常见基质对暴雨径流中磷素去除效果的比较研究

选取沙子、土壤、沸石、白矾石、陶粒、钢渣、石灰石、蛭石和碎石9种常见的基质,通过吸附和解吸实验、静态吸附实验和动态模拟实验,较为系统地研究了这些基质的吸附特性以及去除暴雨径流中低浓度磷素污染物的特性,并分析了影响基质去除磷素的影响因子.结果表明,9种供试基质对磷酸盐的动态去除效率要比其他形态磷高,对磷素的平衡吸附量大小顺序为：沸石、土壤、蛭石 ＞陶粒、钢渣、石灰石 ＞碎石、沙子、白矾石,对磷素的动态吸附能力为：沸石、石灰石、白矾石、土壤＞钢渣、碎石、沙子＞陶粒、蛭石.另外,蛭石、陶粒和钢渣在对暴雨径流中磷素的静态和动态吸附过程中出现了磷释放现象,其它基质对磷酸盐的动态吸附能力较强,去除率介于30%～87%.综合分析以上多种因素,为了去除暴雨径流中的低浓度磷素,沸石、石灰石和土壤是比较理想的工程基质材料.

Simulation Research on Removal Efficiency of P-pollutants by Several Substrates in Stormwater

9 kinds of substrate materials (gravel, aluminite stone, sands, soil, zeolite, ceramic granule, limestone, steel slag and vermiculite) were selected to examine the phosphorus adsorption and removal capacities from runoff by adsorption, captive test and dynamic adsorption experiments. The results showed that these substrate materials had higher removal efficiency for PO^3-₄ than those of other phosphorus forms. The adsorption characteristics of the substrates could be described by both Freundlich and Langmuir adsorption isotherms. The equilibrium adsorption capacity of these substrates was in the following order: zeolite, soil and vermiculite > ceramic granule, steel slag and limestone > gravel, sands and aluminite stone. The dynamic adsorption capacity was zeolite, soil, limestone and aluminite stone > steel slag, gravel and sands > ceramic granule and vermiculite. In the meanwhile, the releasing phenomena of phosphorus also could be observed in the captive and dynamic test, particularly for vermiculite, ceramic granule and steel slag. In the dynamic adsorption experiment, the removal efficiency of P-pollutants was ranged from 30% to 87% for the substrate materials except vermiculite, ceramic granule and steel slag. The results suggest that zeolite, limestone and soil are appropriate substrates for removing P-pollutants from stormwater.