44 results on '"JOON HA KIM"'
Search Results
2. New methodology to develop high-resolution rainfall data using weather radar for watershed-scale water quality model
- Author
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Dong Jin Jeon, Bumjo Kim, Yakov Pachepsky, and Joon Ha Kim
- Subjects
Meteorology ,law ,Environmental science ,High resolution ,Weather radar ,Water quality ,law.invention ,Watershed scale - Published
- 2019
3. Modeling seasonal variability of fecal coliform in natural surface waters using the modified SWAT
- Author
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Minjeong Kim, JongCheol Pyo, Mi Hyun Park, Yakov Pachepsky, Jung Woo Kim, Kyung Hwa Cho, Young-Mo Kim, and Joon Ha Kim
- Subjects
Hydrology ,Soil and Water Assessment Tool ,Hydrological modelling ,0208 environmental biotechnology ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,020801 environmental engineering ,Coliform bacteria ,Water resources ,Fecal coliform ,fluids and secretions ,Hydrology (agriculture) ,Environmental science ,Water quality ,Surface water ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Fecal coliforms are indicators of pathogens and thereby, understanding of their fate and transport in surface waters is important to protect drinking water sources and public health. We compiled fecal coliform observations from four different sites in the USA and Korea and found a seasonal variability with a significant connection to temperature levels. In all observations, fecal coliform concentrations were relatively higher in summer and lower during the winter season. This could be explained by the seasonal dominance of growth or die-off of bacteria in soil and in-stream. Existing hydrologic models, however, have limitations in simulating the seasonal variability of fecal coliform. Soil and in-stream bacterial modules of the Soil and Water Assessment Tool (SWAT) model are oversimplified in that they exclude simulations of alternating bacterial growth. This study develops a new bacteria subroutine for the SWAT in an attempt to improve its prediction accuracy. We introduced critical temperatures as a parameter to simulate the onset of bacterial growth/die-off and to reproduce the seasonal variability of bacteria. The module developed in this study will improve modeling for environmental management schemes.
- Published
- 2016
4. Developing alternative regression models for describing water quality using a self-organizing map
- Author
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Seung Won Lee, Joon Ha Kim, and Seo Jin Ki
- Subjects
Self-organizing map ,0208 environmental biotechnology ,Ocean Engineering ,Feature selection ,Regression analysis ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,Pollution ,020801 environmental engineering ,Set (abstract data type) ,Statistics ,Water quality ,Scale (map) ,Raw data ,0105 earth and related environmental sciences ,Water Science and Technology ,Rank correlation ,Mathematics - Abstract
Statistical models play an important role in elucidating the dynamic behaviors of surface water quality, given limited data on a large scale. In this study, we examine alternative approaches to develop regression models that predict fecal coliform (FC) concentrations in a river using different methods for selecting important variables provided by a self-organizing map (SOM). The raw data used as input to the SOM included 11 water quality, 6 meteorological, and 7 land use parameters that were monitored along the Yeongsan River in Korea on various time scales (from daily to half a decade) during 1996–2008. In both test and validation data sets, (multiple) regressions using backward elimination were compared against regression models via forced entry, which included a set of ranked variables simultaneously based on four indices in the SOM (i.e. structuring index, relative importance, cluster description, and Spearman’s rank correlation). Results showed that the SOM effectively illustrated the complex...
- Published
- 2015
5. Stressor–response modeling using the 2D water quality model and regression trees to predict chlorophyll-a in a reservoir system
- Author
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Dong Jin Jeon, Yongeun Park, Yakov Pachepsky, Kyung Hwa Cho, and Joon Ha Kim
- Subjects
Correlation ,Variable (computer science) ,Stressor ,Statistics ,medicine ,Decision tree ,Environmental science ,Water quality ,Seasonality ,medicine.disease ,Algal bloom ,Regression ,Water Science and Technology - Abstract
Summary To control algal blooms, the stressor–response relationships between water quality metrics, environmental variables, and algal growth need to be better understood and modeled. Machine-learning methods have been suggested as means to express the stressor–response relationships that are found when applying mechanistic water quality models. The objective of this work was to evaluate the efficiency of regression trees in the development of a stressor–response model for chlorophyll-a (Chl-a) concentrations, using the results from site-specific mechanistic water quality modeling. The 2-dimensional hydrodynamic and water quality model (CE-QUAL-W2) model was applied to simulate water quality using four-year observational data and additional scenarios of air temperature increases for the Yeongsan Reservoir in South Korea. Regression tree modeling was applied to the results of these simulations. Given the well-expressed seasonality in the simulated Chl-a dynamics, separate regression trees were developed for months from May to September. The regression trees provided a reasonably accurate representation of the stressor–response dependence generated by the CE-QUAL-W2 model. Different stressors were then selected as split variables for different months, and, in most cases, splits by the same stressor variable yielded the same correlation sign between the variable and the Chl-a concentration. Compared to physical variables, nutrient content appeared to better predict Chl-a responses. The highest Chl-a temperature sensitivities were found for May and June. Regression tree splits based on ammonium concentration resulted in a consistent trend of greater sensitivity in the groups of samples with higher ammonium concentrations. Regression tree models provided a transparent visual representation of the stressor–response relationships for Chl-a and its sensitivity. Overall, the representation of relationships using classification and regression tools can be considered a useful approach to assess the state of aquatic ecosystems and effectively determine significant stressor variables.
- Published
- 2015
6. Development of enhanced groundwater arsenic prediction model using machine learning approaches in Southeast Asian countries
- Author
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Young Mo Kim, Joon Ha Kim, Mayzonee Ligaray, Yongeun Park, Kyung Hwa Cho, and Suthipong Sthiannopkao
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Groundwater arsenic ,Artificial neural network ,business.industry ,0208 environmental biotechnology ,Ocean Engineering ,02 engineering and technology ,010501 environmental sciences ,Contamination ,Southeast asian ,Machine learning ,computer.software_genre ,01 natural sciences ,Pollution ,020801 environmental engineering ,Arsenic contamination of groundwater ,Support vector machine ,Environmental science ,Water quality ,Artificial intelligence ,business ,computer ,Groundwater ,0105 earth and related environmental sciences ,Water Science and Technology - Abstract
Groundwater contamination with arsenic (As) is one of the major issues in the world, especially for Southeast Asian (SEA) countries where groundwater is the major drinking water source, especially in rural areas. Unfortunately, quantification of groundwater As contamination is another burden for those countries because it requires sophisticated equipment, expensive analysis, and well-trained technicians. Here, we collected approximately 350 groundwater samples from three different SEA countries, including Cambodia, Lao PDR, and Thailand, in an attempt to quantify total As concentrations and conventional water quality variables. After that, two machine learning models (i.e. artificial neural network (ANN) and support vector machine (SVM)) were applied to predict groundwater As contamination using conventional water quality parameters. Prior to modeling approaches, the pattern search algorithm in MATLAB software was used to optimize the ANN and SVM model parameters, attempting to find the best param...
- Published
- 2015
7. Prediction of effluent concentration in a wastewater treatment plant using machine learning models
- Author
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Jiyeon Lim, Jeongwon Jo, Kwanho Jeong, Young Mo Kim, Joon Ha Kim, Kyung Hwa Cho, Jong-Pyo Park, and Hong Guo
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Engineering ,Support Vector Machine ,Environmental Engineering ,Coefficient of determination ,Nitrogen ,Wastewater ,Machine learning ,computer.software_genre ,Sensitivity and Specificity ,Water Purification ,Water Quality ,Republic of Korea ,Environmental Chemistry ,Effluent ,General Environmental Science ,business.industry ,Environmental engineering ,General Medicine ,Prognosis ,Support vector machine ,Waste treatment ,Food waste ,Sewage treatment ,Neural Networks, Computer ,Artificial intelligence ,Stage (hydrology) ,Water quality ,business ,computer - Abstract
Of growing amount of food waste, the integrated food waste and waste water treatment was regarded as one of the efficient modeling method. However, the load of food waste to the conventional waste treatment process might lead to the high concentration of total nitrogen (T-N) impact on the effluent water quality. The objective of this study is to establish two machine learning models-artificial neural networks (ANNs) and support vector machines (SVMs), in order to predict 1-day interval T-N concentration of effluent from a wastewater treatment plant in Ulsan, Korea. Daily water quality data and meteorological data were used and the performance of both models was evaluated in terms of the coefficient of determination (R2), Nash-Sutcliff efficiency (NSE), relative efficiency criteria (drel). Additionally, Latin-Hypercube one-factor-at-a-time (LH-OAT) and a pattern search algorithm were applied to sensitivity analysis and model parameter optimization, respectively. Results showed that both models could be effectively applied to the 1-day interval prediction of T-N concentration of effluent. SVM model showed a higher prediction accuracy in the training stage and similar result in the validation stage. However, the sensitivity analysis demonstrated that the ANN model was a superior model for 1-day interval T-N concentration prediction in terms of the cause-and-effect relationship between T-N concentration and modeling input values to integrated food waste and waste water treatment. This study suggested the efficient and robust nonlinear time-series modeling method for an early prediction of the water quality of integrated food waste and waste water treatment process.
