Diep Dinh Phong | Sejong University (original) (raw)
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Papers by Diep Dinh Phong
Separation Science and Technology, Oct 30, 2009
Environmental Technology, Jun 1, 2008
A hydrogenotrophic denitrification system with a hollow fiber membrane was evaluated for treating... more A hydrogenotrophic denitrification system with a hollow fiber membrane was evaluated for treating and recycling synthetic aquaculture wastewater. Hollow fibers ensured bubble-less diffusion of hydrogen and subsequent removal of nitrate from the first bioreactor. The second aerobic reactor was used for biomass filtration and removal of organic matter. Nitrate and organic matter expressed as dissolved organic carbon were 50 mgl(-1) and 20 mgl(-1), respectively, in the inlet. Acclimatization of hydrogenotrophic bacteria to 10, 20 and 30 ppt of salinity was also observed. Optimum hydraulic retention time and denitrification rate corresponding to these salinities were 3, 5 and 6 h and 366.8, 226.2 and 193.2 gm(-3) day(-1), respectively.
Social Science Research Network, 2021
Materials Chemistry and Physics
Environmental Science and Pollution Research, 2014
Selected water quality parameters and spectroscopic characteristics of dissolved organic matter (... more Selected water quality parameters and spectroscopic characteristics of dissolved organic matter (DOM) were examined during two different seasons for an artificial coastal lake (Shiwha Lake in South Korea), which are affected by seawater exchange due to the operation of a tidal power plant and external organic loadings from the upstream catchments. The coastal lake exhibited much lower concentrations of organic matter and nutrients than the upstream sources. The spectroscopic properties of the lake DOM were easily distinguished from those of the catchment sources as revealed by a lower absorption coefficient, lower degree of humification, and higher spectral slopes. The observed DOM properties suggest that the lake DOM may be dominated by smaller molecular size and less condensed structures. For the lake and the upper streams, higher absorption coefficients and fluorescence peak intensities but lower spectral slopes and humification index were found for the premonsoon versus the monsoon season. However, such seasonal differences were less pronounced for the industrial channels in the upper catchments. Three distinctive fluorophore groups including microbial humic-like, tryptophan-like, and terrestrial humic-like fluorescence were decomposed from the fluorescence excitation-emission matrix (EEM) of the DOM samples by parallel factor analysis (PARAFAC) modeling. The microbial humic-like component was the most abundant for the industrial channels, suggesting that the component may be associated with anthropogenic organic pollution. The terrestrial humic-like component was predominant for the upper streams, and its relative abundance was higher for the rainy season. Our principal component analysis (PCA) results demonstrated that exchange of seawater and seasonally variable input of allochthonous DOM plays important roles in determining the characteristics of DOM in the lake.
Environmental Science and Technology, Jan 5, 2018
Academia Journal of Biology
In this study, 19 surface bioclimatic variables of high spatial resolution 0.00226o (~ 250 m) are... more In this study, 19 surface bioclimatic variables of high spatial resolution 0.00226o (~ 250 m) are generated in a Geographic Information System by the combination of (1) the raster dataset of monthly temperature and precipitation obtained from the global WorldClim database at 0.00833o spatial resolution for the period of 1960–2000; and (2) the climate data (temperature and precipitation) of the Central Highlands and Southern Central Coast collected from the 31 temperature and 97 precipitation recording sites for the period of 1991–2015. The statistical downscaling method is applied, using multiple linear regression analysis, in which elevation, geographic coordinates, and distance from the coast are treated as independent variables, to estimate the distribution of temperature; and the B-Spline interpolation method combined with multiple linear regression analysis is employed on precipitation over the study area. The outcomes of the two main analyses are computed to create 19 high spa...
Water research, Jan 15, 2016
Non-catalytic and catalytic photodegradation of effluent dissolved organic matter (EfDOM) was exa... more Non-catalytic and catalytic photodegradation of effluent dissolved organic matter (EfDOM) was examined under two different light sources (UVA and UVC). The degradation behavior was tracked by dissolved organic carbon (DOC), UV absorbance, and different fluorescent components. Catalytic UV irradiation resulted in much higher degradation rates than those without photocatalysts (TiO2 and ZnO) regardless of the tracking variables. For non-catalytic degradation, the highest removal rates of UV absorbance were found at wavelengths close to the irradiation of either UVC or UVA, while the photocatalytic degradation rates were consistently higher at longer wavelengths. The pseudo first-order rates of UV absorbance individually calculated at several representative wavelengths were very consistent with the sequential orders interpreted from two-dimensional correlation spectroscopy (2D-COS). Excitation emission matrix - parallel factor analysis (EEM-PARAFAC) identified one tryptophan-like (C1) ...
i Acknowledgments First of all, the author would like to express his profound gratitude, great ap... more i Acknowledgments First of all, the author would like to express his profound gratitude, great appreciation and indebtedness to his advisor, Prof. C. Visvanathan, for his advice, valuable suggestions, and continued encouragement during the whole thesis period. Moreover, Prof. C. Visvanathan has guided me to the positive and critical thinking in professional life. Words of appreciation and grateful acknowledgement are extended to Dr. Jega V. Jegatheesan for his expert guidance, stimulating ideas and serving as a member of examination committee. I wish to express sincere thanks to examination committee members, Dr. Nguyen Thi Kim Oanh and Dr. Oleg Shipin for their valuable comments and suggestions that helped to achieve objectives of this thesis. The author is very grateful to Dr. Porntip Sridang, Prince of Songkla University, Thailand for her valuable comment and suggestion. Thanks also extend to Mr. Bui Xuan Thanh, Ms.
