백종석 Jongseok Back , 김백중 Baekjoong Kim , 이상진 Sangjin Lee , 김형산 Hyungsan Kim

DOI:10.15681/KSWE.2017.33.6.617 Vol.33(No.6) 617-625, 2017

Both domestic and overseas urban drainage systems have been actively researched to solve the problems of urban flash floods and the flood damage that is caused by local downpours. Recent urban planning has been designed to better manage the floods of decentralized rainfall-management systems, and the installation of green infrastructure and low-impact development (LID) facilities at national ministries has been recommended. In this study, we use the EPA SWMM model to construct a decentralized rainfall-management network for each small watershed, and we analyze the effect of the drainage-capacity improvement from the installation of the LID technologies in vulnerable areas that replaces the network-expansion process. In the design of the existing urban piping systems, it is common to increase the pipe size due to the increment of the impervious area, the steep terrain, and the sensitive entrance-ramp junction; however, the installation of green infrastructure and LID facilities will be sufficient for the construction of a safe urban drainage system. The applications of LID facilities and green infrastructure in urban areas can positively affect the recovery of the corresponding water cycles to a healthy standard, and it is expected that further research will occur in the future.

Decentralized Rainfall Management, Drainage Capacity, EPA SWMM, LID, Sewer Network

공동수 Dongsoo Kong , 손세환 Se-hwan Son , 김진영 Jin-young Kim , 김필재 Piljae Kim , 권용주 Yongju Kwon , 김정우 Jungwoo Kim , 김예지 Ye Ji Kim , 민정기 Jeong Ki Min , 김아름 Ah Reum Kim

DOI:10.15681/KSWE.2017.33.6.626 Vol.33(No.6) 626-639, 2017

Based on an ecological monitoring in a Korean stream (Gapyeong), Habitat Suitability Index (HSI) of nine fish species was developed for three physical habitat factors : current velocity, water depth and substrate. The species were chosen based on their abundance and frequency in the fish community of the Gapyeong stream. The Weibull model was used as the probability density function to analyze the distribution and number of each fish species according to the three identified physical factors, which showed good results. This HSI equation has advantages because it statistically expresses habitat preferences of fish species simply and clearly. From that, we can quantitatively deduce the central tendency and variation of environmental factors for fish distribution. The selected fish species showed different preferences for each habitat factor respectively. Although there are some exceptions, the distribution and abundance of individual species of nektonic fish (Zacco koreanus, Zacco platypus, Microphysogobio longidorsalis and Pungtungia herzi) were positively skewed to deep water and fine substrate while riffle-benthic fish (Koreocobitis rotundicaudata and Coreoleuciscus splendidus) were normally distributed at the shallow and coarse substrate zone. It seems that the species showing the positively skewed distribution to the current, Z. koreanus, Z. platypus, M. longidorsalis and P. herzi have adapted themselves to the fast current and have expanded their niche.

Environmental flow, Fish, Gapyeong stream, Habitat Suitability Index

김소래 Sorae Kim , 김상민 Sang Min Kim

DOI:10.15681/KSWE.2017.33.6.640 Vol.33(No.6) 640-649, 2017

The purpose of this study is the analysis of the water quality spatial characteristics for the main stream of Nakdong River in consideration of the tributary inflow. The flow and water quality (BOD, TOC, TP) data for 32 monitoring stations located in the main stream and the tributaries of Nakdong River were collected from 2003 to 2016. From the results of the flow and water quality analyses for each site, a status map of the flow and the water quality for Nakdong River was produced. The water quality of each river section was classified according to seven river-environment standards. The water quality changes in the main stream before and after the confluence were analyzed spatially. As a result, the water quality of Kumho River, in particular the Kumho B to Kumho C section, is the worst among the tributaries. In addition, the water quality grades of the lower streams such as Nam River and Miryang are worse than that of the upper streams of the Nakdong River. In the case of the main stream, the water quality grades of the sections between the Wicheon and Nam River confluences and the section from Nakbon L to Nakbon N are relatively poor.

