박형석 Hyung Seok Park , 정세웅 Se Woong Chung , 윤성완 Sung Wan Yoon , 류인구 In Gu Ryu

DOI: Vol.27(No.6) 743-753, 2011

One of the most important water management issues of Soyang Reservoir, located in North Han River in Korea, is a long term discharge of turbid water to downstream during flood season. Installation of a selective withdrawal structure (SWS) is planned by the reservoir management institute as a control measure of outflow water quality and associated negative impacts on downstream water use and ecosystem. The objective of the study was to explore the effectiveness of the SWS on the control of outflow turbidity under two different hydrological years; one for normal flood year and another for extreme flood year. A two-dimensional (2D), laterally averaged hydrodynamic and water quality model (CE-QUAL-W2) was set up and calibrated for the reservoir and used to evaluate the performance of the proposed SWS. The results revealed that the SWS can be an effective method when the θ value, the ratio between the amount of turbid water that containing suspended sediment (SS) greater than 25 mg/L and the total storage of the reservoir, is 0.59 during the normal flood year. However, the effectiveness of the SWS could be marginal or negative in the extreme flood year when θ was 0.83. The results imply that the SWS is an effective alternative for the control of turbid water for moderate flood events, but not a sufficient measure for large flood events that are expected to happen more often in the future because of climate change.

CE-QUAL-W2, Reservoir operation, Selective withdrawal structure, Soyang Reservoir, Turbidity flow

안조환 Jo Hwan Ahn , Robert Seviour

DOI: Vol.27(No.6) 754-759, 2011

A sequencing batch reactor (SBR) was operated under different pH conditions to better understand the influence of pH to granulation in enhanced biological phosphorus removal systems. Granules from the SBR were also investigated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Considerable decreases in the amount of phosphorus released per substrate provided under anaerobic conditions and the content of biomass polyphosphate under aerobic conditions were observed when pH was changed from 7.5 to 7.0, followed by 6.5. Aerobic granulation was also observed at pH 7.0. A number of bacteria with the typical morphological traits of tetrad-forming organisms (TFOs) were observed at pH 7.0, including large members of cluster. Filamentous bacteria were also there in large numbers. The occurrence and growth of granules were further enhanced at pH 6.5. A SEM analysis showed that the aerobic granules had a compact microbial structure with shaperical shape and morphologically consisted of aggregates of small coccoid bacteria and filamentous bacteria encapsulated by extracellular polymeric substance. The main material ions identified by EDX moreover revealed that the structural materials for polyphosphate in the granules include phosphorus, potassium and calcium. Therefore, these results strongly suggested that PAOs are a dominant population in the microbial community of the aerobic granules.

EBPR, Granulation, PAOs, SEM-EDX, TFOs

오민우 Min Woo Oh , 이옥민 Ok Min Lee , 송호복 Ho Bok Song , 박선진 Sun Jin Park , 송미영 Mee Young Song , 공동수 Dong Soo Kong

DOI: Vol.27(No.6) 760-768, 2011

Jinwi Stream is considerably polluted. The urban development in a Jinwi Stream basin can make state of aquatic ecosystem worse. However, researches for aquatic ecosystems in Jinwi Stream are insufficient. In this study, biotic indices of periphytic diatoms (DAIpo and TDI), benthic macroinvertebrates (EPT, KSI and ESB) and fish (IBI) were compared with the annual water quality data. Benthic macroinvertebrates indices showed highly significant correlations with concentrations of organic materials and nutrients, while DAIpo, TDI and IBI showed low correlations with them. In particular, ESB can be considered as an useful indicator that reflects the degree of diversity and abundance of biotic community as well as water quality. In polluted and disturbed streams as Jinwi Stream, DAIpo, TDI and IBI appeared to be not available for evaluating and discriminating the water quality, although they have been known as good indices in general streams.

