMPs at fields. Runoff and sediment yield from source areas have to be predicted with greater accuracies to evaluate sediment reduction efficiently with BMPs. To achieve this the best parameters related with runoff and sediment modules of the HRSM4BMP model should be identified with proper calibration processes. Although manual calibration is often utilized in calibrating runoff and sediment using the HRSM4BMP objective calibration method would be recommended. The purpose of the study was to develop an automatic calibration tool of the HRSM4BMP model with PARASOL method. This automatic calibration tool was applied to Bangdongri Chuncheon-si to evaluate its calibration performance. The R² NSE and RMSE value for runoff estimation were 0.92, 0.92, 0.3 m³ and for sediment yield estimation were 0.94 0.94 0.0027kg. As shown in this result automatic calibration tool of HRSM4BMP model would be used to determine the best parameters and can be used to simulate runoff and sediment yield with acceptable accuracies.

Automatic calibration, HRSM4BMP model, PARASPL, Runoff, Sediment yield

강형식 Hyeongsik Kang , 장재호 Jae Ho Jang

DOI: Vol.29(No.1) 36-44, 2013

HSPF model based on BASINS was applied to analyze effects of watershed management measures for water quality conservation in the Hwaseong Reservoir watershed. The model was calibratcd against the field measurements of meteorological data streamflow and water qualities (BOD_5 T-N T-P) at each observatory for 4years (2007-2010). The water quality characteristics of inflow streams were evaluated. The 4 scenarios for the water quality improvement were applied to inflow streams and critical area from water pollution based on previous researches. The reduction efficiency of point and non-point sources in inflow streams was evaluated with each scenario. The results demonstrate that the expansion of advanced treatment system within wastewater treatment plants and construction of pond-wetlands would be great effective management measures. In order to satisfactory the target water quality of reservoir the measures which can control both point source and non-point source pollutants should be implemented in the watershed.

BASINS, HSPF model, Hwaseong reservoir watershed, Target water quality, Watershed management measures, Water quality conservation

박청열 Changyeol Park , 신상영 Sang Young Shin , 손은정 Eun Jung Son

DOI: Vol.29(No.1) 45-54, 2013

This study analyzes the reduction effects of runoff and flood damage through different arrangements of stormwater storage facilities. Three scenarios based on the spatial allocation of storage capacity are used: concentrated decentralized and combinative. The characteristics of runoff and flood damage by scenario are compared. The XP-SWMM model is used for runoff simulation by the probable rainfall of return period. The result shows that the concentrated arrangement of storage facilities is most effective to reduce the amount of peak flow and to delay the time of peak flow. Yet while the concentrated arrangement is most effective to reduce the inundation damage it is not effective to reduce runoff volume. The decentralized arrangement is most effective to reduce runoff volume. The combinative arrangement is effective not only the runoff reduction but also the reduction of flood damage. The result indicates that the flood mitigation strategies against heavy rainfall need to consider decentralized on -site arrangement for the reduction of runoff volume along with concentrated off-site arrangement of storage facilities.

Flood damage, Runoff reduction, Storm water storage facilities, XP-SWMM

박준대 Jun Dae Park , 오승영 Seung Young Oh

DOI: Vol.29(No.1) 55-65, 2013

It is very difficult to apply stream flow data directly to the management of Total Maximum Daily Loads because there are some differences between the unit watershed and the stream flow monitoring network in their characteristics such as monitoring locations and its intervals. Flow duration curve can be developed by linking the daily flow data of stream monitoring network to 8 day interval flow data of the unit watershed. This study investigated the current operating conditions of the stream flow monitoring network and the flow relationships between the unit watershed and the stream flow monitoring network. Criteria such as missing and zero value data and correlation coefficients were applied to select the stream flow reference sites. The reference sites were selected in 112 areas out of 142 unit watersheds in 4 river basins where the stream flow observations were carried out in relatively normal operating conditions. These reference sites could be utilized in various ways such as flow variation analysis flow duration curve development and on for the management of Total Maximum Daily Loads.