Nakdong River, Spatial Analysis, Tributary, Water Quality

박진환 Jinhwan Park , 강태우 Taewoo Kang , 한성욱 Sungwook Han , 백승권 Seunggwon Baek , 강태구 Teagu Kang , 유제철 Jechul Yoo , 김영석 Youngsuk Kim

DOI:10.15681/KSWE.2017.33.6.650 Vol.33(No.6) 650-660, 2017

In this study, pollutant emission characteristics by water damage period analyzed 11 items (water temperature, pH, DO, EC, BOD, COD, TOC, SS, T-N, T-P and flow) with load duration curve, time series load curve and factor analysis for three years (2014-2016). Load duration curve is applied to judge the level of impaired waterbody and estimate impaired level by pollutants such as BOD and T-P in this study depending on variation of stream flow. Water quality standard exceeded the flow of mid-range and low-range by flow condition evaluation using load duration curve. This watershed was influenced by point source more than non-point source. Cumulative excess rate of BOD and T-P kept water quality standard for all seasons (spring, summer, autumn and winter) except BOD 59% in spring. Water quality changes were influenced by pollutants of basic environmental treatment facilities and agricultural areas during spring and summer. Results of factor analysis were classified commonly first factor (BOD, COD, and TOC) and second factor (flow, water temperature and SS). Therefore, effects of artificial pollutants and maintenance water must be controlled seasonally and reduced relative to water damage caused by point pollution sources with effluent standard strengthened in the target watershed.

Factor Analysis, Jiseok Stream Watershed, Load Duration Curve (LDC), Principal Component Analysis, Time Series Load Curve

박민혜 Min-hye Park , 박선화 Sunhwa Park , 김현구 Hyun-koo Kim , 황종연 Jong-yeon Hwang , 김태승 Tae-seung Kim , 정현미 Hyen Mi Chung , 조홍래 Hong-lae Cho , 이태환 Taehwan Lee , 구본경 Bhon K. Koo , 박윤희 Park Yun Hee

DOI:10.15681/KSWE.2017.33.6.661 Vol.33(No.6) 661-669, 2017

A distributed watershed model CAMEL (Chemicals, Agricultural Management and Erosion Losses) was applied to a small rural watershed where intensive livestock farming sites are located to estimate nitrate leaching rates from soil to groundwater. The model was calibrated against the stream flows, and T-N and NO₃-N concentrations were observed at the watershed outlet for three rainfall events in 2014. The simulation results showed good agreement with the observed stream flows (R² = 0.67~0.93), T-N concentrations (R² = 0.40~0.58) and NO₃-N concentrations (R² = 0.43~0.65). The estimated annual nitrate leaching rate of the watershed was 33.0 kg N/ha/yr. The contributing proportions of individual activities to the total nitrate leaching rate of the watershed were estimated for livestock farming, applications of chemical fertilizer, and manure. The simulation results showed that the highest contributor to the nitrate leaching rate of the watershed was chemical fertilizer applications. The simulation period was for one year only, however, and results may vary depending on different conditions. Gathering input data over a longer period of time and monitoring data for calibration is needed. When this has been accomplished, it is expected that this model can be applied to small rural watersheds for evaluating temporal and spatial variations of nitrogen transformations and transport processes.

distributed watershed model CAMEL, groundwater, mass balance, nitrate leaching

윤석제 Seok Jea Youn , 김헌년 Hun Nyun Kim , 김용진 Young Jin Kim , 임종권 Jong Kwon Im , 이은정 Eun Jeong Lee , 유순주 Soon Ju Yu

DOI:10.15681/KSWE.2017.33.6.670 Vol.33(No.6) 670-679, 2017

An experiment to study the effect of temperature, light, and dredging on release of nutrients downstream from Gongjicheon in the Uiam reservoir was carried out in the laboratory using sediments from different depths. At various water temperatures, dissolved total nitrogen was not released, but the average nutrient flux of dissolved total phosphorus was increased (0.034 at 15°C, 0.005 at 20°C, 0.154 at 25°C, 0.592 mg/㎡/d at 30°C). Dissolved total phosphorous was released in controlled darkness. In contrast, in controlled light, the concentrations of dissolved total phosphorous and dissolved total nitrogen in the overlying water steadily decreased during the study period (70 d), because they were continuously consumed by the growth of photosynthetic algae. However, there was no significant relationship between water nutrient concentration, nutrient release, and the depth of the sediment. We concluded that the dredging of sediment would not affect the nutrient release rate of the sediment, because there were no significant differences in the nutrient concentrations released from the sediment. When the sediment was removed from the surface to 20 cm in depth , the nutrients were not transferred to the water body, implying that the sediment removal had little effect on secondary pollution.