Benthic macroinvertebrates, Biotic index, Fish, Jinwi Stream, Periphytic diatoms

이한샘 Han Saem Lee , 이상일 Sang Il Lee , 윤주환 Zu Whan Yun

DOI: Vol.27(No.6) 769-775, 2011

An experimental study of biofilm nitritation system for high-strength ammonium wastewater has been carried out to examine the temperature effect on different organic and solid concentration. Operating temperature varied from 35°C to 15°C. The influent N concentration of identical three reactors was adjusted to about 300 mg NH4-N/L. A control unit fed with a synthetic wastewater, while the others were fed with reject water which is consisted of the supernatant of both digester and thickener. The results indicated that nitrite accumulation was stable in temperature range of 35°C to 25°C. However, nitritation was significantly reduced at below 20°C. Free ammonia (FA) and free nitrous acid (FNA) were major inhibitors to the nitrite oxidizer for nitrite accumulation in lower temperature. From the estimation of temperature coefficient (θ) of biofilm and suspended nitritation system, biofilm nitritation system could absorb the negative temperature effect compared with suspended nitritation system.

Biofilm, Nitritation, Reject water, Temperature effect

임지혁 Ji Hyeok Im , 손세환 Se Hwan Son , 김진영 Jin Young Kim , 오민우 Min Woo Oh , 남귀숙 Gui Sook Nam , 송영희 Young Hee Song , 이옥민 Ok Min Lee , 공동수 Dong Soo Kong

DOI: Vol.27(No.6) 776-783, 2011

In a natural water body, a useful ecotechnology to reduce standing crops of phytoplankton is to strengthen the top-down force of zooplankton. However, the predation of fish for zooplankton can make the force weak. This study was conducted to find out the effect of fish on the grazing pressure of zooplankton in the mesocosms established in a eutrophic stream (Kyongan Stream) from October to November in 2010. In the corral with fish, chlorophyll a concentration increased, and a small size cladoceran Bosmina longirostris was dominant. In the corral without fish, chlorophyll a concentration decreased along with the domination of a large cladoceran Daphnia galeata and a large copepod Eudiaptomus japonicus. The size-selective predation of fish appeared to miniaturize the zooplankton community, to narrow their food-size spectrum, and to weaken the top-down force.

Biomanipulation, Ecotechnology, Kyongan stream, Top-down force

신민환 Min Hwan Shin , 최재완 Jae Wan Choi , 최용훈 Young Hun Choi , 박운지 Woon Ji Park , 원철희 Chul Hee Won , 신동석 Dong Suk Shin , 임경재 Kyoung Jae Lim , 최중대 Joong Dae Choi

DOI: Vol.27(No.6) 784-793, 2011

Activities on golf courses are believed to contribute to the degradation of water quality in receiving waters due to the excessive use of farm chemicals including fertilizers and pesticides. The objective of this study was to collect basic data that could explain the characteristics of non-point source (NPS) pollution discharged from a golf course. Twenty seven water quality monitoring was conducted at a golf course during the rainy season of 2008 and 2009. The results indicated that the ranges of the Event Mean Concentration (EMC) at the golf course were BOD5 1.8~11.3 (ave. 5.6) mg/L, CODMn 19.2~51.4 (ave. 39.6) mg/L, TOC 11.0~31.0 (ave. 16.8) mg/L, TN 1.545~16.098 (ave. 5.623) mg/L, TP 0.230~4.528 (ave. 1.525) mg/L, and SS 2.2~57.3 (ave. 10.1) mg/L. The unit loads of the golf course estimated were BOD5 3.35 kg/km2/day, SS 6.43 kg/km2/day, CODMn 30.00 kg/km2/day, TN 4.04 kg/km2/day, TP 1.14 kg/km2/day, and TOC 12.16 kg/km2/day. Golf courses are currently classified as a grass field in which the unit loads are different from golf courses. Therefore, it was recommended that golf courses need to be separated from the grass field when the surveys and modelings for Total Maximum Daily Load (TMDL) development and the evaluation of TMDL implementation were performed.

Event Mean Concentration (EMC), Golf course, Non-point source (NPS), Runoff, Total Maximum Daily Load (TMDL), Unit Loads

박성천 Sung Chun Park , 진영훈 Young Hoon Jin , 노경범 Kyong Bum Roh , 김종오 Jong O Kim , 유호규 Ho Gyu Yu