8 day interval flow data, Daily flow data, Flow duration curve, Stream flow monitoring network, Stream flow reference sites, Total maximum daily loads, Unit watershed

박재홍 Jae Hong Park , 박배경 Bae Kyoung Park , 오승영 Seung Young Oh , 황하선 Ha Sun Hwang , 이재관 Jae Kwan Lee

DOI: Vol.29(No.1) 66-73, 2013

Total Maximum Daily Loads system was introduced to manage pollution load of watershed and to improve water quality of unit watershed so that it is possible to protect drinking water soureces. Load allocation observation is the most important factor in TMDLs system. Because if load allocation is not observed it is difficult to achieve water quality goal of unit watershed. Also it is impossible to improve water quality of the drinking water sources. Therefore it is necessary to apply some kind of sanctions (penalty) in case of excess of load allocation. The sanctions have to be however applied differently based on various reduction plan types i.e using the reduction load planed in 2nd phase delay the completion additional reduction in 2nd phase error of the pollution sources etc Moreover the penalty load should be properly imposed lest it should be overburden the provence. The reduction load trade inter province must be restrictively permitted only the same unit watershed.

Excess of load allocation, Penalty, Reduction load, Water quality goal

윤여준 Yeojoon Yoon , 박문기 Moonki Park , 권민환 Minhwan Kwon , 정유미 Youmi Jung , 강준원 Joon Wun Kang

DOI: Vol.29(No.1) 74-80, 2013

The aim of this study is to evaluate color removal from leather-dyeing wastewater using O₃ and O₃/H₂O₂ unit processed and a serial process for O₃ followed by the O₃/H₂O₂ process. The color removal rate of the O₃ alone process was only 65% effective and the color increased when an applied O₃ dose of more than 40~50 ㎎/L was applied. On the other hand the color was completely removed without increments of color by the O₃/H₂O₂ process with H₂O₂ injection ratio of 0.2 and 0.3(wt. H₂O₂/wt. O₃). Even though the injection of H₂O₂ had an effect on color removal rates from O₃ alone and from O₃/H₂O₂ were similar up to the initial O₃-demand stage with an application of 0~40 mg/L O₃. In conclusion it was found that the O₃ followed by the O₃/H₂O₂ serial process the method injecting H₂O₂ after ozonation with O₃-demand(30~40mg/L) in the first stage is the most appropriate process for effective color removal from leather-dyeing wastewater.

Color removal, H₂O₂, Leather-dyeing wastewater, O₃, O₃-demand, Serial process

신재원 Jae Won Shin , 이보미 Bo Mi Lee , 허진 Jin Hur , 박지형 Ji Hyung Park

DOI: Vol.29(No.1) 81-87, 2013

Changes of organic carbon after the entrance into dam reservoirs were investigated using water samples collected in May September and October in 2010 from the inflow sites and the outlets of four selected dam reservoirs-Soyang Chungju Chungju regulation and Uiam. Increase of refractory disslolved organic carbon was observed only for large dam reservoirs with long residence times whereas the trend was not found for relatively small reservoirs. The effects of residence times on organic carbon changes were further confirmed by significant postitive correlations between monthly residence times and the relative increase of either dissolved organic carbon or R-DOC concentrations. Comparison of spectroscopic characteristics of DOC revealed that the changes in large reservoirs in May might result from in-lake processes. The inflow of terrestrial sources of DOM during storms appears to largely affect the DOC quality of the large reservoirs for the rest of the sampling periods. The mechanism however did not fully explain the behaviors of DOC for the small sized reservoirs. Our combined results suggested that both residence time and the input of allochthonous carbon sources might substantially influence the quantity of DOC as well as its quality in dam reservoirs.