Benthic flux, Dredging, Light, Sediment, Temperature

손영규 Younggyu Son , 나승민 Seungmin Na , 임태효 Tae Hyo Im , 김상훈 Sang-hun Kim

DOI:10.15681/KSWE.2017.33.6.680 Vol.33(No.6) 680-688, 2017

Water quality monitoring for flow rates and BOD/COD/T-N/T-P/SS/TOC concentrations has been conducted in Nakdong river tributaries since 2011. In this study concentrations and loading rates of BOD, T-P, and TOC were analyzed to evaluate water quality monitoring stations using accumulated data at 206 tributary monitoring stations in Nakdong river 2012~2016. Average concentration ranges for 206 monitoring stations were 0.3~6.4 mg/L, 0.025~1.562 mg/L, and 0.6~10.7 mg/L for BOD, T-P, and TOC, respectively. Additionally, average loading rate ranges were 0.96~46,040 kg/d, 0.087~1,834 kg/d, and 1.51~80,425 kg/d for BOD, T-P, and TOC, respectively. Average concentration for BOD, T-P, and TOC at each monitoring station was evaluated using ambient water quality standards of rivers and water quality regulation level for medium-sized management areas. Average loading rate and specific loading rate (loading rate/drainage basin area) for BOD, T-P, and TOC at each monitoring station was considered to evaluate monitoring stations using suggested classification (BOD, TOC: -1, 1~10, 10~100, 100~1,000, and 1,000~ kg/d; T-P: -0.1. 0.1~1, 1~10, 10~100, and 100~ kg/d) Using results of this study, various water quality status maps were provided, and three evaluation methods were suggested to determine priority monitoring stations in Nakdong river for rational water quality control and tributaries basin management.

Loading rate, Nakdong river, Tributaries, Water quality, Water quality status maps

전소담 Sodam Jeon , 정성욱 Sungwook Choung , 한원식 Weon Shik Han , 장경순 Kyoung-soon Jang , 신우식 Woosik Shin , 황정환 Jeonghwan Hwang

DOI:10.15681/KSWE.2017.33.6.689 Vol.33(No.6) 689-695, 2017

This study was carried out to investigate the physicochemical and adsorptive characteristics of black carbon (BC) materials for cesium in case of severe nuclear accidents. The BC was prepared with a xylem of oak and pine trees incompletely combusted with different ramp rate and final temperature. Carbon (C), hydrogen (H) and oxygen (O) atomic ratios, BET, pore structure, and zeta potential were characterized for the produced BC. A low cesium concentration (C_w?10^-7 M) was used for sorption batch experiments. The H/C and O/C ratios of BC decreased with the increase of final temperature, which indicates a carbonization of the wood materials regardless of ramp rate and tree species. However, SEM images showed different pore structures depending on tree species such as steric and plate-like for oak-BC and pine-BC, respectively. The greatest sorption distribution coefficients of K_d,Cs?1,200~1,800 L kg^-1 were observed for the oak-BC produced at 400°C, while comparatively low K_d,Cs<100 L kg^-1 for pine-BC. In addition, the sorption capabilities of BC declined with the increase of combustion temperature up to 600°C, because high temperature destroyed surface functionalities with the rise of ash components in the BC. Therefore, the sorption processes of BC for radioactive cesium are predominantly controlled by final production temperature of BC as well as raw materials (e.g., tree species).