DOI: Vol.27(No.6) 794-803, 2011

Self Organizing Map (SOM) was applied for pattern classification of hydrological and water quality data measured at Jangseong Reservoir on a monthly basis. The primary objective of the present study is to understand better data characteristics and relationship between the data. For the purpose, two SOMs were configured by a methodologically systematic approach with appropriate methods for data transformation, determination of map size and side lengths of the map. The SOMs constructed at the respective measurement stations for water quality data (JSD1 and JSD2) commonly classified the respective datasets into five clusters by Davies-Bouldin Index (DBI). The trained SOMs were fine-tuned by Ward`s method of a hierarchical cluster analysis. On the one hand, the patterns with high values of standardized reference vectors for hydrological variables revealed the high possibility of eutrophication by TN or TP in the reservoir, in general. On the other hand, the clusters with low values of standardized reference vectors for hydrological variables showed the patterns with high COD concentration. In particular, Clsuter1 at JSD1 and Cluster5 at JSD2 represented the worst condition of water quality with high reference vectors for rainfall and storage in the reservoir. Consequently, SOM is applicable to identify the patterns of potential eutrophication in reservoirs according to the better understanding of data characteristics and their relationship.

Data characteristics, Hydrological data, Pattern classification, Reservoir, Self Organizing Map (SOM), Water quality

남선화 Sun Hwa Nam , 곽진일 Jin Il Kwak , 윤성지 Sung Ji Yoon , 정승우 Seung Woo Jeong , 안윤주 Youn Joo An

DOI: Vol.27(No.6) 804-812, 2011

To prevent the overflow of various harmful chemicals, it is necessary to modify the chemical management system with an expansion to institutionally regulated substances. This modification should be preceded by selection of the priority chemicals, with a diverse chemical ranking system (CRS) applied to select the chemicals in developed countries. In Korea, a systematic CRS was used in a project related to soil and groundwater, however, it is inadequate to compare soil and groundwater CRS to that of surfacewater. In this study, a priority chemical ranking system for surfacewater was proposed through the analysis of international and domestic CRS cases. This was then applied to 161 chemicals to derive the priority list of harmful chemicals. As a result, Chemical RAnking of surFacewater polluTants (CRAFT) is presented for the protection of human health and the aquatic ecosystem from surfacewater pollutants. The components of CRAFT are the human health toxicity, aquatic ecosystem toxicity and reliability assessment factors. Three lists were derived from the 161 priority harmful chemicals for the protection of human health, aquatic ecosystem or both. It is expected that this result can be useful to prioritize harmful chemicals for the protection of human health and the aquatic ecosystem from Korean surfacewater.

Aquatic ecosystem, Chemical ranking of surfacewater pollutants (CRAFT), Chemical ranking system (CRS), Human health, Surfacewater

최창희 Chang Hee Choi , 남궁규철 Kyucheol Namkung , 윤종우 Jong Woo Youn , 이채영 Chae Young Lee

DOI: Vol.27(No.6) 813-821, 2011

While various aspects affect river water quality, reduction of water flow rate during dry seasons is one of the most significant factors causing severe water pollution in river water environment. The aim of this study is to investigate the feasibility of applying a physicochemical method (sand filtration+ozonation) for improving river water quality within a short period. The parameters analyzed and assessed were CODcr, BOD, SS and color. The source river water had a severe pollution level showing COD 8.8~17.2 mg/L (ave. 11.9 mg/L), BOD 4.8~13.3 mg/L (ave. 8.3 mg/L), SS 9.0~22.1 mg/L (ave. 12.8 mg/L) and color 34.4~77.1degree (ave. 56.5degree) during the experimental periods. The variation trends showed a relatively low correlation between BOD and COD and between color and COD, while SS showed very low correlation with other parameters. The combined process of sand filtration and ozonation showed averaged removal efficiency of COD 37.2%, BOD 48.4%, SS 60.1% and colority 45.1%, respectively. The marked change of BOD level from 8.3 mg/L to 4.3 mg/L under the experimental conditions in this study implied the improvement of class V to class III set by the river water quality standard in Korea.

COD, Color, Ozonation, River water quality, SS

노경범 Kyong Bum Roh , 박성천 Sung Chun Park , 진영훈 Young Hoon Jin , 박명옥 Myoung Ok Park

DOI: Vol.27(No.6) 822-829, 2011

The purpose of the present study is to estimate the ecological instream flow for conservation and restoration of fish habitat in running water ecosystem which has very important status for stream environment. Estimation of the ecological instream flow in the present study was carried out by application of a two-dimensional depth averaged model of river hydrodynamics, River2D model. It can model fish habitat in natural streams and rivers and assess the quality of physical habitat accoriding to the species preferences for habitat suitability. Zacco platypus and Zacco temmincki were selected as target fish species in the study area of the Seomjin river. The Habitat Suitability Criteria (HSC) developed by Sung et al. (2005) were used for target fish species, life stages and habitat conditions in the study. Weighted usable area (WUA) was computed by the River2D model considering preferences of target fish species for velocity, depth, and channel substrate. The result revealed that the ecological instream flow of 10.0 m3/s is needed to maintain the target fish habitat at each life stage in the river.