- Published
- 2015
8. Development of early-warning protocol for predicting chlorophyll-a concentration using machine learning models in freshwater and estuarine reservoirs, Korea
- Author
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Kyung Hwa Cho, Yongeun Park, Sung Min Cha, Joon Ha Kim, and Jihwan Park
- Subjects
Chlorophyll ,Engineering ,Environmental Engineering ,Fresh Water ,Interval (mathematics) ,Algal bloom ,Artificial Intelligence ,Republic of Korea ,Water Pollution, Chemical ,Environmental Chemistry ,Sensitivity (control systems) ,Waste Management and Disposal ,Hydrology ,Warning system ,Artificial neural network ,business.industry ,Chlorophyll A ,Pollution ,Support vector machine ,Models, Chemical ,Neural Networks, Computer ,Water quality ,Estuaries ,business ,Eutrophication ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
Chlorophyll-a (Chl-a) is a direct indicator used to evaluate the ecological state of a waterbody, such as algal blooms that degrade the water quality in lakes, reservoirs and estuaries. In this study, artificial neural network (ANN) and support vector machine (SVM) were used to predict Chl-a concentration for the early warning in the Juam Reservoir and Yeongsan Reservoir, which are located in an upstream region (freshwater reservoir) and downstream region (estuarine reservoir), respectively. Weekly water quality data and meteorological data for a 7-year period were used to train and validate both the ANN and SVM models. The Latin-hypercube one-factor-at-a-time (LH-OAT) method and a pattern search algorithm were applied to perform sensitivity analyses for the input variables and to optimize the parameters of the two models, respectively. Results revealed that the two models well-reproduced the temporal variation of Chl-a based on the weekly input variables. In particular, the SVM model showed better performance than the ANN model, displaying a higher prediction accuracy in the validation step. The Williams-Kloot test and sensitivity analysis demonstrated that the SVM model was superior for predicting Chl-a in terms of prediction accuracy and description of the cause-and-effect relationship between Chl-a concentration and environmental variables in both the Juam Reservoir and Yeongsan Reservoir. Furthermore, a 7-day interval was determined as an efficient early warning interval in the two reservoirs. As such, this study suggested an effective early-warning prediction method for Chl-a concentration and improved the eutrophication management scheme for reservoirs.
- Published
- 2015
9. Water quality changes according to the midstream weir construction in the Yeongsan River, Korea
- Author
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Min-Ji Kang, Sung Min Cha, Seung Won Lee, Joon Ha Kim, and Yongeun Park
- Subjects
Biochemical oxygen demand ,Suspended solids ,Aquatic ecosystem ,Weir ,Chemical oxygen demand ,Midstream ,Environmental engineering ,Environmental science ,Ocean Engineering ,STREAMS ,Water quality ,Pollution ,Water Science and Technology - Abstract
This paper describes the effects of weir construction on water quality in the Yeongsan (YS) River. In general, weirs affect aquatic environments of rivers and streams by interrupting natural water flow. To identify changes in water quality before and after weir construction, analysis of variance and autocorrelation tests were conducted on data from four monitoring stations. Seasonal variations in suspended solids (SS), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and pH were analyzed using data from six years of monitoring. No significant changes in mean BOD5 or COD followed the construction of weirs. However, mean TN and TP were changed significantly during and after construction. Moreover, SS and pH changed significantly during construction, and TN and TP concentrations were slightly improved after weir construction. However, continuous monitoring and analysis of water quality changes in each weir are required to prevent environmenta...
- Published
- 2014
10. Smart water grid: the future water management platform
- Author
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Dong Jin Jeon, Seung Won Lee, Joon Ha Kim, and Sarper Sarp
- Subjects
Engineering ,Water-energy nexus ,business.industry ,Water flow ,Environmental resource management ,Ocean Engineering ,Grid ,Pollution ,Water resources ,Information and Communications Technology ,Systems engineering ,Water quality ,business ,Intelligent control ,ComputingMethodologies_COMPUTERGRAPHICS ,Water Science and Technology ,Efficient energy use - Abstract
This study introduces a schematic methodology for smart water grids (SWGs) for use in water management platforms, which integrates information and communication technology (ICT) into a single water management scheme. SWG technology is seen as a promising solution for resolving recent critical global water problems. To ensure the security of water quantity, safety of water quality, and ICT-based water management solutions, SWG technology should integrate five prime research areas: (1) platform configuration in both water and ICT networks, (2) guarantee water resources including both natural and manufactured water, (3) intelligent control of water flow using bi-directional communication in water infrastructure, (4) better management scheme dealing with risk-minimization for assets in the water infrastructure, and (5) energy efficiency in operating and maintaining water infrastructure. Two platforms (i.e. water and ICT platforms) are introduced as examples of well-designed platforms for the managemen...
- Published
- 2014
11. Developing a flow control strategy to reduce nutrient load in a reclaimed multi-reservoir system using a 2D hydrodynamic and water quality model
- Author
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Seung Won Lee, Joo-Hyon Kang, Kyung Hwa Cho, Yongeun Park, and Joon Ha Kim
- Subjects
Pollutant ,Hydrology ,Flow control (data) ,Engineering ,Environmental Engineering ,Watershed ,business.industry ,Flow (psychology) ,Environmental engineering ,Pollution ,Open-channel flow ,Environmental Chemistry ,Seawater ,Water quality ,business ,Waste Management and Disposal ,Communication channel - Abstract
Blocking the natural bi-directional flow in an estuarine system using an artificial dyke has commonly caused serious water quality problems. In the southwestern part of South Korea, a parallel triple-reservoir system was constructed by blocking the mouth of three different rivers (Yeongsan, Okcheon, and Kumja), which were then interconnected using two open channels. This system has experienced a deterioration in water quality due to pollutants accumulated from the upper watershed, and has continually discharged pollutant loads to the outer ocean. Therefore, the objective of this study is to establish an effective dam operation plan for reducing nutrient loads released from the integrated reservoir. In this study, the CE-QUAL-W2 model, which is a 2-dimentional hydrodynamic and water quality model, was applied to predict the pollutant load released from each reservoir in response to different flow scenarios for the interconnecting channel. The model was calibrated using two novel methods: a sensitivity analysis to determine meaningful model parameters, and a pattern search to optimize the parameters. From the scenario analysis using flow control, it was determined that the total nitrogen (TN) and total phosphorus (TP) loadings could be reduced by 27.2% and 6.6%, respectively, under the optimal channel flow scenario by regulating the chlorophyll-a concentration in the reservoir. The results confirm that effective dam operation could contribute to a decrease in pollutant loads in the receiving seawater body. As such, this study suggests operational strategies for a multi-reservoir system that can be used to reduce the nutrient load being discharged from reservoirs.
- Published
- 2014
12. Characterizing water quality and quantity profiles with poor quality data in a machine learning algorithm.
- Author
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Zhonghyun Kim, Heewon Jeong, Sora Shin, Jinho Jung, Joon Ha Kim, and Seo Jin Ki
- Subjects
MULTIPLE imputation (Statistics) ,WATER quality ,DIMENSIONAL reduction algorithms ,MACHINE learning ,HOT spots (Pollution) ,DATA quality ,WATER quality monitoring - Abstract
Statistical analyses are often subject to misinterpretation due to poor data quality which is inaccurate, incomplete, or unavailable. This study describes how incomplete data diminishes the screening accuracy of water pollution hotspots using a self-organizing map (SOM), a popular algorithm in reducing the dimension of complex data in a nonlinear fashion. A full data set consisting of 12 water quality and quantity parameters monitored monthly over 3 years at the Yeongsan River in Korea was provided to SOM as a reference input. For purposes of comparison, SOM was further allowed to accept three incomplete data sets in terms of variable availability as well as data loss for single and multiple parameters and different pollution levels. We found that data loss of either single or multiple parameters exceeding 15% of the entire data set led to significant changes in spatial and temporal patterns of the original data. However, the variables intentionally unavailable in the given data set affected the screening performance of water pollution hotspots in SOM, to a less obvious extent, as long as the percentage of missing data fell below 10%. The same applied to data loss with three pollution levels, from high through moderate to low concentrations of one important variable. Therefore, we recommend the use of multiple approaches that couple dimensionality reduction algorithms with reasonable imputation methods for the data set with a high percentage (e.g. above 15%) of missing values. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
13. Improvement of reverse osmosis process stability in internally staged design under seasonal variation of feed water.
- Author
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Seung Ji Lim, Kwanho Jeong, Yong-joo Cho, Jungsu Park, Taekuk Lee, Seo Jin Ki, and Joon Ha Kim
- Subjects
WATER quality ,OCEAN temperature ,SALINE water conversion ,REVERSE osmosis ,ENERGY consumption ,WATER ,SEAWATER ,FEED additives - Abstract
In this study, we conducted a numerical simulation to evaluate stability in the seawater reverse osmosis (SWRO) process against seasonal variations of feed water. The impact of element configuration on SWRO operation was analyzed using a process model consisting of the solution--diffusion model. Seawater quality and temperature data collected from the intake of the Fujairah desalination plant (United Arab Emirates) were used to identify optimum internally staged design (ISD) configurations. Monitoring data were also used to simulate changes in SWRO performance. The process performance of the ISD configurations as compared to conventional design configurations in terms of specific energy consumption, permeate total dissolved solids concentration and recovery ratio. The results showed that SWRO processes with four ISD configurations met the performance requirements over 12 months despite the fluctuations in seawater quality and temperature. The prediction results of the ISD configurations showed stable operation during the 12 month simulation period. These configurations had a significant advantage with respect to membrane maintenance. This study's findings could be used to optimize the element configuration of the SWRO process by predicting the process performance while accounting for seasonal variations of seawater quality and temperature. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