Black carbon, Nuclear Accident, Radioactive cesium, Sorption

공동수 Dongsoo Kong

DOI:10.15681/KSWE.2017.33.6.696 Vol.33(No.6) 696-714, 2017

Simple material budget models were developed to predict the spring season (March~May) water quality for a river-type reservoir Paldang, in the Republic of Korea. These models are available at mixed water bodies whose light intensity is negligible at the bottom. The calculated data from the models fit quite well with field data collected for 30 years, from 1988 to 2017. The apparent settling velocity of total phosphorus was estimated to be 110 m d^-1. The critical hydraulic load that determines the usability of phosphorus for algal production appeared to be about 2.0 m d^-1. When a hydraulic load was larger than the critical value, the concentrations of chlorophyll α (Chl.α), chemical oxygen demand (COD), and 5-day biochemical oxygen demand BOD in the reservoir water became insensitive to internal algal reactions. The model analysis showed that the allochthonous COD continued to increase while the allochthonous BOD slightly decreased after 1999. The decrease of allochthonous BOD is due to the expansion of sewage and wastewater treatment plants in the watershed. The increase of allochthonous COD seems to result from the increase in anthropogenic non-point sources as well as the increase in the discharge of natural organic matters due to climate change. Organic matter of algal origin continued to increase until the mid-2000s, but recently it has decreased as the phosphorus concentration has decreased. The COD and BOD of algal origin increased from 35% and 30% during 1988~1994 to 43% and 42% during 2000~2010, respectively, and then decreased to 25% and 29% during 2011~2017.

Eutrophication, Material budget modeling, Paldang, Phosphorous, River-type reservoir, Water quality

Franz Kevin F. Geronimo , 홍정선 Jungsun Hong , 김이형 Lee-Hyung Kim

DOI:10.15681/KSWE.2017.33.6.715 Vol.33(No.6) 715-721, 2017

Tree box filters, an example of bioretention systems, were compacted and versatile urban stormwater low impact development technique which allowed volume and water quality treatment performance to be adjusted based on the hydrologic, runoff quality and catchment characteristics. In this study, the overall performance of a 6 year-old tree box filter receiving parking lot stormwater runoff was evaluated. Hydrologic and hydraulic factors affecting the treatment performance of the tree box filter were also identified and investigated. Based on the results, the increase in rainfall depth caused decrease in hydrologic and hydraulic performance of the tree box filter including volume, average flow, and peak flow reduction (r = -0.53 to -0.59; p <0.01). TSS, organics, nutrients, and total and soluble heavy metals constituents were significantly reduced by the system through media filtration, adsorption, infiltration, and evapotranspiration mechanisms employed in the tree box filter (p <0.001). This significant pollutant reduction by the tree box filter was also found to have been caused by hydrologic and hydraulic factors including volume, average flow, peak flow, hydraulic retention time (HRT) and runoff duration. These findings were especially useful in applying similar tree box filter which may be designed by considering tree box filter surface area to catchment area of less than 1%.

Bioretention, Hydrologic and hydraulic factors, Low Impact Development, Tree box filter

어성욱 Seong Wook Oa

DOI:10.15681/KSWE.2017.33.6.722 Vol.33(No.6) 722-727, 2017

Livestock manure is known as the main cause of non-point pollutant in agricultural area. Pollutant reduction ratio of livestock manure recycling to fertilizers was measured in order to analyze the effect on water quality of Total Maximum Daily Load (TMDL) system in Korea. The reduction ratio has been applied by theoretical consideration without survey and there is no value for TOC newly introducing organic item. The reduction ratio of each pollutant from this study was revealed as follows; TOC, BOD, T-N and T-P were 0.34, 0.60, 0.37, and 0.42 for individual farm and 0.38, 0.61, 0.45 and 0.44 for entrustment facilities, respectively. The reduction ratio of individual farm was surveyed as TOC 0.63, BOD 0.62, T-N 0.42 and T-P 0.32 for liquid fertilizer and TOC 0.30, BOD 0.64, T-N 0.40 and T-P 0.48 for compost. Total reduction ratio was derived by multiplying the ratio for liquid fertilizer and compost by the respective load. Compared to the pollutant reduction ratio of the individual farm with entrustment facilities marking the higher in liquid fertilizer and the lower in compost. Through this study, we found the difference of pollutant reduction ratio between livestock manure recycling method and facilities. Although phosphorus known as a preservative matter, the treatment efficiency of T-P is analyzed to decrease by chemical precipitation.

