海绵铁和活性氧化铝滤柱净化城市景观水的对比

Purification Effect of Sponge Iron Filter and Activated Alumina Filter on Urban Landscape Water

以再生水为水源的城市景观水体中氮、磷浓度偏高,加上自身净化能力较差,易造成水体富营养化。研究了以海绵铁和活性氧化铝为填料的两个快速滤柱对景观水的净化效果,结果表明,海绵铁滤柱对景观水中TP、PO_4^(3-)-P、叶绿素a(Chl-a)和浊度的去除率均值分别为88.8%、96.2%、73.8%和83.4%;活性氧化铝滤柱对景观水中TP、PO_4^(3-)-P、Chl-a和浊度的去除率均值分别为91.7%、95.4%、66.4%和80.7%。与此同时,海绵铁滤柱虽然对TN有一定的去除,但是零价铁可将进水中的NO_3^-还原为NH_4^+而使出水NH_4^+-N浓度升高,而活性氧化铝滤柱则使出水氨氮浓度降低,尽管其对TN的去除非常有限。此外,海绵铁和活性氧化铝对磷酸盐的Langmuir最大吸附量分别为362和73.8 mg/kg,前者约为后者的4.9倍,表明海绵铁对低浓度磷具有较大的吸附容量,且0.1 mol/L KCl+0.1 mol/L Na OH组合溶液对饱和海绵铁的再生效果良好。

The high concentration of nitrogen and phosphorus in the landscape water supplemented with the reclaimed water and the poor ability of purification easily lead to eutrophication of urban land- scape. The purification effects of sponge iron filter and activated alumina filter on the landscape water were studied. The results showed that the mean removal of TP, PO4^3- - P, Chlorophyll a and turbidity in sponge iron filter were 88.8%, 96.2%, 73.8% and 83.4%, respectively, and those in activated alu- mina filter were 91.7%, 95.4%, 66.4% and 80.7%, respectively. At the same time, the sponge iron filter would increase the NH4 -N concentration in the effluent because the zero-valent iron could reduce NO3- in the influent into NH4＋ , although the TN concentration was lowered by the sponge iron filter. However the activated alumina filter could decrease NH4＋ - N concentration although it had a limited abil- ity to remove TN. In addition, the maximum adsorption capacity of sponge iron and activated alumina through Langmuir curve was 362 mg/kg and 73.8 mg/kg, respectively, which revealed sponge iron had a large adsorption capacity for low concentration of phosphorus. Furthermore, it was also found 0. 1 mol/L KCl ＋ 0. 1 mol/L NaOH had a good effect on the regeneration of saturated sponge iron.