Allochthonous, Autochtonous, Dam reservoirs, Refractory organic carbon, Residence time

이지민 Ji Min Lee , 금동혁 Donghyuk Kum , 김영석 Young Sug Kim , 감윤즁 Yun Jung Kim , 강현우 Hyunwoo Kang , 장춘화 Chun Hwa Jang , 이관재 Gwan Jae Lee , 임경재 Jae Lim Kyoung

DOI: Vol.29(No.1) 88-96, 2013

Much attention has been needed in water resource management at the watershed due to drought and flooding issues caused by climate change in recent years. Increase in air temperature and changes in precipitation patterns due to climate change are affecting hydrologic cycles such as evaporation and soil moisture. Thus these phenomena result in increased runoff at the watershed. The soil and water assessment tool model has been used to evaluate rainfall-runoff at the watershed reflecting effects on hydrology of various weather data such as rainfall temperature humidity solar radiation wind speed. For bias-correction of RCP data, at least 30 year data are needed. However for most gaging stations only precipitation data have been recorded and very little stations have recorded other weather data. In addition the RCP scenario does not provide all weather data for the SWAT model. In this study two scenarios were made to evaluate whether it would be possible to estimate strearmflow using measured precipitation and long-term average values of other weather data required for running the SWAT. With mcasurcd long -term weather data (scenario 1) and with long-term average values of weather data except precipitation(scenario 2) the estimate streamflow values were almost the same with NSE value of 0.99. Increase/decrease by ±2% ±4% in temperature and humidity data did not affect streamflow. Thus the RCP precipitation data for Hongcheon watershed were bias-corrected with measured long-term precipitation data to evaluate effects of climate change on streamflow. The results revealed that estimated streamflow for 2055s was the greatest among data for 2025s and 2085s. However estimated streamflow for 2085s decreased by 9% In addition streamflow for Spring would be expected to increase compared with current data and streamflow for Summer will be decreased with RCP data. The results obtained in this study indicate that the streamflow could be estimated with long-term precipitation data only and effects of climate change could be evaluated using precipitation data as shown in this study.

Future precipitation, RCP8.5 scenario, Runoff simulation, SWAT

이흥수 Heung Soo Lee , 신명종 Myung Jong Shin , 윤성완 Sung Wan Yoon , 정세웅 Se Woong Chung

DOI: Vol.29(No.1) 97-106, 2013

The temporal and spatial variations of water quality in a stratified reservoir are fully dependent on the characteristics of inflow loading from its watershed and the transport regimes of pollutants after entering the reservoir. Because of the meteorological and hydrological conditions in Korea the pollutants loading to reservoirs mostly occur during rainfall events. Therefore it is important to understand the characteristics of pollutants loading from upstream rivers and their spatial propagation through the stratified reservoir during the rainfall events. The objectives of this study were to characterize the water quality variations in upstream rivers of Imha Reservoir during a rainfall event and the transport and spatial variations of pollutants in the reservoir through extensive field monitoring and laboratory analysis. The results showed that the event mean concentration of SS BOD COD_mn T-N T-P PO₄-P are 8.6~362.1 2.5~5.1 1.5~5.1 1.1~1.9 8.3~57.1 5.6~25.7 times greater than the mean concentrations of these parameters during non-rainfall period. The turbidity and SS data showed good linear correlations but the relationships between flow and SS showed large variations because of hysteresis effect during rising and falling periods of the flood. The ratio of POC to TOC were 12.6~14.7% during the non-rainfall periods but increased up to 28.2~41.7% during the flood event. The turbid flood flow formed underflow and interflow after entering the reservoir and delivered a great amount of non-point pollutants such as labile and refractory organic matters and nutrients to the metalimnion layer of reservoir which is just above the thermocline. Spatially the lateral variations of most water quality parameters were marginal but the vertical variations were significant.

