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.
通过扫描电镜和能谱分析（Scanning Electron Microscope and Energy Dispersive Analysis，SEM—EDS）对饮用水活性炭工艺出水中的颗粒物进行成分组成分析，考察颗粒物的分布特征及其中主要元素的概率分布，并分析活性炭工艺出水颗粒物中单元素的可能组成形态。结果表明，活性炭进出水中颗粒物所含元素较多，其中以Ca、Fe、Al、Si、C、O为主，且非金属元素的比例明显高于金属元素；颗粒物微观形态丰富，形状多以不规则为主，球形体、絮状集合体和棒状集合体相对较少；（C＋O）／（Ca＋Fe＋Al＋Mg）摩尔比值为1．0～40，其间跨度较大，所测8个样品中，2个样品摩尔比在1．0～3．0，5个样品在7．0以上。