14. Modeling the influence of future climatic variables on nutrient loading in the Yeongsan River Basin, South Korea.
- Author
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Yongeun Park, Kangmin Chon, Jae-Ki Shin, Yejee Lim, Sang-Soo Baek, and Joon Ha Kim
- Subjects
GENERAL circulation model ,STREAMFLOW ,CLIMATE change ,DIGITAL maps ,SOIL classification ,WATER quality - Abstract
Eutrophication is caused by the discharge of excess nutrients from various point and nonpoint sources. In particular, nonpoint sources of nutrients are difficult to identify because of diffuse sources and the effects of climate change. The objective of this study is to investigate the change in nutrient loading from land areas under climate change. In this study, the soil and water assessment tool (SWAT) model was applied to predict the sediment, total nitrogen (TN), and total phosphorus (TP) loads in the Yeongsan River Basin using geographical information (i.e., digital elevation map, land use, and soil type), observed data (i.e., meteorological data, streamflow, and water quality). Future climatic variables were obtained from a general circulation model, which was simulated using four representative concentration pathway (RCP) scenarios such as RCP 2.6, 4.5, 6.0, and 8.5. The results showed that flow rate, sediment load, TN load, and TP load were changed in terms of climate change under the different RCP scenarios. Impacts of climate change on a basin may be an important factor in eutrophication management in the Yeongsan River. The SWAT model provided an accurate prediction of the current nutrient pollutant loads and facilitated the reliable prediction of future nutrient pollutant loads under climate change. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
15. Characterizing particle size distribution of nonpoint source pollutants in an agricultural area
- Author
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Joon Ha Kim, Seung Won Lee, Sung Min Cha, and Yongeun Park
- Subjects
Pollutant ,Pollution ,geography ,geography.geographical_feature_category ,media_common.quotation_subject ,Stormwater ,Environmental engineering ,Drainage basin ,Ocean Engineering ,Settling ,Environmental science ,Water quality ,Surface runoff ,Nonpoint source pollution ,Water Science and Technology ,media_common - Abstract
Nonpoint source (NPS) pollution is widely recognized as a major source affecting the water quality deterioration in rivers, lakes, and marine environments. Many studies about the relations between NPS pollutants and solid matters from drainage area have been carried out in the area of stormwater management. This study collected stormwater and soil samples from a drainage area in Korea; the particle size distributions (PSDs) were then analyzed during four storm events. The results indicate that the PSDs of fine and medium silt in the stormwater are related to the soil component of the drainage area. In addition, solid matter was strongly related to NPS pollutant discharges such as total nitrogen and total phosphorus during stormwater runoff. Therefore, to design an NPS management facility, the PSD from the drainage area should be considered. It is expected that this study can be applied to the designs of settling ponds used to remove particles from stormwater runoff.
- Published
- 2013
16. Investigation of stormwater runoff strength in an agricultural area, Korea
- Author
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Lee-Hyung Kim, Sung Min Cha, Kyung Suk Min, Joon Ha Kim, Seungyoon Lee, and Seung Won Lee
- Subjects
Pollution ,geography ,geography.geographical_feature_category ,Swale ,media_common.quotation_subject ,Stormwater ,Environmental engineering ,Ocean Engineering ,Wetland ,Environmental science ,Water quality ,Low-impact development ,Surface runoff ,Water resource management ,Nonpoint source pollution ,Water Science and Technology ,media_common - Abstract
To manage and control the nonpoint source (NPS) pollution and to improve the water quality of impaired streams, rivers and lakes, practices including constructed wetlands, permeable pavement, swales and others are being attempted in the world. Before applying these techniques, an analysis of stormwater runoff characteristics should be understood due to the complexity in estimating system design factors for best management practices (BMPs). This study investigates the stormwater discharge from an agricultural area in Korea. Based on this investigation, pollutant and flow coefficient of variation (PFCoV) values were developed in an attempt to explain the stormwater runoff in the agricultural area. Four field studies categorized by rainfall type were then employed to assess the PFCoV values. The results show that the physical meaning of PFCoV values indicates the variation of NPS pollutants during a storm event. As such, this simple and meaningful result can be applied to a wide range of stormwater ...
- Published
- 2012
17. Release of Escherichia coli from the bottom sediment in a first-order creek: Experiment and reach-specific modeling
- Author
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Yakov Pachepsky, Kyung Hwa Cho, Daniel R. Shelton, Andrey Guber, Joon Ha Kim, and R. Rowland
- Subjects
Hydrology ,geography ,Water column ,geography.geographical_feature_category ,Alluvion ,Drainage basin ,Sediment ,Environmental science ,Alluvium ,Water quality ,STREAMS ,Water Science and Technology ,Volumetric flow rate - Abstract
Summary Escherichia coli release from streambed sediments may substantially affect microbial water quality. Models of E. coli release and transport commonly use a single set of parameters for the whole stream or reservoir, yet little is known about the magnitude and sources of the variability of parameters of the streambed bacteria release. The objectives of this work were: (a) to obtain and compare parameters of streambed E. coli resuspension in three stream reaches with distinctly different bottom sediment textures, and (b) to see whether the modeling of streambed E. coli resuspension with reach-specific parameters could provide substantially better accuracy than modeling with a single set of parameters. Sediment particle size distributions and the streambed E. coli concentrations were measured along a first-order creek in the USDA-ARS OPE3 experimental watershed in Maryland. Afterwards, 80 m3 of water were released into the creek at a rate of 60 L per second in four equal allotments separated by 1–3 min intervals. Flow rates and E. coli concentrations were monitored with automated samplers at the ends of the three reaches with a total length of 630 m. A high concentration of streambed E. coli (“hotspot”) resuspended within the first reach caused a pulse of high E. coli concentrations that propagated along the creek without substantial attenuation; inputs of sediment-borne E. coli from the next two reaches were relatively small. The E. coli transport model included one-dimensional Saint–Venant and advective–dispersive equations. The calibrated roughness coefficient values were comparable for the three reaches, whereas the critical stress and the entrainment rate differed among reaches by a half order and an order of magnitude, respectively. Overall, better accuracy was observed when the model contained reach-specific parameters. Additional research is needed to understand which and how sediment properties affect parameters of streambed E. coli release into the water column.
- Published
- 2010
18. Linking land-use type and stream water quality using spatial data of fecal indicator bacteria and heavy metals in the Yeongsan river basin
- Author
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Joo-Hyon Kang, Seo Jin Ki, Sung Min Cha, Kyung Hwa Cho, Joon Ha Kim, and Seung Won Lee
- Subjects
China ,Environmental Engineering ,Watershed ,Drainage basin ,Indicator bacteria ,Fresh Water ,Land cover ,Feces ,Rivers ,Metals, Heavy ,Escherichia coli ,Water Movements ,Humans ,Water Pollutants ,Water pollution ,Waste Management and Disposal ,Water Science and Technology ,Civil and Structural Engineering ,Hydrology ,geography ,geography.geographical_feature_category ,Bacteria ,Ecological Modeling ,Water Pollution ,Models, Theoretical ,Pollution ,Indicator species ,Environmental science ,Water quality ,Surface water ,Enterococcus - Abstract
This study reveals land-use factors that explain stream water quality during wet and dry weather conditions in a large river basin using two different linear models-multiple linear regression (MLR) models and constrained least squares (CLS) models. Six land-use types and three topographical parameters (size, slope, and permeability) of the watershed were incorporated into the models as explanatory variables. The suggested models were then demonstrated using a digitized elevation map in conjunction with the land-use and the measured concentration data for Escherichia coli (EC), Enterococci bacteria (ENT), and six heavy metal species collected monthly during 2007-2008 at 50 monitoring sites in the Yeongsan Watershed, Korea. The results showed that the MLR models can be a powerful tool for predicting the average concentrations of pollutants in stream water (the Nash-Sutcliffe (NS) model efficiency coefficients ranged from 0.67 to 0.95). On the other hand, the CLS models, with moderately good prediction performance (the NS coefficients ranged 0.28-0.85), were more suitable for quantifying contributions of respective land-uses to the stream water quality. The CLS models suggested that industrial and urban land-uses are major contributors to the stream concentrations of EC and ENT, whereas agricultural, industrial, and mining areas were significant sources of many heavy metal species. In addition, the slope, size, and permeability of the watershed were found to be important factors determining the extent of the contribution from each land-use type to the stream water quality. The models proposed in this paper can be considered useful tools for developing land cover guidelines and for prioritizing locations for implementing management practices to maintain stream water quality standard in a large river basin.
- Published
- 2010
19. Arsenic levels in human hair, Kandal Province, Cambodia: The influences of groundwater arsenic, consumption period, age and gender
- Author
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Joon Ha Kim, Kitirote Wantala, Suthipong Sthiannopkao, Choup Sokuntheara, Kyung Hwa Cho, Kyoung-Woong Kim, and Sieng Sotham
- Subjects
Hydrology ,chemistry.chemical_element ,Pollution ,Hazard quotient ,Geography ,chemistry ,Geochemistry and Petrology ,Environmental health ,Environmental Chemistry ,Water quality ,Rural area ,Water pollution ,Risk assessment ,Groundwater ,Arsenic ,Arithmetic mean - Abstract
This study focused on the analysis of As levels in human hair samples collected from six villages in the Kandal Province of Cambodia. Of interest were the influence of, and interactions among, certain factors affecting As intake into the human body: As concentrations in groundwater, period of groundwater consumption, age and gender. The results revealed As levels in human hair ranging from 0.06 to 30 μg g −1 with median and arithmetic mean values of 0.61 and 3.20 μg g −1 ( n = 68), respectively. Furthermore, a linear relationship was found between As concentrations in human hair and in the local groundwater. Arsenic (III) is the dominant species in Kandal groundwater, constituting in most cases at least 60% of the total As. Arsenic concentration ranged from 5 to 1543 μg L −1 , with the median value 348 μg L −1 and arithmetic mean 454 μg L −1 . In large rural, poor areas holding most of Kandal’s 1.1 million people, up to 2 in 1000 people are believed to be at risk of cancer through the As-enriched water they drink. A toxicity risk assessment provides a hazard quotient (HQ) equaling 5.12, also a clear indication of non-carcinogenic exposure risk. On the authors’ visit to Kampong Kong commune, Kandal Province, cases of arsenicosis were diagnosed in patients as a result of drinking As-enriched groundwater.
