Volume 5 Issue 2
Authors: Pramod Kumar Sharma; Sourabh Kakani; Sanjay Kumar Shukla
Abstract: This paper presents solute concentration profiles with constant, linear and exponential distance-dependent dispersion models for solute transport through fractured porous rock matrices. A numerical analysis has been developed for solution of the equations governing the dispersion model using the hybrid finite volume method. The results of the numerical analysis have been used to investigate the effect of the matrix diffusion coefficient, fracture velocity, and matrix and fracture retardation factors on concentration profiles. It is found that in the presence of higher matrix diffusion coefficients, the behaviour of concentration profiles is different for constant and distance-dependent dispersion models. However, the behaviour of concentration profiles is observed to be nonlinear during the small transport time period, and the matrix diffusion is found to control the spreading of solute in the fracture in the presence of constant and distance-dependent dispersion models.
Keywords: Fractured Rocks; Numerical Solution; Distance-dependent Dispersion; Concentration Profiles
Authors: Yi-Tze Tsai; Yung-Hsu Hsieh; Chiung-Ta Wu; Yi-Ying Li; Kai-Yuan Cheng; Ta-Lun Sung; Chen-Yu Chang
Abstract: Interest in pollution issues caused by synthetic dye wastewater is growing. For many years, researchers have attempted to develop more efficient treatment technology to solve this long-standing environmental problem. As many related studies have focused on advanced oxidation processes (AOPs), the plasma process is remarkable due to its high decolorization efficiency over a short time. This study applied a plasma process in the form of pulsed discharge to treat dye wastewater and to investigate the decolorization of dye wastewater over time by manipulating operation parameters. This method is expected to provide a rapid and highly efficient decolorization technology for wastewater treatment. The results indicate that 99%, 98%, 95% and 73% decolorization could be achieved for methylene blue solutions with initial concentrations of 1 ppm, 5 ppm, 10 ppm, and 20 ppm, respectively, after the experimental device was operated for one hour with operation parameters set at 100 mL min-1 for air inflow, an initial pH of 2.5 for pollutants, and 10 KV for output voltage, while other parameters were fixed.
Keywords: Advanced Oxidation Processes (AOPs); Plasma Processes; Methylene Blue (MB); Decolorization
Authors: KyuHo KIM; ByungSik KIM; SangHwa JUNG; Il HONG
Abstract: The quantity and timing of runoff are critical components for the water supply, water quality, and ecological interaction of river systems (Poff, et al., 1997). Five components of the flow regime (magnitude, frequency, duration, timing, and rate of change) can directly and indirectly impact an aquatic ecosystem. (Karr, 1991; Poff, et al., 1997). Due to the recent phenomenon of climate change, the timing and pattern of rainfall has changed and affected the flow regime of certain basins. Hence, in this research, the future impact of climate change on the river flow regime and aquatic ecosystem of the Mangyeong River, a medium-sized basin in Korea, has been quantified by analysis of environmental flow components and physical habitat modeling. Consequently, it is predicted that there will be crucial changes in the material conditions related to the river flow regime, and the risk of ecological environmental changes will greatly increase.
Keywords: Climate Change; EFCs; CSI; Environmental Flow Components