模拟砾石垂直潜流人工湿地的除磷性能分析

摘要

In order to analyse the efficiency of removing phosphorus from wastewater by using gravel as a medium in vertical-flow constructed wetlands, the phosphorus adsorption rate, capacity and mechanism of gravel were examined. The simulative adsorption experiments under static state showed that gravel took fairly short time to get phosphorus adsorption equilibrium at a rather high rate. Along with the temperature going down, the phosphorus adsorption intensity and the dependence of adsorption capacity upon balance concentration increased whilst the maximal stoichiometric adsorption capacity also rose 36% and over. To treat domestic wastewater at strength of 0.5 m3/m~/d, gravel could only remove 20% of total phosphorus by physical adsorption. As the maximal desorption of phosphorus from big- and small-sized gravel wou!d account for 0.21% and 5.08% of the maximal adsorption, respectively, it was necessary to control a risk of the secondary pollution caused by phosphorus desorption from gravel when used as a medium material in vertical-flow constructed wetlands.%为确定砾石作为垂直潜流人工湿地基质的可行性，采用静态吸附实验和砾石去除生活污水中的磷素实验。研究从砾石对污水中磷素污染物的吸附速率、理论吸附量、吸附机理和方式及其二次解析量。结果表明，砾石对污水中磷素的吸附平衡时间较短，吸附速率较快；当温度降低时，砾石的磷素吸附容量对吸附平衡浓度依赖性和吸附强度随之升高，最大理论吸附量亦升高36％以上；在处理0．5m3／（m2·d）的生活污水中，砾石对TP的平均去除率只有20％，吸附方式只有物理吸附；大小粒径的砾石最大磷素解析量分别占最大吸附量的0．21％和5．08％，在实际人工湿地应用中应注意磷素解析而形成的二次污染。