- Published
- 2010
20. A control methodology for the feed water temperature to optimize SWRO desalination process using genetic programming
- Author
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Sanghoun Oh, Joon Ha Kim, Moon Gu Jeon, In S. Kim, Young Geun Lee, and Seung Joon Kim
- Subjects
Temperature control ,Water flow ,Mechanical Engineering ,General Chemical Engineering ,Environmental engineering ,General Chemistry ,Total dissolved solids ,Desalination ,Membrane technology ,Environmental science ,General Materials Science ,Water treatment ,Water quality ,Reverse osmosis ,Water Science and Technology - Abstract
This paper presents a novel methodology to determine an optimized control method for feed water temperature in a seawater reverse osmosis (SWRO) desalination process using genetic programming (GP) which is an evolutionary algorithm used to fi nd functional forms through training data. Two functional models were determined by GP with operation data collected over four years from Fujairah SWRO plant. The models showed high accuracy (>99.0%) in terms of the average error rate between the observed and the predicted values. The fi rst model involved the permeate water fl ow rate with a functional temperature correction factor (TCF), water transfer coeffi cient, and net driving pressure (NDP) and the second is the salt passage ratio with a functional TCF, salt transfer coeffi cient, and total dissolved solids (TDS) in the feed. To determine the optimized control of the feed water temperature, a new control methodology with the two functional models was proposed and applied to a simulation of the feed water temperature, which showed better performance in terms of the permeate fl ow rate. Applying the optimized control of feed water temperatures to a plant under identical operational conditions, it was found that the permeate fl ow rate could be increased by approximately 900 m 3 /day under a steady condition of 600 ppm in permeate TDS.
- Published
- 2009
21. Interpretation of seasonal water quality variation in the Yeongsan Reservoir, Korea using multivariate statistical analyses
- Author
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Kyung Hwa Cho, Seung Won Lee, Yongeun Park, Sungmin Cha, Joo-Hyon Kang, Joon Ha Kim, and Seo Jin Ki
- Subjects
Hydrology ,Principal Component Analysis ,Korea ,Environmental Engineering ,Nitrogen ,business.industry ,Water supply ,Indicator bacteria ,Fresh Water ,Phosphorus ,Plankton ,Flood control ,Water resources ,Water Supply ,Aquatic plant ,Phytoplankton ,Principal component analysis ,Environmental science ,Water Pollutants ,Seasons ,Water quality ,business ,Environmental Monitoring ,Water Science and Technology - Abstract
The Yeongsan (YS) Reservoir is an estuarine reservoir which provides surrounding areas with public goods, such as water supply for agricultural and industrial areas and flood control. Beneficial uses of the YS Reservoir, however, are recently threatened by enriched non-point and point source inputs. A series of multivariate statistical approaches including principal component analysis (PCA) were applied to extract significant characteristics contained in a large suite of water quality data (18 variables monthly recorded for 5 years); thereby to provide the important phenomenal information for establishing effective water resource management plans for the YS Reservoir. The PCA results identified the most important five principal components (PCs), explaining 71% of total variance of the original data set. The five PCs were interpreted as hydro-meteorological effect, nitrogen loading, phosphorus loading, primary production of phytoplankton, and fecal indicator bacteria (FIB) loading. Furthermore, hydro-meteorological effect and nitrogen loading could be characterized by a yearly periodicity whereas FIB loading showed an increasing trend with respect to time. The study results presented here might be useful to establish preliminary strategies for abating water quality degradation in the YS Reservoir.
- Published
- 2009
22. Mass Load-Based Pollution Management of the Han River and Its Tributaries, Korea
- Author
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Sung Keun Yoo, Anna Ryu, Jongho Won, Jihee Moon, Jung-Woo Kim, Joon Ha Kim, Seo Jin Ki, and Heechul Choi
- Subjects
Biochemical oxygen demand ,Pollution ,Hydrology ,Global and Planetary Change ,geography ,Korea ,Watershed ,geography.geographical_feature_category ,Ecology ,media_common.quotation_subject ,Water Pollution ,Forest management ,Drainage basin ,Water Purification ,Watershed management ,Rivers ,Tributary ,Environmental science ,Water quality ,Water Microbiology ,Water resource management ,Water Pollutants, Chemical ,Environmental Monitoring ,media_common - Abstract
Spatio-temporal variations of biochemical oxygen demand (BOD) and total coliform (TC) in the Han River, Korea, were investigated in terms of concentration- based and mass loading-based approaches. Considering the river water quality criteria regulated by the Ministry of Environment in Korea, the tributaries linked to the main- stream of the Han River were found to be highly contaminated with respect to both BOD and TC and, in fact, most of the tributaries exceeded the maximum water quality criteria. To evaluate the pollution impact of tribu- taries on the mainstream, the monthly water quality monitoring data for six years (from 1995 to 2000) were collected from the Han River basin, and statistically ana- lyzed using Pearson's correlation coefficient. The results revealed that mass loading-based approach was superior to the concentration-based approach for effective Han River watershed management. Overall results supported that the mass loading-based approach associated with total maxi- mum daily loads (TMDL) management would be a useful and suitable protocol in watershed management for improving the water quality of the Han River and pro- tecting public health. Therefore, this study supporting TMDL management can be applicable to a wide array of contaminants and watershed settings in Korea.
- Published
- 2007
23. Solar and Tidal Modulations of Fecal Indicator Bacteria in Coastal Waters at Huntington Beach, California
- Author
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Joon Ha Kim, Seo Jin Ki, and Semsi Ensari
- Subjects
Pollution ,Geologic Sediments ,Time Factors ,Marsh ,Oceans and Seas ,media_common.quotation_subject ,Population Dynamics ,Indicator bacteria ,Surf zone ,Risk Assessment ,California ,Feces ,Water Movements ,Animals ,Humans ,Water Pollutants ,Health risk ,media_common ,Hydrology ,Global and Planetary Change ,geography ,geography.geographical_feature_category ,Ecology ,Nature Conservation ,Sunlight ,Environmental science ,Water quality ,Water Microbiology - Abstract
The coastal waters at many beaches in California and the United States are afflicted with fecal pollution, which poses a health risk for people exposed to the water through recreational activities such as swimming, surfing, and diving. Identifying sources of pollution is complicated by oceanographic transport/mixing processes and the nonconservative behavior of microorganisms exposed to sunlight and hostile marine conditions. This article investigates the variation of fecal indicator bacteria (FIB) concentrations in the surf zone and the adjacent coastal marsh by applying autocorrelation and cross-correlation analyses that illustrate solar and tidal modulations. A steady state bioreactor model was developed to explain solar inactivation in the surf zone, whereas a dynamic model was applied to explain tidally influenced disturbances in the coastal marsh. These models applied to intensive monitoring datasets on FIB and environmental variables have provided insights into the biologic and physical processes controlling coastal water quality, specifically the influence of sunlight and tides on bacterial levels.
- Published
- 2007
24. Public Mis-Notification of Coastal Water Quality: A Probabilistic Evaluation of Posting Errors at Huntington Beach, California
- Author
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Joon Ha Kim and Stanley B. Grant
- Subjects
Environment ,Risk Assessment ,California ,Feces ,Environmental protection ,Humans ,Environmental Chemistry ,Water Pollutants ,Health risk ,Probabilistic framework ,Information Services ,Shore ,geography ,Models, Statistical ,geography.geographical_feature_category ,business.industry ,Sampling schedule ,Environmental resource management ,Probabilistic logic ,Reproducibility of Results ,Sampling (statistics) ,General Chemistry ,Monitoring data ,Environmental science ,Public Health ,Water quality ,Water Microbiology ,business ,Algorithms ,Environmental Monitoring ,Forecasting - Abstract
Whenever measurements of fecal pollution in coastal bathing waters reach levels that might pose a significant health risk, warning signs are posted on public beaches in California. Analysis of historical shoreline monitoring data from Huntington Beach, southern California, reveals that protocols used to decide whether to post a sign are prone to error. Errors in public notification (referred to here as posting errors) originate from the variable character of pollutant concentrations in the ocean, the relatively infrequent sampling schedule adopted by most monitoring programs (daily to weekly), and the intrinsic error associated with binary advisories in which the public is either warned or not. In this paper, we derive a probabilistic framework for estimating posting error rates, which at Huntington Beach range from 0 to 41%, and show that relatively high sample-to-sample correlations (0.4) are required to significantly reduce binary advisory posting errors. Public mis-notification of coastal water quality can be reduced by utilizing probabilistic approaches for predicting current coastal water quality, and adopting analog, instead of binary, warning systems.
