The elemental composition and bacteria attached in particles were investigated during granular activated carbon （GAC） filtration.The experimental results showed that trapped influent particles could form new,larger ...The elemental composition and bacteria attached in particles were investigated during granular activated carbon （GAC） filtration.The experimental results showed that trapped influent particles could form new,larger particles on GAC surface.The sloughing of individuals off GAC surface caused an increase in effluent particles in the size range from 5 to 25 μm.The selectivity for element removal in GAC filters caused an increasing proportion of metallic elements in the effluent particles.The distribution of molar ratio indicated a complicated composition for large particles,involving organic and inorganic substances.The organic proportion accounted for 40% of total carbon attached to the particles.Compared with dissolved carbon,there was potential for the formation of trihalomethanes by organic carbon attached to particles,especially for those with size larger than 10 μm.The pure carbon energy spectrum was found only in the GAC effluent and the size distribution of carbon fines was mainly above 10 μm.The larger carbon fines provided more space for bacterial colonization and stronger protection for attached bacteria against disinfection.The residual attached bacteria after chorine disinfection was increased to 10 2-10 3 CFU/mL within 24 hours at 25°C.展开更多
Comparative experiments on the inactivation of Copepod were investigated in southern China. The 100% of inactivation effect may be attained by 3.0 mg/L of ozone for contacting time of 25 min, whereas 0.5 mg/L of dosag...Comparative experiments on the inactivation of Copepod were investigated in southern China. The 100% of inactivation effect may be attained by 3.0 mg/L of ozone for contacting time of 25 min, whereas 0.5 mg/L of dosage resulted in only 30% of inactivation rate. Copepod may not be completely inactivated by ozone oxidation for feasible dosage limited by higher bromide in raw water. The favorable environment of granular activated carbon （GAC） filter provided Copepod with conditions for excess propagation, The disinfection experimental results show that the inactivation rate is 90% by 2.0 mg/L of chloramines for contacting time of 30 min, whereas only 70% is attained with chlorine. The GC-MS examination indicates that the total organic substance is increased to 92 specie： inciuding 13 sorts of halogenated hydrocarbon by chlorine disnfection, which is more than that of chloramines. More products of bromiinated trihalomethanes occur in treated water by chlorine, disinfection and total amount of THMs is 3 times as high as that of chloramines.展开更多
基金supported by the National Natural Science Foundation of China (No. 50778062)the Hi-Tech Research and Development Program (863) of China (No.2006AA06Z311)
文摘The elemental composition and bacteria attached in particles were investigated during granular activated carbon （GAC） filtration.The experimental results showed that trapped influent particles could form new,larger particles on GAC surface.The sloughing of individuals off GAC surface caused an increase in effluent particles in the size range from 5 to 25 μm.The selectivity for element removal in GAC filters caused an increasing proportion of metallic elements in the effluent particles.The distribution of molar ratio indicated a complicated composition for large particles,involving organic and inorganic substances.The organic proportion accounted for 40% of total carbon attached to the particles.Compared with dissolved carbon,there was potential for the formation of trihalomethanes by organic carbon attached to particles,especially for those with size larger than 10 μm.The pure carbon energy spectrum was found only in the GAC effluent and the size distribution of carbon fines was mainly above 10 μm.The larger carbon fines provided more space for bacterial colonization and stronger protection for attached bacteria against disinfection.The residual attached bacteria after chorine disinfection was increased to 10 2-10 3 CFU/mL within 24 hours at 25°C.
基金National Natural Science Foundation of China(No.50808065)National Key High-Tech Program(863) of China(No.2006AA06Z311)Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes Open Project,China(No.2006KJ006)
文摘Comparative experiments on the inactivation of Copepod were investigated in southern China. The 100% of inactivation effect may be attained by 3.0 mg/L of ozone for contacting time of 25 min, whereas 0.5 mg/L of dosage resulted in only 30% of inactivation rate. Copepod may not be completely inactivated by ozone oxidation for feasible dosage limited by higher bromide in raw water. The favorable environment of granular activated carbon （GAC） filter provided Copepod with conditions for excess propagation, The disinfection experimental results show that the inactivation rate is 90% by 2.0 mg/L of chloramines for contacting time of 30 min, whereas only 70% is attained with chlorine. The GC-MS examination indicates that the total organic substance is increased to 92 specie： inciuding 13 sorts of halogenated hydrocarbon by chlorine disnfection, which is more than that of chloramines. More products of bromiinated trihalomethanes occur in treated water by chlorine, disinfection and total amount of THMs is 3 times as high as that of chloramines.