Ecological Instream Flow, Instream Flow Incremental Methodology (IFIM), River2D, Zacco platypus, Zacco temmincki

손태석 Tae Seok Shon , 이규열 Kyu Yeol Lee , 임태효 Tae Hyo Im , 신현석 Hyun Suk Shin

DOI: Vol.27(No.6) 830-840, 2011

Climate change has been settled as pending issues to consider water resources and environment all over the world, however, scientific and quantitative assessment methods of climate change have never been standardized. When South Korea headed toward water deficiency nation, the study is not only required analysis of atmospheric or hydrologic factors, but also demanded analysis of correlation with water quality environment factors to gain management policies about climate change. Therefore, this study explored appropriate monthly rainfall elasticity in chosen 41 unit watersheds in Nak-dong river which is the biggest river in Korea and applied monitored discharge data in 2004 to 2009 with monthly rainfall using Thiessen method. Each unit watershed drew elasticity between water temperature and water quality factors such as BOD, COD, SS, T-N, and T-P. Moreover, this study performed non-linear correlation analysis with monitored discharge data. Based on results of analysis, this is first steps of climate change analysis using long-term monitoring to develop basic data by Nak-dong river Environmental Research Center (Ministry of Environment) and to draw quantitative results for reliable forecasting. Secondary, the results considered characteristic of air temperature and rainfall in each unit watershed so that the study has significance its various statistical applications. Finally, this study stands for developing comparable data through "The 4 major river restoration" project by Korea government before and after which cause water quality and water environment changes.

Climate change, Elasticity, Water temperature, Water quality

주진걸 Jing Gul Joo , 유도근 Do Guen Yoo , 김중훈 Joong Hoon Kim

DOI: Vol.27(No.6) 841-847, 2011

In this study, a method to determine the design capacities of nonpoint source (NPS) pollutant treatment facilities in urban areas was suggested. A facility capacity to treat 80 percent of total SS discharge was estimated by 2-year rainfall-runoff-build-up and wash-off simulation at Goonja drainage district in Seoul. For wash-off simulation, four wash-off models (EMC, RC, EXP, and Joo model) were used. As the results, 80 percent of total SS discharge could be treated with only 7.7~31.4% facility capacity of peak flow. The suggested method and results will provide a guideline to determine design capacities of NPS pollutant treatment facility in urban areas.

Long-term simulation, Non-point source pollutant, SWMM, Treatment

원철희 Chul Hee Won , 신민환 Min Hwan Shin , 최용훈 Yong Hun Choi , 신재영 Jae Young Shin , 박운지 Woon Ji Park , 최중대 Joong Dae Choi

DOI: Vol.27(No.6) 848-854, 2011

The objective of this research was to experimentally test the effect of rice straw mats on the reduction of runoff, sediment and discharge under a laboratory scale with different rainfall intensity and slopes. We used the small runoff plots of 1 m × 1 m × 0.65 m (L×W×H) in size were filled with loamy sand. Experimental treatments were bare (control), rice straw mats+PAM(SP), rice straw mats+PAM+sawdust(SPS) and rice straw mats+PAM+rice husks(SPR); slope of 10% or 20%; and rainfall intensity of 30 or 60 mm/hr. Runoff volume and coefficient from covered plots were significantly lower than those from control plots. Under the 30 mm/hr and 10% simulations, average runoff coefficient of covered plots decreased more than 92%. Under 60 mm/hr and 20% simulations, the ratios were between 39.8~58.1%. Under the condition of 30 mm/hr rainfall and 10% slope, sediment discharge from covered plots was practically zero. And at 20% plots, sediment reduction ratio was more than 95%. Under the condition of 60 mm/hr rainfall, sediment reduction ratio of 10 and 20% plots ranged between 86.3~95.3% and between 79.8~86.5%, respectively. The differences in initial runoff time, runoff and sediment discharge among different cover materials were not significant. Rainfall intensity showed higher impact on initial runoff time, runoff, and sediment discharge than slope. It was also shown that even if runoff reduction by surface cover were low, sediment discharge reduction could be very significant and contribute to improve the water quality of streams in sloping agricultural regions. It was concluded that the use of straw mat and PAM on sloping agricultural fields could reduce soil erosion and muddy runoff significantly and help improve the water quality and aquatic ecosystem in receiving waters.