- Published
- 2004
25. Decadal and Shorter Period Variability of Surf Zone Water Quality at Huntington Beach, California
- Author
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Wellman De, McGee Cd, Foley Dm, Catherine D. Clark, Mowbray Sl, Stanley B. Grant, Joon Ha Kim, and Alexandria B. Boehm
- Subjects
Indicator bacteria ,Surf zone ,California ,Enterobacteriaceae ,Water Movements ,medicine ,Humans ,Environmental Chemistry ,Seawater ,Water Pollutants ,Longitudinal Studies ,Water pollution ,Hydrology ,Shore ,geography ,geography.geographical_feature_category ,Sewage ,Storm ,General Chemistry ,Seasonality ,medicine.disease ,Environmental science ,Seasons ,Water quality ,Water Microbiology ,Surface runoff ,Environmental Monitoring - Abstract
The concentration of fecal indicator bacteria in the surf zone at Huntington Beach, CA, varies over time scales that span at least 7 orders of magnitude, from minutes to decades. Sources of this variability include historical changes in the treatment and disposal of wastewater and dry weather runoff, El Niño events, seasonal variations in rainfall, spring-neap tidal cycles, sunlight-induced mortality of bacteria, and nearshore mixing. On average, total coliform concentrations have decreased over the past 43 years, although point sources of shoreline contamination (storm drains, river outlets, and submarine outfalls) continue to cause transiently poor water quality. These transient point sources typically persist for 5-8 yr and are modulated by the phase of the moon, reflecting the influence of tides on the sourcing and transport of pollutants in the coastal ocean. Indicator bacteria are very sensitive to sunlight therefore, the time of day when samples are collected can influence the outcome of water quality testing. These results demonstrate that coastal water quality is forced by a complex combination of local and external processes and raise questions about the efficacy of existing marine bathing water monitoring and reporting programs.
- Published
- 2002
26. The modified SWAT model for predicting fecal coliforms in the Wachusett Reservoir Watershed, USA
- Author
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Jung-Woo Kim, Joon Ha Kim, Yakov Pachepsky, Mi-Hyun Park, and Kyung Hwa Cho
- Subjects
Hydrology ,Geologic Sediments ,Environmental Engineering ,Watershed ,Soil and Water Assessment Tool ,Ecological Modeling ,Models, Theoretical ,Pollution ,Coliform bacteria ,Watershed management ,Fecal coliform ,Water resources ,Feces ,fluids and secretions ,Enterobacteriaceae ,Massachusetts ,Calibration ,Environmental science ,Water quality ,SWAT model ,Water Microbiology ,Waste Management and Disposal ,Water Science and Technology ,Civil and Structural Engineering - Abstract
This study assessed fecal coliform contamination in the Wachusett Reservoir Watershed in Massachusetts, USA using Soil and Water Assessment Tool (SWAT) because bacteria are one of the major water quality parameters of concern. The bacteria subroutine in SWAT, considering in-stream bacteria die-off only, was modified in this study to include solar radiation-associated die-off and the contribution of wildlife. The result of sensitivity analysis demonstrates that solar radiation is one of the most significant fate factors of fecal coliform. A water temperature-associated function to represent the contribution of beaver activity in the watershed to fecal contamination improved prediction accuracy. The modified SWAT model provides an improved estimate of bacteria from the watershed. Our approach will be useful for simulating bacterial concentrations to provide predictive and reliable information of fecal contamination thus facilitating the implementation of effective watershed management.
- Published
- 2011
27. Prediction of contamination potential of groundwater arsenic in Cambodia, Laos, and Thailand using artificial neural network
- Author
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Suthipong Sthiannopkao, Kyoung-Woong Kim, Kyung Hwa Cho, Yakov Pachepsky, and Joon Ha Kim
- Subjects
Environmental Engineering ,Time Factors ,Southeast asian ,Arsenic ,Rivers ,Linear regression ,Waste Management and Disposal ,Groundwater ,Water Science and Technology ,Civil and Structural Engineering ,Principal Component Analysis ,Geography ,Ecological Modeling ,Water Pollution ,Environmental engineering ,Electric Conductivity ,Collinearity ,Contamination ,Hydrogen-Ion Concentration ,Thailand ,Pollution ,Nonlinear Dynamics ,Laos ,Principal component analysis ,Linear Models ,Environmental science ,Principal component regression ,Water quality ,Neural Networks, Computer ,Water resource management ,Cambodia ,Oxidation-Reduction ,Water Pollutants, Chemical - Abstract
The arsenic (As) contamination of groundwater has increasingly been recognized as a major global issue of concern. As groundwater resources are one of most important freshwater sources for water supplies in Southeast Asian countries, it is important to investigate the spatial distribution of As contamination and evaluate the health risk of As for these countries. The detection of As contamination in groundwater resources, however, can create a substantial labor and cost burden for Southeast Asian countries. Therefore, modeling approaches for As concentration using conventional on-site measurement data can be an alternative to quantify the As contamination. The objective of this study is to evaluate the predictive performance of four different models; specifically, multiple linear regression (MLR), principal component regression (PCR), artificial neural network (ANN), and the combination of principal components and an artificial neural network (PC-ANN) in the prediction of As concentration, and to provide assessment tools for Southeast Asian countries including Cambodia, Laos, and Thailand. The modeling results show that the prediction accuracy of PC-ANN (Nash–Sutcliffe model efficiency coefficients: 0.98 (traning step) and 0.71 (validation step)) is superior among the four different models. This finding can be explained by the fact that the PC-ANN not only solves the problem of collinearity of input variables, but also reflects the presence of high variability in observed As concentrations. We expect that the model developed in this work can be used to predict As concentrations using conventional water quality data obtained from on-site measurements, and can further provide reliable and predictive information for public health management policies.
- Published
- 2011
28. Advancing assessment and design of stormwater monitoring programs using a self-organizing map: characterization of trace metal concentration profiles in stormwater runoff
- Author
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Joon Ha Kim, Joo-Hyon Kang, Yun Seok Lee, Seo Jin Ki, Kyung Hwa Cho, Kwang-Guk An, and Seung Won Lee
- Subjects
Environmental Engineering ,Rain ,Stormwater ,Water supply ,Rivers ,Water Supply ,Republic of Korea ,Water Movements ,Water Pollutants ,Waste Management and Disposal ,Water Science and Technology ,Civil and Structural Engineering ,Pollutant ,Hydrology ,Discharge ,business.industry ,Ecological Modeling ,Environmental engineering ,Pollution ,Current (stream) ,Metals ,Environmental science ,Water quality ,Neural Networks, Computer ,business ,Surface runoff ,Surface water ,Algorithms ,Environmental Monitoring - Abstract
Stormwater runoff poses a great challenge to the scientific assessment of the effects of diffuse pollution sources on receiving waters. In this study, a self-organizing map (SOM), a research tool for analyzing specific patterns in a large array of data, was applied to the monitoring data obtained from a stormwater monitoring survey to acquire new insights into stream water quality profiles under different rainfall conditions. The components of the input data vectors used by the SOM included concentrations of 10 metal elements, river discharge, and rainfall amount which were collected at the inlet and endpoint of an urban segment of the Yeongsan River, Korea. From the study, it was found that the SOM displayed significant variability in trace metal concentrations for different monitoring sites and rainfall events, with a greater impact of stormwater runoff on stream water quality at the upstream site than at the downstream site, except under low rainfall conditions (≤ 4 mm). In addition, the SOM clearly determined the water quality characteristics for "non-storm" and "storm" data, where the parameters nickel and arsenic and the parameters chromium, cadmium, and lead played an important role in reflecting the spatial and temporal water quality, respectively. When the SOM was used to examine the efficacy of stormwater quality monitoring programs, between 34 and 64% of the sample size in the current data set was shown to be sufficient for estimating the stormwater pollutant loads. The observed errors were small, generally being below 10, 6, and 20% for load estimation, map resolution, and clustering accuracy, respectively. Thus, the method recommended may be used to minimize monitoring costs if both the efficiency and accuracy are further determined by examining a large existing data set.
- Published
- 2010
29. Evaluation of the relationship between two different methods for enumeration fecal indicator bacteria: colony-forming unit and most probable number
- Author
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Dukki Han, Joon Ha Kim, Kyung Hwa Cho, Seung Won Lee, Joo-Hyon Kang, Sung Min Cha, and Yongeun Park
- Subjects
Veterinary medicine ,Environmental Engineering ,Colony Count, Microbial ,Indicator bacteria ,Biology ,Microbiology ,Feces ,Rivers ,Most probable number ,Enumeration ,Escherichia coli ,Water Movements ,Environmental Chemistry ,Animals ,General Environmental Science ,Colony-forming unit ,food and beverages ,General Medicine ,Coliform bacteria ,Fecal coliform ,Linear Models ,Water quality ,Seasons ,Water Microbiology ,Enterococcus - Abstract
Most probable number (MPN) and colony-forming unit (CFU) estimates of fecal indicator bacteria (FIB) concentration are common measures of water quality in aquatic environments. Thus, FIB intensively monitored in Yeongsan Watershed in an attempt to compare two different methods and to develop a statistical model to convert from CFU to MPN estimates or vice versa. As a result, the significant difference was found in the MPN and CFU estimates. The enumerated Escherichia coli concentrations in MPN are greater than those in CFU, except for the measurement in winter. Especially in fall, E. coli concentrations in MPN are one order of magnitude greater than that in CFU. Contrarily, enterococci bacteria in MPN are lower than those in CFU. However, in general, a strongly positive relationship are found between MPN and CFU estimates. Therefore, the statistical models were developed, and showed the reasonable converting FIB concentrations from CFU estimates to MPN estimates. We expect this study will provide preliminary information towards future research on whether different analysis methods may result in different water quality standard violation frequencies for the same water sample.