Compost, Liquid fertilizer, Livestock manure fertilization, Pollutant reduction ratio, TOC (Total organic compound)

김정우 Jungwoo Kim , 김아름 Ah Reum Kim , 공동수 Dongsoo Kong

DOI:10.15681/KSWE.2017.33.6.728 Vol.33(No.6) 728-735, 2017

Many restoration projects are underway to revive disturbed streams. In order to achieve successful stream restoration, a variety of microhabitats should be created to promote biological diversity. Research on biological classification of microhabitat is essential for biological diversity. However, research on classification using only physical environmental factors has been carried out. The purpose of this study is to classify and quantify the microhabitat of stream by using macroinvertebrates systematically. In this study, eight wadeable streams and four non-wadeable streams were surveyed to identify benthic macroinvertebrates in various microhabitats. Among the physical environmental factors (current velocity, water depth, substrate), the particle size of the substrate was the most influential factor in the emergence of Habitat Orientaion Groups. Among the HOGs, clinger and burrower were highly correlated with physical environment factors and showed the opposite tendency. Distribution of clinger and burrower according to physical environmental factors showed two trendencies based on current velocity (0.3 m/s) and water depth (0.4 m). In addition, the particle size of the substrate showed three trends (≤-5.0, -5.0 < mean diameter ≤-2.0, >-2.0). Based on the abundance tendency of these two HOGs, the microhabitats were classified into nine types from eupotamic microhabitat to lentic microhabitat. Classification of microhabitat using HOGs can be employ for creating microhabitat to promote biological diversity in future stream restoration plan.

Benthic Macroinvertebrates, Habitat Orientation Groups, Microhabitats, Physical Environmental Factors

이철규 Cheal-gyu Lee

DOI:10.15681/KSWE.2017.33.6.736 Vol.33(No.6) 736-743, 2017

In this study, 4-nonylphenol (4-NP), an endocrine disrupting chemical, was removed by ozone treatment processes under the various experimental conditions including UV irradiation, TiO₂ addition. The ozone flow rate and concentration were maintained at 1.0 L·min^-1 and 70±5 mg·L^-1. The pH, COD and TOC of the samples were obtained every 10 minutes for 60 minutes in laboratory scale batch reactor. We found that the combination of UV irradiation and TiO₂ addition for ozonation improves the removal efficiency of COD and TOC in 4-NP aqueous solution. In case of the O₃/UV/TiO₂ system, COD and TOC were greatly reduced to 85.3~94.0% and 89.2~97.2%, respectively. 4-NP degradation rate constants, k_COD and k_TOC, were calculated based on the COD and TOC values. Significantly, k_COD and k_TOC were improved in the O₃/UV/TiO₂ treatment process compared with single O₃ process, because the oxidation and the mineralization of 4-NP were increased by generating of the hydroxyl radical. The k_COD and k_TOC were obtained to be 5.81×10^-4~10.8×10^-4 sec^-1 and 11.9×10^-4~19.4×10^-4 sec^-1 in the O₃/UV/TiO₂ process. Activation energy (E_a) of ozone oxidation reaction based on k_COD and k_TOC were in order of O₃/UV/TiO₂ < O₃/UV < O₃/TiO₂ < O₃ process. It was confirmed that the addition of TiO₂ and UV irradiation to the ozone oxidation reaction significantly reduced the E_a value and the degradation of 4-NP.