Rainfall simulation, Rice straw mats cover, Runoff, Sediment

김백호 Baik Ho Kim , 박혜진 Hye Jin Park , 민한나 Han Na Min , 공동수 Dong Su Kong , 황순진 Soon Jin Hwang

DOI: Vol.27(No.6) 855-861, 2011

Short-term effects of current velocity and turbid water on the benthic diatom community and water quality were examined in artificial channel (20×200×10 cm) with two different experiments. The first and second experiments were consisted of different current velocities such as 1 L/min., and 1, 3, and 6 L/min., respectively. The concentration of turbid water is prepared with loess and fixed at 10 and 20 times of the turbidity of control inflow (10 NTU, LTW), respectively. At experiment 1 (EXP-1), introduction of turbid water increased dissolved oxygen, electric conductivity, pH and turbidity, but there were no differences between low- (100 NTU, MTW) and high-turbid water (200 NTU, HTW). However, experiment 2 (EXP-2) did not change any environmental parameters except dissolved total and inorganic nitrogen like EXP-1. MTW in EXP-1 strongly stimulated the growth of benthic diatom, while both MTW (150 NTU) and HTW (300 NTU) in EXP-2 did not increase or decrease the diatom abundance. Over the study, the dominant species was four, Aulacoseira ambigua, Cyclotella stelligera, Aulacoseira granulata and Achnanthes minutissima. In EXP-1, two highest species in abundance, A. ambigua and A. granulata were highly grown in MTW, while Achnanthes minutissima high in HTW adversely. These results indicate that the introduction of turbid water can play an important role in the shift of water quality and benthic diatom community in stream ecosystem, especially inflow of soil water in low current velocity.

Artificial channel, Benthic diatom, Current, Turbid water, Water quality

어성욱 Seong Wook Oa

DOI: Vol.27(No.6) 862-867, 2011

Pozzolanic-based stabilization/solidification (S/S) is an effective and economic remediation technology to immobilize heavy metals in contaminated soils. In this study, quick lime (CaO) was used to immobilize cadmium and zinc present in waste mine contaminated clayey sand soils. Addition of 5% quicklime to the contaminated soils effectively reduced heavy metal leachability after 2 bed volume operation below the drinking water regulatory limits. Lime addition was revealed to increase the immobilization for all heavy metals in tested pH ranges, so it could be an optimal choice for short-term remediation of heavy metal contaminated soil. The mass balances for these column tests show metal reduction of 92% for Cd and 87% for Zn of total resolved mass in case of 5% lime application.

Heavy metal pollution, Leaching test, Lime stabilization, Solidification

이경숙 Kyoung Sook Lee , 정재운 Jae Woon Jung , 최동호 Dong Ho Choi , 윤광식 Kwang Sik Yoon , 최우정 Woo Jung Choi , 최수명 Soo Myung Choi , 임상선 Sang Sun Lim , 박하나 Ha Na Park , 임병진 Byung Jin Lim , 최강원 Gang Won Choi

DOI: Vol.27(No.6) 868-876, 2011

A five-year field monitoring was conducted to monitor characteristics of suspended solid (SS) export from paddy fields. The observed EMCs of SS ranged 1.2~517 mg/L (avg. 52.1 mg/L) during storm period. The concentration of SS during non-storm period were 1.1~349.5 mg/L (avg. 36.1 mg/L). Monthly load of SS was high during summer when rainfall amount was high. The load was higher than that of May when tillage effect is expected. There was no significant relationship between SS EMCs and rainfall or drainage amount. However, effects of rainfall and drainage were found to be significant for event load of SS. But, there was no apparent relationship between rainfall amount of cropping period and load of SS for that period. The observed SS load was 164.8~456.0 kg/ha (avg. 301.2 kg/ha) and mostly occurred during storm period. This study results also suggested that SS load estimation by USLE equation for paddy field could be overestimated, if not carefully handled. Monitoring studies for various climate, soil, and agricultural management are required to get better scope of SS export from paddy fields.