- Published
- 2010
30. Effect of environmental flow management on river water quality: a case study at Yeongsan River, Korea
- Author
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Heechul Choi, Kyung Hwa Cho, Seo Jin Ki, Joon Ha Kim, and Sung Min Cha
- Subjects
Hydrology ,Biochemical oxygen demand ,Environmental Engineering ,Korea ,Water Movements ,Water ,Seasonality ,Monsoon ,Spatial distribution ,medicine.disease ,Dilution ,Rivers ,Environmental monitoring ,medicine ,Environmental science ,Water quality ,Water Science and Technology ,Environmental Monitoring - Abstract
This paper describes a management scheme to control river water quality using additional water discharges from upstream dams, which results in an increase environmental flow (EF) followed by an enhancement of water quality in a target river. To suggest a creditable management plan among a suite of ideal scenarios, the monthly averaged water quality monitoring data from 2001 to 2006 at the Yeongsan (YS) River, Korea were investigated with respect to seasonal variation and spatial distribution. From the analysis, it was found that while biochemical oxygen demand (BOD5) level in the YS River was extremely high during the dry/drought season (April, May, and June; AMJ), the level was subsequently decreased during the monsoon season (July, August, and September; JAS) due mainly to the dilution effect of rainfall. To improve the water quality in AMJ, we here suggested a scenario of increasing EF using surplus water discharges from upstream dams, which was examined by one dimensional riverine water quality model, QUAL2E model. Simulation result showed that additional discharge from the upstream dams could lead, on average, to a 36% of water quality improvement in mainstream with respect to BOD5. Model coefficients were validated by comparing the six year monitoring data to minimize a sum of squares error, and showed a good agreement with the observed data. Overall, the methodology developed in this paper appears to be quite clear and straightforward, and thus, can be applied to a wide range of the flow managements or water quality controls in a stream with artificial structures.
- Published
- 2009
31. Evaluation of pollutants removal efficiency to achieve successful urban river restoration
- Author
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Seung Won Lee, Sung Min Cha, Yongeun Park, Joon Ha Kim, Kyung Hwa Cho, Young Sik Ham, and Seo Jin Ki
- Subjects
Pollution ,Biochemical oxygen demand ,Environmental Engineering ,Urban stream ,media_common.quotation_subject ,Wetland ,Rivers ,Escherichia coli ,Environmental Restoration and Remediation ,Water Science and Technology ,media_common ,Pollutant ,geography ,geography.geographical_feature_category ,Korea ,Environmental engineering ,Models, Theoretical ,Water resources ,Oxygen ,Wetlands ,Constructed wetland ,Environmental science ,Regression Analysis ,Water quality ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
Greater efforts to provide alternative scenarios are key to successful urban stream restoration planning. In this study, we discuss two different aspects of water quality management schemes, biodegradation and human health, which are incorporated in the restoration project of original, pristine condition of urban stream at the Gwangju (GJ) Stream, Korea. For this study, monthly monitoring of biochemical oxygen demand (BOD5) and fecal indicator bacteria (FIB) data were obtained from 2003 to 2008 and for 2008, respectively, and these were evaluated to explore pollutant magnitude and variation with respect to space and time window. Ideal scenarios to reduce target pollutants were determined based on their seasonal characteristics and correlations between the concentrations at a water intake and discharge point, where we suggested an increase of environmental flow and wetland as pollutants reduction drawing for BOD5 and FIB, respectively. The scenarios were separately examined by the Qual2E model and hypothetically (but planned) constructed wetland, respectively. The results revealed that while controlling of the water quality at the intake point guaranteed the lower pollution level of BOD5 in the GJ Stream, a wetland constructed at the discharge point may be a promising strategy to mitigate mass loads of FIB. Overall, this study suggests that a combination of the two can be plausible scenarios not only to support sustainable urban water resources management, but to enhance a quality of urban stream restoration assignment.
- Published
- 2009
32. Statistical assessment for spatio-temporal water quality in Angkor, Cambodia
- Author
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Suthipong Sthiannopkao, Yun Seok Lee, Joo-Hyon Kang, Joon Ha Kim, Young Geun Lee, and Seo Jin Ki
- Subjects
Pollution ,Chlorophyll ,Geologic Sediments ,Environmental Engineering ,Nitrogen ,media_common.quotation_subject ,Fresh Water ,Statistics, Nonparametric ,Water Supply ,Water Science and Technology ,media_common ,Pollutant ,Hydrology ,Analysis of Variance ,Chlorophyll A ,Electric Conductivity ,Temperature ,Sediment ,Phosphorus ,Hydrogen-Ion Concentration ,Carbon ,Water resources ,Oxygen ,Environmental science ,Spatial variability ,Water quality ,Cambodia ,Surface water ,Groundwater ,Environmental Monitoring - Abstract
Comprehensive water quality monitoring was conducted to assess the water quality conditions and to determine the impact of urban infrastructure on ambient water quality in Angkor, Cambodia. During this study, surface water, groundwater, and sediment samples were collected for two distinctive seasons in 2006–2007 at 58 monitoring sites along and near the Siem Reap River, in Tole Sap Lake (TSL), and West Baray, the primary water resources in this region. To assess the seasonal and spatial variability of 27 water quality parameters, multivariate analysis of variance, hierarchical cluster analysis, and the Kruskal-Wallis test were conducted using the obtained data. Differences and relationships between the surface water and groundwater were also investigated using t-test and correlation analysis, respectively. The results of these tests showed that the bacterial indicators need special attention as the urban infrastructure of the downtown area caused increased levels of these bacterial indicators in both surface water and groundwater. However, for most parameters, though surface water showed strong seasonal variations, groundwater presented relatively stable conditions between seasons (p>0.05) with site-specific geochemical conditions. Sediment quality illustrated that pollution levels of 10 trace metals were the highest in TSL because of its unique characteristic (river with backward flow), but did not reflect any potential enrichment from urban development. Overall, the results reveal that while the urban infrastructure in this region has not significantly affected most of the water quality parameters, bacteria and coliphages are still a main concern due to their contributions in widespread waterborne diseases. Thus, careful mitigation plans for reducing each pollutant source are needed in the Angkor area.
- Published
- 2009
33. Decadal and seasonal scale changes of an artificial lake environment after blocking tidal flows in the Yeongsan Estuary region, Korea
- Author
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Young Geun, Lee, Kwang-Guk, An, Phuc Thi, Ha, Keun-Young, Lee, Joo-Hyon, Kang, Sung Min, Cha, Kyung Hwa, Cho, Yun Seok, Lee, In Seop, Chang, Kyoung-Woong, Kim, Joon Ha, Kim, and Joon Ha, Kimj
- Subjects
Hydrology ,geography ,Geologic Sediments ,Environmental Engineering ,geography.geographical_feature_category ,Brackish water ,Aquatic ecosystem ,Lake ecosystem ,Fishes ,Sediment ,Estuary ,Fresh Water ,Biodiversity ,Pollution ,Republic of Korea ,Environmental Chemistry ,Environmental science ,Animals ,Water quality ,Seasons ,Eutrophication ,Waste Management and Disposal ,Surface water ,Ecosystem - Abstract
Artificial lakes, initially built in estuaries for positive purposes such as flood prevention and providing irrigation water, have been found to have negative impacts including blocking tidal cycles, disappearance of brackish water zones, sediment increase, water pollution, change of microbial diversity inhabiting patterns, and a decline in fish diversity. In this study, multidisciplinary field studies including physical, chemical, and biological analyses were performed to demonstrate decadal and seasonal scale changes in the ecological environment in Yeongsan Reservoir (YSR), Korea, since the construction of a 4.35 km-long dam in 1981. The results of the study show that the volume of sediment accumulated in YSR was 75.2 million m(3) since the dam was constructed, resulting in a 33.6% reduction of the total water storage capacity. Also, water quality in YSR was affected by complex physico-chemical and hydrological phenomena, including saline and thermal stratifications, and pollutant loadings leading to eutrophication. Subsequent sediment bacteria analyses showed microbial diversity according to different depths in sediment, indicating the environmental change of sediment ecology. Moreover, the fish diversity in this study (2006-2007) was found to be considerably reduced compared to a similar study in 1989 (42% reduction), and the ecological health was deemed to be in a "poor" condition based on the 10-metric Lentic Ecosystem Health Assessment (LEHA) model. Accordingly, these results indicate that aquatic ecosystems are detrimentally affected by estuarine dams that block tidal flows, and when applied to short/long-term management strategies for artificial lakes in estuaries, suggest that similar construction projects have to be suitably controlled.
