The inactivation effects of pressurized CO2 against bacteriophage Qβ and ФX 174 were investigated under the pressure of 0.3-0.9 MPa, initial concentration of 107-109 PFU/mL, and temperature of 17.8℃-27.2℃. The opt...The inactivation effects of pressurized CO2 against bacteriophage Qβ and ФX 174 were investigated under the pressure of 0.3-0.9 MPa, initial concentration of 107-109 PFU/mL, and temperature of 17.8℃-27.2℃. The optimum conditions were found to be 0.7 MPa and an exposure time of 25 min. Under identical treatment conditions, a greater than 3.3-log reduction in bacteriophage Qβ was achieved by CO2, while a nearly 3.0 log reduction was observed for phage ФX174. The viricidal effects of N2O （an inactivation gas with similar characteristics to CO2）, normal acid （HC1）, and CO2 treatment with phosphate buffered saline affirmed the chemical nature of CO2 treatment. The pumping cycle, depressurization rate, and release of intracellular substances caused by CO2 were its viricidal mechanisms. The results indicate that CO2 has the potential for use as a disinfectant without forming disinfection by-products.展开更多
A yearlong monitoring program in the backwater area of Xiaojiang River(XBA)was launched in order to investigate the eutrophication of backwater areas in tributaries of the Yangtze River in the Three Gorges Reservoir(T...A yearlong monitoring program in the backwater area of Xiaojiang River(XBA)was launched in order to investigate the eutrophication of backwater areas in tributaries of the Yangtze River in the Three Gorges Reservoir(TGR)in China,starting after the impoundment water level of the TGR reached 156 m.From March 2007 to March 2008,the average concentration of total nitrogen(TN)and total phosphorus(TP)were(1553484)μg·L^(–1)and(6231)μg·L^(–1),respectively.The mean value of chlorophyll was(9.070.91)μg·L^(–1).The trophic level of XBA was meso-eutrophic,while the general nutrient limitation was phosphorus.The results indicated that XBA has a strong ability to purify itself and has non-point source pollution from terrestrial runoff.The variation of TN/TP ratio was caused by a variation in TN rather than in TP when TN/TP<22.N-fixation from cyanobacteria occurred and became an important process in overcoming the nitrogen deficit under a low TN/TP ratio.When TN/TP≥22,the variation of TP affected the TN/TP ratio more significantly than TN.The increase of TP in XBA was caused mainly by particulate phosphorus,which could originate from a non-point source as adsorptive inorganic forms after heavy rainfall and surface runoff.An increase in the river’s flow could also contribute to an unstable environment for the growth of phytoplankton.展开更多
基金supported by a cooperation agreement between Yamaguchi University and the Ministry of Education & Training (Vietnam)
文摘The inactivation effects of pressurized CO2 against bacteriophage Qβ and ФX 174 were investigated under the pressure of 0.3-0.9 MPa, initial concentration of 107-109 PFU/mL, and temperature of 17.8℃-27.2℃. The optimum conditions were found to be 0.7 MPa and an exposure time of 25 min. Under identical treatment conditions, a greater than 3.3-log reduction in bacteriophage Qβ was achieved by CO2, while a nearly 3.0 log reduction was observed for phage ФX174. The viricidal effects of N2O （an inactivation gas with similar characteristics to CO2）, normal acid （HC1）, and CO2 treatment with phosphate buffered saline affirmed the chemical nature of CO2 treatment. The pumping cycle, depressurization rate, and release of intracellular substances caused by CO2 were its viricidal mechanisms. The results indicate that CO2 has the potential for use as a disinfectant without forming disinfection by-products.
基金the Western China Action Program of China Academy of Science(No.KZCX2-XB2-07-02)the Grand S&T Project of Chongqing Municipality(No.CSTC2006BA7030).
文摘A yearlong monitoring program in the backwater area of Xiaojiang River(XBA)was launched in order to investigate the eutrophication of backwater areas in tributaries of the Yangtze River in the Three Gorges Reservoir(TGR)in China,starting after the impoundment water level of the TGR reached 156 m.From March 2007 to March 2008,the average concentration of total nitrogen(TN)and total phosphorus(TP)were(1553484)μg·L^(–1)and(6231)μg·L^(–1),respectively.The mean value of chlorophyll was(9.070.91)μg·L^(–1).The trophic level of XBA was meso-eutrophic,while the general nutrient limitation was phosphorus.The results indicated that XBA has a strong ability to purify itself and has non-point source pollution from terrestrial runoff.The variation of TN/TP ratio was caused by a variation in TN rather than in TP when TN/TP<22.N-fixation from cyanobacteria occurred and became an important process in overcoming the nitrogen deficit under a low TN/TP ratio.When TN/TP≥22,the variation of TP affected the TN/TP ratio more significantly than TN.The increase of TP in XBA was caused mainly by particulate phosphorus,which could originate from a non-point source as adsorptive inorganic forms after heavy rainfall and surface runoff.An increase in the river’s flow could also contribute to an unstable environment for the growth of phytoplankton.