Nonpoint source pollution, Paddy field, SS, Water quality

강동한 Dong Han Kang , 장영호 Young Ho Jang , 김종수 Jong Su Kim , 김극태 Keug Tae Kim

DOI: Vol.27(No.6) 877-884, 2011

In this paper, the removal characteristics of dissolved organic carbon (DOCs) by micro bubble ozonation process and O3/UV process were comparatively studied. In the point of DOC removing reaction coefficient, micro bubble ozonation system and O3/UV process had not significant difference, 0.0120 sec-1 and 0.0141 sec-1. Therefore micro bubble ozonation process is more suitable for tertiary treatment of sewage in the point of installation and maintenance cost-reducing. The optimum ozone injection rate was 2.0 g O3/g DOC and HRT was 3 min for the micro bubble ozonation process. The removal efficiency of DOC and SUVA in micro bubble ozonation system was 32.8% and 58.3% respective. Biological aerated filter (BAF) process was installed to remove soluble organic material increased by micro bubble ozonation system. And the effluent BOD of BAF was below 1.0 mg/L. In the view of cost-effectiveness, O3/BAF process was more profitable than O3/UV/BAF process for tertiary treatment of sewage. In order to nitrify ammonia in the BAF process completely, NH4+-N concentration in the influent water of BAF should be designed considering low water temperature in the winter season.

Advanced oxidation process (AOP), Biological aerated filter (BAF), Dissolved organic carbon (DOC), SUVA, Wastewater

황하선 Ha Sun Hwang , 박배경 Bae Kyung Park , 김용석 Yong Seok Kim , 박기중 Ki Jung Park , 천세억 Se Uk Cheon , 이성준 Sung Jun Lee

DOI: Vol.27(No.6) 885-895, 2011

The purpose of this study was evaluated on achievement of the Target water quality (TWQ) with Load Duration Curve (LDC) as well as materials collected through the implementation of Total Maximum Daily Load (TMDL), targeting 41 unit watersheds in the Nakdong River Basin in korea, and examines the adequacy of the LDC method to evaluate the TWQ by comparing methods through current regulations. It aims to provide basic materials for TMDL development in Korea. This determination resulted from the fact that the measured data placed on the LDC mean that they are beyond TWQ in a certain condition of water flow when actually measured load values were displayed in a form of LDC. In addition to water quality surveys, it is considered that information on the level of damage in a water body by water flow grade can be utilized as a basic material to identify compliance with the total admitted quantity, and establish rational plans to improve water quality. This information helps in the identification of the degree of damage in water quality according to water flow.

Implementation, Load duration curve, Target water quality, Total Maximum Daily Load (TMDL)

김수연 Soo Yeon Kim , 최예슬 Ye Seul Choi , 김동수 Dong Su Kim

DOI: Vol.27(No.6) 896-904, 2011

The features of the capture reaction of CO2 by ammonia solution have been investigated along with the effect of temperature on the reaction based upon computer program-utilizing calculation and thermodynamic estimation. The stable region of CO32- was observed to increase with temperature and the change of the stable region of CO32- with temperature was greater than the temperature variation of the stable region of other carbonate species. The distribution diagram for NH4+-NH3 system was constructed and the rise of temperature resulted in the decrease of the stability of NH4+ ion, which was thought to be due to the endothermic nature of its acidic dissociation. Considering the introduction of Ca2+ ion in the carbon capture reaction by NH4+, the temperature was observed to be important in the determination of the order of reaction between carbonate ion and these cations. The removal process of CO2 gas by ammonia solution was presumed to occur in open system and the temperature variations of the concentration of carbonate system species along with their total concentration were calculated for the proper control and design of the real process.