- Published
- 2009
34. Characteristics of wet and dry weather heavy metal discharges in the Yeongsan Watershed, Korea
- Author
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Kyung Hwa Cho, Joo-Hyon Kang, Sung Min Cha, Joon Ha Kim, Young Geun Lee, Seo Jin Ki, and Yun Seok Lee
- Subjects
Pollutant ,Hydrology ,Environmental Engineering ,Korea ,Rain ,Environmental engineering ,Pollution ,Monitoring program ,Water Supply ,Metals, Heavy ,Water Movements ,Environmental Chemistry ,Environmental science ,Water quality ,Seasons ,Water pollution ,Surface runoff ,Waste Management and Disposal ,Surface water ,Weather ,Nonpoint source pollution ,Water Pollutants, Chemical ,Urban runoff ,Environmental Monitoring - Abstract
A comprehensive water quality monitoring program was conducted in the Yeongsan (YS) River, Korea from 2005 to present to investigate wet and dry weather pollutant discharge in an attempt to establish point and non-point pollution management strategies. As part of this monitoring program, 11 heavy metal species were measured during dry and wet weather conditions in the YS River, where Gwangju City (GJ), a subcatchment of the YS River, was further monitored to clarify the responsibility of different metal species discharged into the mainstream. Monthly grab water samples showed that greater amounts of metals along the YS River were discharged during the wet summer months due largely to storm runoff. In addition, further monitoring results revealed that GJ, a highly urbanized area, was a significant contributor of the heavy metals being discharged into the YS River during both wet and dry weather. The most abundant metal species discharged from GJ were manganese, aluminum and iron with different contributions of wet and dry weather flows to the total discharge load. Wet weather flow was a significant contributor to the annual dissolved metal loads, accounting for 44-93% of the annual load depending on the metal species, with the exception of chromium and cadmium (9% and 27%, respectively). Mostly, metal loads during wet weather were shown to be proportional to the rainfall depth and antecedent dry period. A substantial fraction of metals were also associated with solids, suggesting that sedimentation might be an appropriate management practice for reducing the metal load generated in GJ. Overall, although dissolved metal concentrations in YS River were at an acceptable level for aquatic community protection, continual metal discharge throughout the year was considered to be a potential problem in the long-term due to gradual water quality degradation as well as continuous metal accumulation in the system.
- Published
- 2008
35. Spatial and temporal pollutant budget analyses toward the total maximum daily loads management for the Yeongsan watershed in Korea
- Author
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Young-Joo Lee, Joon Ha Kim, Yuseung Lee, Soo-Kyoung Kim, and Seo Jin Ki
- Subjects
Biochemical oxygen demand ,Pollutant ,Hydrology ,Pollution ,Environmental Engineering ,Watershed ,Korea ,media_common.quotation_subject ,Water Pollution ,Sediment ,Watershed management ,Water Supply ,River management ,Environmental science ,Water Pollutants ,Water quality ,Water Science and Technology ,media_common ,Environmental Monitoring - Abstract
This paper delivers two issues: water quality in the Yeongsan (YS) watershed which is one of the major watersheds in Korea and new watershed management plans with respect to the total maximum daily loads (TMDL) management. Field studies were conducted to estimate the pollutant loads according to the spatial and temporal distribution based on the biochemical oxygen demand (BOD) concentration and the volumetric flow rate (VFR) data from YS watershed. The results of both spatial and temporal analyses show the main pollutant source was originated from the city of Gwangju and the pollutant load from the city to YS watershed was the most out of five cities during this study period. Concerning YS reservoir located downstream of YS watershed, it also shows the worst water quality in the entire watershed during the study period. These results collectively demonstrate that the city of Gwangju is a main region which generates numerous point and non-point pollutant sources and eventually the pollutants are accumulated in YS reservoir. Based on the results, we suggest two different management plans for YS watershed. One is the flow-control approach that is to increase the amount of dam discharge in order to guarantee the river management flow for the midstream region. The other is the mass-control approach that is to dredge the contaminated sediments in YS reservoir for removing pollutants chronically accumulated in the sediment. Simulations for the former and the latter provide the pollution mitigation rate in the watershed up to 6 and 8% for BOD5, respectively. The methodology proposed here for TMDL management can be applied to a wide range of watersheds in Korea.
- Published
- 2007
36. Assessing the efficiency of aggregate low impact development (LID) at a small urbanized sub-catchment under different storm scenarios.
- Author
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Dong Jin Jeon, Seo Jin Ki, Sang-Soo Baek, YoonKyung Cha, Kyung Hwa Cho, Kwang-Sik Yoon, Hyun Suk Shin, and Joon Ha Kim
- Subjects
STORMS ,RUNOFF ,WATER management ,WATER quality ,FIELD research ,SOIL infiltration ,RAINSTORMS - Abstract
While the size of single low impact development (LID) unit determines the performance in attenuating water quantity and quality from storm runoff, the performance of multiple LID units is sensitive to both their size and arrangement order. This study describes a methodology to obtain the best performance for multiple LID units under varying by time-to-peak of storm with the same intensity and duration using storm water management model (SWMM), a popular model for rainfall-runoff and water quality simulation. The hypothetical temporal distributions were designated by Huff curves, which provided characterizing storm mass curves, along with the relationship of intensity-duration-frequency to determine storm intensity for 1-h in 2-year return period. Three types of LID units (rain barrel, infiltration trench, and vegetative swale) were selected to develop aggregate LID scenarios using the SWMM. The results indicated that, when compared with other field experiments, the SWMM successfully estimated change in flow discharge and suspended solid (SS) loss reflecting different storm patterns at the final outlet of and urbanized sub-catchment as well as the effects of LID practices. The performances of aggregate LID scenarios including lag time of peak runoff, peak runoff reduction, volume reduction, and SS loss reduction were sensitive to arrangement order and time-of-storm peak-to-storm duration. Scenario 5, which had the order of vegetative swale, rain barrel, and infiltration trench, showed the most effective serial arrangement, as it exhibited the more consistent results across the storm patters. This study thus provides insights into the effective design of aggregate LID scenarios considering different storm characteristics. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
37. Generation of enterococci bacteria in a coastal saltwater marsh and its impact on surf zone water quality
- Author
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G V Leipzig, Angela C. Brown, Brett F. Sanders, Charles D. McGee, Jeremy A. Redman, N A Gardiner, B H Jones, A K Chu, R D Mrse, Stanley B. Grant, M Gouldin, J Svejkovsky, Alexandria B. Boehm, and Joon Ha Kim
- Subjects
Conservation of Natural Resources ,Marsh ,Population Dynamics ,Wetland ,Surf zone ,Feces ,Environmental Chemistry ,Humans ,Water pollution ,Life Below Water ,Ecosystem ,Urban runoff ,Hydrology ,geography ,geography.geographical_feature_category ,fungi ,Water Pollution ,General Chemistry ,Salt marsh ,Environmental science ,Water quality ,Surface runoff ,Water Microbiology ,Environmental Sciences ,geographic locations ,Enterococcus ,Environmental Monitoring - Abstract
Elevated levels of enterococci bacteria, an indicator of fecal pollution, are routinely detected in the surf zone at Huntington State and City Beaches in southern California. A multidisciplinary study was carried out to identify sources of enterococci bacteria landward of the coastline. We find that enterococci bacteria are present at high concentrations in urban runoff, bird feces, marsh sediments, and on marine vegetation. Surprisingly, urban runoff appears to have relatively little impact on surf zone water quality because of the long time required for this water to travel from its source to the ocean. On the other hand, enterococci bacteria generated in a tidal saltwater marsh located near the beach significantly impact surf zone water quality. This study identifies a potential tradeoff between restoring coastal wetlands and protecting beach water quality and calls into question the use of ocean bathing water standards based on enterococci at locations near coastal wetlands.
- Published
- 2001
38. Factors dominating stratification cycle and seasonal water quality variation in a Korean estuarine reservoir
- Author
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Sung Min Cha, Seung Won Lee, Seo Jin Ki, Joo-Hyon Kang, Yongeun Park, Kyung Hwa Cho, Young Geun Lee, Joon Ha Kim, and Yun Seok Lee
- Subjects
Hydrology ,Principal Component Analysis ,geography ,geography.geographical_feature_category ,Public Health, Environmental and Occupational Health ,Drainage basin ,Stratification (water) ,Fresh Water ,Estuary ,General Medicine ,Eutrophication ,Management, Monitoring, Policy and Law ,Seasonality ,medicine.disease ,Monitoring program ,Water Supply ,Republic of Korea ,medicine ,Environmental science ,East Asian Monsoon ,Water Pollutants ,Seasons ,Water quality ,Environmental Monitoring - Abstract
A comprehensive monitoring program was conducted during 2005-2007 to investigate seasonal variations of hydrologic stability and water quality in the Yeongsan Reservoir (YSR), located at the downstream end of the Yeongsan River, Korea. A principal component analysis (PCA) was performed to identify factors dominating the seasonal water quality variation from a large suite of measured data--11 physico-chemical parameters from 48 sampling sites. The results showed that three principal components explained approximately 62% of spatio-seasonal water quality variation, which are related to stratifications, pollutant loadings and resultant eutrophication, and the advective mixing process during the episodic rainfall-runoff events. A comparison was then made between YSR and an upstream freshwater reservoir (Damyang Reservoir, DYR) in the same river basin during an autumn season. It was found that the saline stratification and pollutant input from the upstream contributed to greater concentrations of nutrients and organic matter in YSR compared to DYR. In YSR, saline stratification in combination with thermal stratification was a dominant cause of the longer period (for two consecutive seasons) of hypoxic conditions at the reservoir bottom. The results presented here will help better understand the season- and geography-dependent characteristics of reservoir water quality in Asian Monsoon climate regions such as Korea.