Activation energy, Advanced oxidation process, Ozonation, 4-nonylphenol

전지홍 Ji-Hong Jeon , 최동혁 Donghyuk Choi , 김재권 Jae-Kwon Kim , 김태동 Taedong Kim

DOI:10.15681/KSWE.2017.33.6.744 Vol.33(No.6) 744-753, 2017

The sediment delivery ratio (SDR) has been used widely to estimate sediment loads by multiplying soil loss through RUSLE. In this study, the SDR equation was developed for the Lake Imha watershed using soil loss calculated by RUSLE and sediment loads by the calibrated HSPF. The ratio of watershed relief and channel length (R_f/L_ch), the ratio of watershed relief and watershed length (R_f/L_b), curve number (CN), area (A), and channel slope (SLP_ch) demonstrated strong correlations with SDR. SDR equations were developed by a combination of subwatershed parameters by referring to the correlation analysis. The area based power functional SDR developed in this study showed significant errors at the point right after entering major tributaries, because SDR was unrealistically reduced when the watershed area increased significantly. The SLP_ch-based power functional SDR also showed extraordinary values when the channel slope was gradual. The SDR equation that showed the highest value of the coefficient of determination also presented unrealistic changes in the sediment loads within a relatively short river distance. The SDR equation SDR=0.0003A^0.198R_f/L_w^1.167 was recommended for application to the Lake Imha watershed. Using this equation, sediment loads at the outlet of the Lake Imha watershed were calculated, and the HSPF parameters related to sediment in the uncalibrated subwatersheds were determined by referring to the sediment loads calculated with the SDR equation.

Calibration, HSPF, Lake Imha, Suspended sediment loads

김민희 Minhee Kim , 현승훈 Seunghun Hyun , 이원석 Won-seok Lee

DOI:10.15681/KSWE.2017.33.6.754 Vol.33(No.6) 754-768, 2017

Polybrominated diphenyl ethers (PBDEs) are a group of industrial aromatic organobromine chemicals that have been used since the 1970s as flame retardants in a wide range of consumer products and articles, such as plastics, computers, textiles and upholstery. Commercial PBDEs were added to Annex A of the Stockholm Convention as persistent organic pollutants in May 2009. PBDEs are still frequenlty found in sludge and effluent from wastewater treatment plants, even though commercial PBDEs were prohibited or voluntarily phased out several years ago. Conventional wastewater treatment processes are not designed to effectively remove PBDEs. This indicates that there is an urgent need for new developments and improvements in currently available treatment techniques. Several studies have suggested the potential removal and degradation technologies for PBDEs in wastewater. In this study, the concentrations and compositional profiles of PBDE congeners in sludge and effluent are investigated by analyzing literature data in relation to their usage patterns in commercial products in North America and South Korea. The strengths and weaknesses of cureent PBDEs removal techniques (i.e., biodegradation, zero-valent iron, photolysis, sorption, etc.) are critically discussed. In addition, future research direction regarding on the treatment and removal of PBDEs from wastewater is also suggested based on the literature review.

Persistent organic pollutants, Polybrominated diphenyl ethers, Treatment Technologies, Wastewater treatment plant

임도영 Do Young Lim , 정유진 Eu Gene Chung , 김용석 Yongseok Kim , 김덕우 Deok-woo Kim , 유홍덕 Hong-duck Ryu

DOI:10.15681/KSWE.2017.33.6.769 Vol.33(No.6) 769-779, 2017

Nutrient (i.e., nitrogen and phosphorus) budgets are required under a 'Livestock Excreta Survey'. Nutrient budget is one of the agri-environmental indicators that calculates the difference between inputs and outputs of amount of nutrients within a certain boundary and for a period (e.g., 1 year). In this study, a nutrients budget model was developed to effectively determine the surplus of nutrients within a region in Korea. C# program language was used in order to facilitate the deployment of graphical user interface (GUI) and to enhance compatibility. Also the model was developed on Windows OS which is the commonly used operating system in Korea. The model was based on the OECD/Eurostat nutrient budget method and modified to consider manure composting procedures as well. There are key features of the nutrient budget model including directly use of original data sets from various input and output sources, and collectively exchange of the address in different formats. The model can quickly show the results in various spatial and temporal resolutions with the same data, perform the sensitivity analysis with coefficients and easily compare the results using tables and graphs. Further it would be necessary to study the extension of the scope of utilization, such as the application of various nutrient budget methods, and both pre and post processings such as linking input data through online etc.

Agri-Environment indicator, Livestock Excreta Survey, Model, Nitrogen, Nutrient Budget, Phosphorus