Separation Science and Technology, Oct 30, 2009
Environmental Technology, Jun 1, 2008
A hydrogenotrophic denitrification system with a hollow fiber membrane was evaluated for treating... more A hydrogenotrophic denitrification system with a hollow fiber membrane was evaluated for treating and recycling synthetic aquaculture wastewater. Hollow fibers ensured bubble-less diffusion of hydrogen and subsequent removal of nitrate from the first bioreactor. The second aerobic reactor was used for biomass filtration and removal of organic matter. Nitrate and organic matter expressed as dissolved organic carbon were 50 mgl(-1) and 20 mgl(-1), respectively, in the inlet. Acclimatization of hydrogenotrophic bacteria to 10, 20 and 30 ppt of salinity was also observed. Optimum hydraulic retention time and denitrification rate corresponding to these salinities were 3, 5 and 6 h and 366.8, 226.2 and 193.2 gm(-3) day(-1), respectively.
Social Science Research Network, 2021
Materials Chemistry and Physics
Environmental Science and Pollution Research, 2014
Selected water quality parameters and spectroscopic characteristics of dissolved organic matter (... more Selected water quality parameters and spectroscopic characteristics of dissolved organic matter (DOM) were examined during two different seasons for an artificial coastal lake (Shiwha Lake in South Korea), which are affected by seawater exchange due to the operation of a tidal power plant and external organic loadings from the upstream catchments. The coastal lake exhibited much lower concentrations of organic matter and nutrients than the upstream sources. The spectroscopic properties of the lake DOM were easily distinguished from those of the catchment sources as revealed by a lower absorption coefficient, lower degree of humification, and higher spectral slopes. The observed DOM properties suggest that the lake DOM may be dominated by smaller molecular size and less condensed structures. For the lake and the upper streams, higher absorption coefficients and fluorescence peak intensities but lower spectral slopes and humification index were found for the premonsoon versus the monsoon season. However, such seasonal differences were less pronounced for the industrial channels in the upper catchments. Three distinctive fluorophore groups including microbial humic-like, tryptophan-like, and terrestrial humic-like fluorescence were decomposed from the fluorescence excitation-emission matrix (EEM) of the DOM samples by parallel factor analysis (PARAFAC) modeling. The microbial humic-like component was the most abundant for the industrial channels, suggesting that the component may be associated with anthropogenic organic pollution. The terrestrial humic-like component was predominant for the upper streams, and its relative abundance was higher for the rainy season. Our principal component analysis (PCA) results demonstrated that exchange of seawater and seasonally variable input of allochthonous DOM plays important roles in determining the characteristics of DOM in the lake.
Environmental Science and Technology, Jan 5, 2018
Academia Journal of Biology
In this study, 19 surface bioclimatic variables of high spatial resolution 0.00226o (~ 250 m) are... more In this study, 19 surface bioclimatic variables of high spatial resolution 0.00226o (~ 250 m) are generated in a Geographic Information System by the combination of (1) the raster dataset of monthly temperature and precipitation obtained from the global WorldClim database at 0.00833o spatial resolution for the period of 1960–2000; and (2) the climate data (temperature and precipitation) of the Central Highlands and Southern Central Coast collected from the 31 temperature and 97 precipitation recording sites for the period of 1991–2015. The statistical downscaling method is applied, using multiple linear regression analysis, in which elevation, geographic coordinates, and distance from the coast are treated as independent variables, to estimate the distribution of temperature; and the B-Spline interpolation method combined with multiple linear regression analysis is employed on precipitation over the study area. The outcomes of the two main analyses are computed to create 19 high spa...
Water research, Jan 15, 2016
Non-catalytic and catalytic photodegradation of effluent dissolved organic matter (EfDOM) was exa... more Non-catalytic and catalytic photodegradation of effluent dissolved organic matter (EfDOM) was examined under two different light sources (UVA and UVC). The degradation behavior was tracked by dissolved organic carbon (DOC), UV absorbance, and different fluorescent components. Catalytic UV irradiation resulted in much higher degradation rates than those without photocatalysts (TiO2 and ZnO) regardless of the tracking variables. For non-catalytic degradation, the highest removal rates of UV absorbance were found at wavelengths close to the irradiation of either UVC or UVA, while the photocatalytic degradation rates were consistently higher at longer wavelengths. The pseudo first-order rates of UV absorbance individually calculated at several representative wavelengths were very consistent with the sequential orders interpreted from two-dimensional correlation spectroscopy (2D-COS). Excitation emission matrix - parallel factor analysis (EEM-PARAFAC) identified one tryptophan-like (C1) ...
i Acknowledgments First of all, the author would like to express his profound gratitude, great ap... more i Acknowledgments First of all, the author would like to express his profound gratitude, great appreciation and indebtedness to his advisor, Prof. C. Visvanathan, for his advice, valuable suggestions, and continued encouragement during the whole thesis period. Moreover, Prof. C. Visvanathan has guided me to the positive and critical thinking in professional life. Words of appreciation and grateful acknowledgement are extended to Dr. Jega V. Jegatheesan for his expert guidance, stimulating ideas and serving as a member of examination committee. I wish to express sincere thanks to examination committee members, Dr. Nguyen Thi Kim Oanh and Dr. Oleg Shipin for their valuable comments and suggestions that helped to achieve objectives of this thesis. The author is very grateful to Dr. Porntip Sridang, Prince of Songkla University, Thailand for her valuable comment and suggestion. Thanks also extend to Mr. Bui Xuan Thanh, Ms.