A combined numerical model for computing mixing areas of pollution vertical jet discharging into tidal flows has been developed. This numerical model is composed of a 2-D depth-averaged dynamic far-field numerical mod...A combined numerical model for computing mixing areas of pollution vertical jet discharging into tidal flows has been developed. This numerical model is composed of a 2-D depth-averaged dynamic far-field numerical model and a 2-D vertical dynamic near-field numerical model. The former uses finite node method to compute velocity, and improved finite node method to compute pollutant concentration distribution; the latter is a k-e turbulence model, and uses SIMPLE (Semi-Implicit Method for Pressure Linked Equations) method to compute velocity. At the same time, the former provides boundary conditions for the latter. This model can simulate both far- field pollutant concentration distribution and near-field vertical recirculation quickly and precisely. This model has been verified by measured data of pollutant F of the Dachang reach of the Changjing River and test data presented by Chen el al. (1992). On the basis of verification, the authors use a designed hydrograph to compute this mixing area for a certain amount of wastewater discharging into the river.展开更多
A 2-D vertical dynamic near-field numerical model is developed for the simulation of a vertical jet discharging into tidal flows. This model is a k-εturbulent model. The semi-implicit method for pressure-linked equat...A 2-D vertical dynamic near-field numerical model is developed for the simulation of a vertical jet discharging into tidal flows. This model is a k-εturbulent model. The semi-implicit method for pressure-linked equations is used to solve all the governing equations, which are discretized by control volume method. The model has been tested by water channel experiments. On this basis, the designed hydrological condition for one plan of wastewater of the Dachang district discharging into the Changjiang River has been obtained by this model.展开更多
This paper describes the feasibility of fresh leachate treatment by an upflow blanket filter(UBF).Through dilution and partial effluent recycling,the organic loading rates increased from 0.51 to 14.56 kg COD/(m^(3)...This paper describes the feasibility of fresh leachate treatment by an upflow blanket filter(UBF).Through dilution and partial effluent recycling,the organic loading rates increased from 0.51 to 14.56 kg COD/(m^(3)·d),meanwhile the corresponding hydraulic retention time decreased from 9.0 to 3.6 d.The reactor was able to achieve steady-state within 80 d.Based on the distribution of COD fluxes in the process,it was concluded that anabolism was the main pathway of COD removal in the initial phase(1–33 d),accounting for 57%–85%of total COD removed.As the anaerobic consortium of bacteria reached steady-state(after 70–86 d),the majority of COD removed was transformed into methane,because the specific methane yield was close to the theoretical value(0.36 L CH4/(g CODdeg)).展开更多
文摘A combined numerical model for computing mixing areas of pollution vertical jet discharging into tidal flows has been developed. This numerical model is composed of a 2-D depth-averaged dynamic far-field numerical model and a 2-D vertical dynamic near-field numerical model. The former uses finite node method to compute velocity, and improved finite node method to compute pollutant concentration distribution; the latter is a k-e turbulence model, and uses SIMPLE (Semi-Implicit Method for Pressure Linked Equations) method to compute velocity. At the same time, the former provides boundary conditions for the latter. This model can simulate both far- field pollutant concentration distribution and near-field vertical recirculation quickly and precisely. This model has been verified by measured data of pollutant F of the Dachang reach of the Changjing River and test data presented by Chen el al. (1992). On the basis of verification, the authors use a designed hydrograph to compute this mixing area for a certain amount of wastewater discharging into the river.
文摘A 2-D vertical dynamic near-field numerical model is developed for the simulation of a vertical jet discharging into tidal flows. This model is a k-εturbulent model. The semi-implicit method for pressure-linked equations is used to solve all the governing equations, which are discretized by control volume method. The model has been tested by water channel experiments. On this basis, the designed hydrological condition for one plan of wastewater of the Dachang district discharging into the Changjiang River has been obtained by this model.
基金the National High-Tech Research and Development Program(863 Program)of China(Grant No.2008AA062101)the Key Project of Chinese Ministry of Education(No.107122)。
文摘This paper describes the feasibility of fresh leachate treatment by an upflow blanket filter(UBF).Through dilution and partial effluent recycling,the organic loading rates increased from 0.51 to 14.56 kg COD/(m^(3)·d),meanwhile the corresponding hydraulic retention time decreased from 9.0 to 3.6 d.The reactor was able to achieve steady-state within 80 d.Based on the distribution of COD fluxes in the process,it was concluded that anabolism was the main pathway of COD removal in the initial phase(1–33 d),accounting for 57%–85%of total COD removed.As the anaerobic consortium of bacteria reached steady-state(after 70–86 d),the majority of COD removed was transformed into methane,because the specific methane yield was close to the theoretical value(0.36 L CH4/(g CODdeg)).