Imha Reservoir, Inflow water quality, Pollutant runoff, Rainfall event, Spatial variations

박성현 Sang Hyun Park , 문은호 Eun Ho Moon , 조병욱 Byung Wook Cho , 최정호 Jeong Ho Choi , 정우혁 Woo Hyeok Jeong , 김홍수 Hong Su Kim , 이상진 Sang Jin Yi , 김영일 Young Il Kim

DOI: Vol.29(No.1) 107-113, 2013

The major tributaries in Sapgyo-reservoir watershed at Chungcheongnam-do were monitored for flowrate and water quality in order to analyze the characteristics of watershed and to prepare for implementation of total maximum daily load According to the analytical results of flowrate and water quality monitoring data of sixteen tributaries the tributaries with the value of flowrate over 0.5m³/s were 62.5% among the monitored tributaries and value of flowrate in the Cheonancheon Namwoncheon Shinyangcheon except Gokgyocheon Muhancheon Sapgyocheon was relatively greater than the other tributaries. However 37.5% of the tributaries were exceeded the water quality standards of Sapgyocheon sub-basin(BOD_5 5mg/L and/or below) and the concentration of water pollutants regardless of water quality parameters in Cheonancheon Maogokcheon Oncheoncheon including Gokgyocheon located in Gokgyocheon catchment were relatively higher than the other tributaries. The tributaries for improving the water quality according to stream grouping method based on the results of flowrate and water quality monitoring data were selected. In the Sapgyo-reservoir watershed the tributaries for improving water quality which has a large flowrate and a high concentration of water pollutants were selected at Cheonancheon Gokgyocheon Maegokcheon Namwoncheon Oncheoncheon. The various water quality improving plans for those tributaries in accordance with the reduction of point source pollution by population and livestock should be established and implemented.

Flowrate and water quality, Sapgyo-reservoir watershed, Stream grouping method, Total maximum daily load, Tributary

공동수 Dongsoo Kong , 김진영 Jin Young Kim , 손세환 Se Hwan Son , 오민우 Min Woo Oh , 최아름 Ah Reum Choi , 변명섭 Myeong Seop Byeon

DOI: Vol.29(No.1) 114-126, 2013

The purpose of this study was to develop a Korean thermality index based on the distribution patterns of benthic macroinvertebrates according to altitude and latitude. Analyzing seasonal data (4,583 sampling units) surveyed and collected during 2007~2011 at 846 sites in South Korea we estimated thermal valency thermal value and indicator weight value of 208 species. Among them 40 species in 6 orders (Decapoda 1 species Collembola I species Ephemeroptera 5 species Plecoptera 17 species Diptera 3 species Trichoptera 13 species) were selected as the candidate indicator species sensitive and vulnerable to warmth along with climate change. KTI and Benthic macroinvertebrate index were tested at three clean streams (Hangye stream Buk stream and Bangtae stream). KTI showed significant differences according to altitude and water temperature whereas the saprobity index BMI showed little differences. This result means that KTI can be applicable to assess the impact of water temperature independently of organic of pollutants.

Altitude, Benthic macroinvertebrates, Climate change, Indicator species, KTI

조일형 Il Hyoung Cho , 이시진 Si Jin Lee , 김지태 Ji Tae Kim

DOI: Vol.29(No.1) 127-137, 2013

Reuse of wastewater will intensify in the coming decades due to water shortage the change of climatic conditions the need for industrial and agricultural use and the necessity of improving health and environmental conditions for the growing population. This paper considers (a) the status and trends of wastewater reuse and reclamation in the world (b) case studies of wastewater reuse projects (c) analysis of technology level (d) forecast of global market and (e) the future views and directions in development of wastewater reuse technologies. Based on the available documented literature this paper provides a review assessment of the current status of the wastewater treatment processes including potential applications for reuse. Key challenges for both wastewater treatment and reuse are also discussed in the paper and include recommendations e.g. cost effluent water quality energy use and technical solutions for future developments.

Direction, Forecast, Market, Reclamation, Reuse, Wastewater