The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes...The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes of organic carbon contents and ammonia concentration at different media height was got. The results showed that as a down flow BAF with granular media, the active layer of nitrifiers was deeper than heterotrophs in BAF. And the optimum media height for the removal of SS, COD Cr and NH + 4-N was 40 cm,60 cm and 80 cm respectively. The removal efficiency of SS, COD Cr and NH + 4-N was 79.1%, 63.9% and 96.4% respectively under the influent COD Cr and NH + 4-N of 122.1 mgCOD Cr /L and 14.84 mgNH + 4-N/L, the influent flux of 15.8 L/h, air to liquid ratio of 3∶1.展开更多
A novel type of solid phase extraction element named“Magic Chemisorber” is developed for sorptive enrichment of dilute analytes from aqueous samples with high extraction efficiencies due to its capacious layer of so...A novel type of solid phase extraction element named“Magic Chemisorber” is developed for sorptive enrichment of dilute analytes from aqueous samples with high extraction efficiencies due to its capacious layer of sorbent polydimethylsiloxane.This extraction element combined with thermal desorption gas chromatography/mass spectrometry using a pyrolysis GC/MS system was applied to extract the pesticides from water samples over a concentration range of 10 -3 to 10 3 μg·l -1 .The method showed good li nearity for the tested concentration range with regression coefficients of 0 995 for over 5 decades.Limits of detection at a sub ng·l -1 (ppt)level were achieved and the reproducibility of the measurements was found to be fairly good,with relative standard deviation below 8%.展开更多
文摘The optimum media height of carbon oxidation and nitrification in a down-flow biological aerated filter was determined, and the distribution of the heterotrophic and nitrifying populations through studying the changes of organic carbon contents and ammonia concentration at different media height was got. The results showed that as a down flow BAF with granular media, the active layer of nitrifiers was deeper than heterotrophs in BAF. And the optimum media height for the removal of SS, COD Cr and NH + 4-N was 40 cm,60 cm and 80 cm respectively. The removal efficiency of SS, COD Cr and NH + 4-N was 79.1%, 63.9% and 96.4% respectively under the influent COD Cr and NH + 4-N of 122.1 mgCOD Cr /L and 14.84 mgNH + 4-N/L, the influent flux of 15.8 L/h, air to liquid ratio of 3∶1.
文摘A novel type of solid phase extraction element named“Magic Chemisorber” is developed for sorptive enrichment of dilute analytes from aqueous samples with high extraction efficiencies due to its capacious layer of sorbent polydimethylsiloxane.This extraction element combined with thermal desorption gas chromatography/mass spectrometry using a pyrolysis GC/MS system was applied to extract the pesticides from water samples over a concentration range of 10 -3 to 10 3 μg·l -1 .The method showed good li nearity for the tested concentration range with regression coefficients of 0 995 for over 5 decades.Limits of detection at a sub ng·l -1 (ppt)level were achieved and the reproducibility of the measurements was found to be fairly good,with relative standard deviation below 8%.
