The average annual value of COD (chemical oxygen demand) fluxes of the Changjiang River (Yangtze River) and its main tributaries in the past decade (i.e., 1991–2000), has been evaluated. Based on the data from the Da...The average annual value of COD (chemical oxygen demand) fluxes of the Changjiang River (Yangtze River) and its main tributaries in the past decade (i.e., 1991–2000), has been evaluated. Based on the data from the Datong Hydrological Station (DHS), it was found that the Dongting Lake drainage basin contributed the greatest water discharge (35.8%) and COD flux (48.3%) among the main tributary drainage basins, followed by the Poyang Lake drainage basin with the contributions of 15.4% and 19.3%,respectively. By the end of the year of 2000, COD flux in the Changjiang River rose by almost 45% relative to that in the year of 1991, reaching about 1941000 ton/a at DHS. Statistical analysis revealed that industrial wastewater discharge, as well as COD in it, was found decreasing in the same period, due to the gradual reinforcement of environmental management. Moreover, correlation analysis indicated that non-point pollution from agriculture and increasing discharge of domestic sewages caused by rapid growth of population along the Changjiang River drainage valley should be responsible for the high COD. Furthermore, with the current trend of population growth and agricultural development in this basin, water quality of the Changjiang River, in terms of COD level, is going to deteriorate in the near future. Thus, the rational applications of fertilizers and pesticides in agriculture and the proper treatment of domestic sewages before they are discharged would be the most concerned controlling parameters.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
基金Acknowledgements This work is financially supported by the National Natural Science Foundation of China(Grant Nos.40571158,40303013 and 40103008).
文摘The average annual value of COD (chemical oxygen demand) fluxes of the Changjiang River (Yangtze River) and its main tributaries in the past decade (i.e., 1991–2000), has been evaluated. Based on the data from the Datong Hydrological Station (DHS), it was found that the Dongting Lake drainage basin contributed the greatest water discharge (35.8%) and COD flux (48.3%) among the main tributary drainage basins, followed by the Poyang Lake drainage basin with the contributions of 15.4% and 19.3%,respectively. By the end of the year of 2000, COD flux in the Changjiang River rose by almost 45% relative to that in the year of 1991, reaching about 1941000 ton/a at DHS. Statistical analysis revealed that industrial wastewater discharge, as well as COD in it, was found decreasing in the same period, due to the gradual reinforcement of environmental management. Moreover, correlation analysis indicated that non-point pollution from agriculture and increasing discharge of domestic sewages caused by rapid growth of population along the Changjiang River drainage valley should be responsible for the high COD. Furthermore, with the current trend of population growth and agricultural development in this basin, water quality of the Changjiang River, in terms of COD level, is going to deteriorate in the near future. Thus, the rational applications of fertilizers and pesticides in agriculture and the proper treatment of domestic sewages before they are discharged would be the most concerned controlling parameters.
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)).
