[ Objective] This study was to research the treatment effect of different media in undercurrent wetland on contamination, so as to pro- vide reference for rehabitating water body of river along small towns. [ Method ]...[ Objective] This study was to research the treatment effect of different media in undercurrent wetland on contamination, so as to pro- vide reference for rehabitating water body of river along small towns. [ Method ] Three different media of gravel, cobblestone and shale were used to rehabilitate water quality of contaminated river. [ Result ] Gravel, cobblestone and shale all performed well in removing TN, TP and CODw,, in contaminated water, of which gravel stuffed undercurrent wetland run best, averagely removing 49.4% TN, 34.7% and 48. 5% COD~, respectively. [ Conclusion] Undercurrent constructed wetland can effectively improve the water quality of contaminated river, and it is cheaper in cost and simpler in operation, thus suitable for generalizing in small towns of China.展开更多
In this work, new composite membranes were successfully prepared via phase inversion technique using polyvinyl chloride(PVC) and polyvinylpyrrolidone(PVP) as polymers and tetrahydrofuran(THF) and N-methyl-2-pyrrolidon...In this work, new composite membranes were successfully prepared via phase inversion technique using polyvinyl chloride(PVC) and polyvinylpyrrolidone(PVP) as polymers and tetrahydrofuran(THF) and N-methyl-2-pyrrolidone(NMP) as solvents. The prepared membranes have been characterized by scanning electron microscope(SEM), and fourier transforms infrared spectroscopy(FTIR). The scanning electron microscope results prove that the prepared membranes are smooth and their pores are distributed throughout the whole surface and bulk body of the membrane without any visible cracks. The stress–strain mechanical test showed an excellent mechanical behavior enhanced by the presence of PVP in the prepared membranes. The membranes performance results showed that the salt rejection reached 98% with a high flux. This, in turn, makes the prepared membranes can be applied for sea and brackish water treatment through membrane distillation technology.展开更多
A systematic strategy for retrofit of the multi-period heat exchanger network （HEN） on the basis of the multi- objective optimization is developed. In this three-stage procedure, a simplified multi-objective optimiz...A systematic strategy for retrofit of the multi-period heat exchanger network （HEN） on the basis of the multi- objective optimization is developed. In this three-stage procedure, a simplified multi-objective optimization model of the multi-period lIEN is first established and then solved to target the retrofit, aiming to minimizing the total annual cost and total annual CO2 emissions. The obtained Pareto front represents series of retrofit targets under different emission limitations, from which the most desirable one can be selected. The matching of the existing and the required heat exchangers is further implemented to finalize the retrofit, which will meet the practical retrofit requirements and matching restrictions. The application of the proposed procedure is illustrated through a case study of a HEN in a vacuum gas oil hydro-treating unit.展开更多
A numerical tool, called Hydro-Geosphere, was used to simulate unsaturated water flow and contaminants migration around an open pit filled with mining wastes. Numerical simulations had been carried out to assess the i...A numerical tool, called Hydro-Geosphere, was used to simulate unsaturated water flow and contaminants migration around an open pit filled with mining wastes. Numerical simulations had been carried out to assess the influence of various factors on water flow and solute transport in and around the surface openings including recharge, properties of the waste material and presence of fractures in the surrounding rock mass. The effect of the regional hydraulic gradient was also investigated. The analyses were conducted by simulating various 2D cases using experimentally obtained material properties and controlled boundary conditions. The effects of the hydrogeological properties of the filling material(i.e., water retention curve and hydraulic conductivity function), fracture network characteristics and conductivity of the joints were assessed. The results illustrate that fractures control water flow and contaminants transport around the waste disposal area. A fracture network can desaturate the system and improve the regional gradient effect.展开更多
文摘[ Objective] This study was to research the treatment effect of different media in undercurrent wetland on contamination, so as to pro- vide reference for rehabitating water body of river along small towns. [ Method ] Three different media of gravel, cobblestone and shale were used to rehabilitate water quality of contaminated river. [ Result ] Gravel, cobblestone and shale all performed well in removing TN, TP and CODw,, in contaminated water, of which gravel stuffed undercurrent wetland run best, averagely removing 49.4% TN, 34.7% and 48. 5% COD~, respectively. [ Conclusion] Undercurrent constructed wetland can effectively improve the water quality of contaminated river, and it is cheaper in cost and simpler in operation, thus suitable for generalizing in small towns of China.
文摘In this work, new composite membranes were successfully prepared via phase inversion technique using polyvinyl chloride(PVC) and polyvinylpyrrolidone(PVP) as polymers and tetrahydrofuran(THF) and N-methyl-2-pyrrolidone(NMP) as solvents. The prepared membranes have been characterized by scanning electron microscope(SEM), and fourier transforms infrared spectroscopy(FTIR). The scanning electron microscope results prove that the prepared membranes are smooth and their pores are distributed throughout the whole surface and bulk body of the membrane without any visible cracks. The stress–strain mechanical test showed an excellent mechanical behavior enhanced by the presence of PVP in the prepared membranes. The membranes performance results showed that the salt rejection reached 98% with a high flux. This, in turn, makes the prepared membranes can be applied for sea and brackish water treatment through membrane distillation technology.
基金Supported by the National Natural Science Foundation of China(21376188,21676211)
文摘A systematic strategy for retrofit of the multi-period heat exchanger network （HEN） on the basis of the multi- objective optimization is developed. In this three-stage procedure, a simplified multi-objective optimization model of the multi-period lIEN is first established and then solved to target the retrofit, aiming to minimizing the total annual cost and total annual CO2 emissions. The obtained Pareto front represents series of retrofit targets under different emission limitations, from which the most desirable one can be selected. The matching of the existing and the required heat exchangers is further implemented to finalize the retrofit, which will meet the practical retrofit requirements and matching restrictions. The application of the proposed procedure is illustrated through a case study of a HEN in a vacuum gas oil hydro-treating unit.
基金financial support of the Natural Sciences and Engineering Research Council of Canada (NSERC)the partners of Research Institute on Mines and the Environment (RIME UQAT-Polytechnique)
文摘A numerical tool, called Hydro-Geosphere, was used to simulate unsaturated water flow and contaminants migration around an open pit filled with mining wastes. Numerical simulations had been carried out to assess the influence of various factors on water flow and solute transport in and around the surface openings including recharge, properties of the waste material and presence of fractures in the surrounding rock mass. The effect of the regional hydraulic gradient was also investigated. The analyses were conducted by simulating various 2D cases using experimentally obtained material properties and controlled boundary conditions. The effects of the hydrogeological properties of the filling material(i.e., water retention curve and hydraulic conductivity function), fracture network characteristics and conductivity of the joints were assessed. The results illustrate that fractures control water flow and contaminants transport around the waste disposal area. A fracture network can desaturate the system and improve the regional gradient effect.