Ammonia solution, CO2 capture, Temperature, Thermodynamic estimation

박지형 Ji Hyoung Park , 손수민 Su Min Sohn , 류덕희 Doug Hee Rhew

DOI: Vol.27(No.6) 905-913, 2011

This study was conducted to characterize the discharge feature of pollutant load from the upper and lower watershed influencing on the water quality of South Han River using the empirical equation and Factor Analysis. The results of regression analysis between flow rate and pollutant load were as follows. In the streams of the upper watershed of South Han river, BOD5 and CODMn were increased as the flow rate was increased. Also, steep increases in SS and TP were observed with positive correlation with the flow rate while change in TN was slightly shown. On the other hand, in the streams of the lower watershed of South Han river, BOD5 was negatively correlated with the flow rate, being decreased with the increase in the flow rate. However, changes in CODMn, TN, SS, and TP showed a similar trend with those observed in the upper watershed. With Factor Analysis of the water quality and various components, it was appeared that the flow rate, SS, and TP were significantly correlated each other and they were indicated as the principal component influencing on water quality in the streams of the upper watershed. In contrast, BOD5, CODMn, and TOC were significantly correlated each other and they were included as the principal pollution component of the streams in the lower watershed. From these results, it was conclusive that the upper watershed of South Han River was mainly affected by non point source pollutants while the lower watershed was influenced by point source pollutants from the developed areas.

Factor analysis, Non point source pollutants, Point source pollutants, South Han River

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

DOI: Vol.27(No.6) 914-925, 2011

The variation of streamflow is regarded as one of the most influential factors on the fluctuation of water quality in the stream. The characteristics of the variation should be taken into account in the plans for the management of Total Maximum Daily Loads (TMDLs). This study analysed and characterized spatial distribution and temporal variation of streamflow at each unit watershed in Guem-river basin. For the analysis of the distribution of streamflow, the type and the extent of the distribution were investigated for the unit watershed. For the analysis of the variation, short and long term changes of streamflow were examined. The result showed that most of the distributions were not log-normalized and the extent of variation tends to be greater at the unit watershed placed on the tributaries in the basin. A kind of margin could be granted to the unit watershed involving high variations so as to establish the water quality goal and load allotment more reasonably and effectively in view of whole waterbody.

Spatial distribution, Streamflow, Temporal variation, Total Maximum Daily Loads (TMDLs), Unit watershed

이정열 Jung Yeol Lee , Xue Jiao Chen , 민경석 Kyung Sok Min

DOI: Vol.27(No.6) 926-931, 2011

Among various techniques for hydrogen production from organic wastewater, a dark fermentation is considered to be the most feasible process due to the rapid hydrogen production rate. However, the main drawback of it is the low hydrogen production yield due to intermediate products such as organic acids. To improve the hydrogen production yield, a co-culture system of dark and photo fermentation bacteria was applied to this research. The maximum specific growth rate of R. sphaeroides was determined to be 2.93 h-1 when acetic acid was used as a carbon source. It was quite high compared to that of using a mixture of volatile fatty acids (VFAs). Acetic acid was the most attractive to the cell growth of R. sphaeroides, however, not less efficient in the hydrogen production. In the co-culture system with glucose, hydrogen could be steadily produced without any lag-phase. There were distinguishable inflection points in the accumulation of hydrogen production graph that resulted from the dynamic production of VFAs or consumption of it by the interaction between the dark and photo fermentation bacteria. Lastly, the hydrogen production rate of a repeated fed-batch run was 15.9 mL-H2/L/h, which was achievable in the sustainable hydrogen production.

Bio-hydrogen, Clostridium butyricum, Co-culture, Dark fermentation, Photo fermentation, Rhodobacter sphaeroides

김건하 Geon Ha Kim

DOI: Vol.27(No.6) 932-937, 2011

Main objectives of this paper were; firstly, to explain impacts of suspended solid in the water body on the relationship between water quantity and water quality; secondly, study on the inter-relationship between organic materials, nutrients, pathogens, and suspended solids considering eco-friendly water resources. Relationship between water quality and water quantity is not easy to understand as it includes physicochemical-biological reactions and diffuse pollutions. Especially, suspended solid makes water resource management difficult. Eroded soil in the upper land transported to the downstream by water flows carrying biological and physicochemical information and sedimented in the downstream. As sediment scoured under high flow condition and environmental change, suspended solid and sediment should be emphasized for understanding the inter-relationship between water quality and water quantity. Knowledge gaps between known monitored data and management of suspended solid were identified as well for future study.

Integrated watershed management, Sediment, Suspended solid, Water quality, Water quantity, Water resources