- Published
- 2010
39. Factors affecting metal exchange between sediment and water in an estuarine reservoir: A spatial and seasonal observation
- Author
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In-Ho Yoon, Kyung Hwa Cho, Kyoung-Woong Kim, Keun-Young Lee, Young Geun Lee, Seo Jin Ki, Sung Min Cha, Joon Ha Kim, Joo-Hyon Kang, and Yun Seok Lee
- Subjects
Geologic Sediments ,Iron ,Water supply ,Fresh Water ,Management, Monitoring, Policy and Law ,Bottom water ,Water Supply ,Anaerobiosis ,Hydrology ,Manganese ,geography ,Korea ,geography.geographical_feature_category ,business.industry ,Aquatic ecosystem ,Public Health, Environmental and Occupational Health ,Sediment ,Estuary ,General Medicine ,Anoxic waters ,Oxygen ,Salinity ,Solubility ,Environmental science ,Seasons ,Water quality ,business ,Water Pollutants, Chemical ,Environmental Monitoring - Abstract
Water quality response in a reservoir has often been assessed using relatively restricted datasets that cannot provide sufficient information, thereby giving rise to a dramatic over- or underestimate of actual figures. In this paper we discuss how the levels of metallic elements between the sediment and overlying water in an estuarine reservoir can be influenced by aquatic parameters in response to spatial and seasonal conditions. To better elucidate the interfacial exchange between sediment and water, statistical analyses are employed to intensive data sets collected from the Yeongsan Reservoir (YSR), Korea, which has undergone widespread deterioration in water quality due to the continuous growth of anthropogenic sources. During three seasonal sampling campaigns, we found that oxygen deficiency at the bottom water layer promotes Fe and Ni accumulation in sediment, likely due to the formation of sulfide and oxide complexes under anoxic and suboxic environments, respectively. In addition, salinity levels as high as 11 per thousand in the bottom water layer during autumn substantially increase the release of Mn, restricting the use of YSR as a primary source of agricultural irrigation water. Although most dissolved metals are at acceptable levels for sustaining aquatic life, it is recommended that for long-term planning the elevated Fe and Mn levels in sediment should be controlled with oxygen deficiency during dry weather to ensure a sustainable water supply or, at a minimum, better coordinated operation of YSR.
- Published
- 2009
40. Water quality changes according to the midstream weir construction in the Yeongsan River, Korea.
- Author
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Sung Min Cha, Min-Ji Kang, Yongeun Park, Seung Won Lee, and Joon Ha Kim
- Subjects
WATER quality ,WEIRS ,BIOCHEMICAL oxygen demand ,WATER quality monitoring ,SUSPENDED solids ,CHEMICAL oxygen demand - Abstract
This paper describes the effects of weir construction on water quality in the Yeongsan (YS) River. In general, weirs affect aquatic environments of rivers and streams by interrupting natural water flow. To identify changes in water quality before and after weir construction, analysis of variance and autocorrelation tests were conducted on data from four monitoring stations. Seasonal variations in suspended solids (SS), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and pH were analyzed using data from six years of monitoring. No significant changes in mean BOD5 or COD followed the construction of weirs. However, mean TN and TP were changed significantly during and after construction. Moreover, SS and pH changed significantly during construction, and TN and TP concentrations were slightly improved after weir construction. However, continuous monitoring and analysis of water quality changes in each weir are required to prevent environmental disasters such as algal blooms. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
41. A new methodology for determining dispersion coefficient using ordinary and partial differential transport equations.
- Author
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Kyung Hwa Cho, Seungwon Lee, Young Sik Ham, Jin Hwan Hwang, Sung Min Cha, Yongeun Park, and Joon Ha Kim
- Subjects
METHODOLOGY ,RIVER conservation ,HYDRAULIC structures ,WATER quality ,WATER pollution ,DISPERSION (Chemistry) ,RIVERS - Abstract
The present study proposes a methodology for determining the effective dispersion coefficient based on the field measurements performed in Gwangju (GJ) Creek in South Korea which is environmentally degraded by the artificial interferences such as weirs and culverts. Many previous works determining the dispersion coefficient were limited in application due to the complexity and artificial interferences in natural stream. Therefore, the sequential combination of N-Tank-In-Series (NTIS) model and Advection-Dispersion-Reaction (ADR) model was proposed for evaluating dispersion process in complex stream channel in this study. The series of water quality data were intensively monitored in the field to determine the effective dispersion coefficient of E. coli in rainy day. As a result, the suggested methodology reasonably estimates the dispersion coefficient for GJ Creek with 1.25m
2 /s. Also, the sequential combined method provided Number of tank-Velocity-Dispersion coefficient (NVD) curves for convenient evaluation of dispersion coefficient of other rivers or streams. Comparing the previous studies, the present methodology is quite general and simple for determining the effective dispersion coefficients which are applicable for other rivers and streams. [ABSTRACT FROM AUTHOR]- Published
- 2009
- Full Text
- View/download PDF
42. An analytical model for non-conservative pollutants mixing in the surf zone.
- Author
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Seo Jin Ki, Jin Hwan Hwang, Joo-Hyon Kang, and Joon Ha Kim
- Subjects
WATER pollution ,HYDRODYNAMICS ,BEACHES ,POLLUTANTS ,WATER quality management ,WATER quality - Abstract
Accurate simulation of the surf zone is a prerequisite to improve beach management as well as to understand the fundamentals of fate and transport of contaminants. In the present study, a diagnostic model modified from a classic solute model is provided to illuminate non-conservative pollutants behavior in the surf zone. To readily understand controlling processes in the surf zone, a new dimensionless quantity is employed with index of kappa number (K, a ratio of inactivation rate to transport rate of microbial pollutant in the surf zone), which was then evaluated under different environmental frames during a week simulation period. The sensitivity analysis showed that hydrodynamics and concentration gradients in the surf zone mostly depend on n (number of rip currents), indicating that n should be carefully adjusted in the model. The simulation results reveal, furthermore, that large deviation typically occurs in the daytime, signifying inactivation of fecal indicator bacteria is the main process to control surf zone water quality during the day. Overall, the analytical model shows a good agreement between predicted and synthetic data (R
2 = 0.51 and 0.67 for FC and ENT, respectively) for the simulated period, amplifying its potential use in the surf zone modelling. It is recommended that when the dimensionless index is much larger than 0.5, the present modified model can predict better than the conventional model, but if index is smaller than 0.5, the conventional model is more efficient with respect to time and cost. [ABSTRACT FROM AUTHOR]- Published
- 2009
- Full Text
- View/download PDF
43. Statistical assessment for spatio-temporal water quality in Angkor, Cambodia.
- Author
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Seo Jin Ki, Joo-Hyon Kang, Young Geun Lee, Yun Seok Lee, Sthiannopkao, Suthipong, and Joon Ha Kim
- Subjects
WATER quality management ,WATER pollution ,STORM drains ,GROUNDWATER ,WATER quality ,SEDIMENTS ,WATER supply ,URBANIZATION - Abstract
Comprehensive water quality monitoring was conducted to assess the water quality conditions and to determine the impact of urban infrastructure on ambient water quality in Angkor, Cambodia. During this study, surface water, groundwater, and sediment samples were collected for two distinctive seasons in 2006-2007 at 58 monitoring sites along and near the Siem Reap River, in Tole Sap Lake (TSL), and West Baray, the primary water resources in this region. To assess the seasonal and spatial variability of 27 water quality parameters, multivariate analysis of variance, hierarchical cluster analysis, and the Kruskal-Wallis test were conducted using the obtained data. Differences and relationships between the surface water and groundwater were also investigated using t-test and correlation analysis, respectively. The results of these tests showed that the bacterial indicators need special attention as the urban infrastructure of the downtown area caused increased levels of these bacterial indicators in both surface water and groundwater. However, for most parameters, though surface water showed strong seasonal variations, groundwater presented relatively stable conditions between seasons ( p > 0.05) with site-specific geochemical conditions. Sediment quality illustrated that pollution levels of 10 trace metals were the highest in TSL because of its unique characteristic (river with backward flow), but did not reflect any potential enrichment from urban development. Overall, the results reveal that while the urban infrastructure in this region has not significantly affected most of the water quality parameters, bacteria and coliphages are still a main concern due to their contributions in widespread waterborne diseases. Thus, careful mitigation plans for reducing each pollutant source are needed in the Angkor area. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
44. Prediction of effluent concentration in a wastewater treatment plant using machine learning models.
- Author
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Hong Guo, Kwanho Jeong, Jiyeon Lim, Jeongwon Jo, Young Mo Kim, Jong-pyo Park, Joon Ha Kim, and Kyung Hwa Cho
- Subjects
- *
MACHINE learning , *SEWAGE disposal plants , *FOOD industrial waste , *WATER quality , *ARTIFICIAL neural networks - Abstract
Of growing amount of food waste, the integrated food waste and waste water treatment was regarded as one of the efficient modeling method. However, the load of food waste to the conventional waste treatment process might lead to the high concentration of total nitrogen (T-N) impact on the effluent water quality. The objective of this study is to establish two machine learning models--artificial neural networks (ANNs) and support vector machines (SVMs), in order to predict 1-day interval T-N concentration of effluent from a wastewater treatment plant in Ulsan, Korea. Daily water quality data and meteorological data were used and the performance of both models was evaluated in terms of the coefficient of determination (R2), Nash-Sutcliff efficiency (NSE), relative efficiency criteria (drel). Additionally, Latin-Hypercube one-factor-at-a-time (LH-OAT) and a pattern search algorithm were applied to sensitivity analysis and model parameter optimization, respectively. Results showed that both models could be effectively applied to the 1-day interval prediction of T-N concentration of effluent. SVM model showed a higher prediction accuracy in the training stage and similar result in the validation stage. However, the sensitivity analysis demonstrated that the ANN model was a superior model for 1-day interval T-N concentration prediction in terms of the cause-and-effect relationship between T-N concentration and modeling input values to integrated food waste and waste water treatment. This study suggested the efficient and robust nonlinear time-series modeling method for an early prediction of the water quality of integrated food waste and waste water treatment process [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
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