基质吸附是人工湿地磷去除的主要途径,吸附能力易受环境条件的影响,为了探讨人工湿地运行时内部多样化理化环境对基质磷吸附的影响,以相同基质的无植物和有植物水平潜流人工湿地实验系统为对象,在对人工配制有机污水进行5个月处理后,分析了2个系统不同区域基质中总磷及各主要无机态磷的含量.结果表明,植物系统各部分基质中总磷含量呈现较大的差异,总磷最高的进水区根际基质达0.75 g·kg^-1,其次是进水区抖落和出水区根际基质,最低的出水区非根际基质只有0.21 g·kg^-1,无植物系统各部分基质总磷含量比较接近,在0.21~0.27 g·kg^-1之间,总体来看,植物系统基质总磷含量高于无植物系统;与实验前相比,两系统各部分基质中铁磷、铝磷和钙磷含量都升高,是基质吸附无机磷的主要赋存形式,铁磷和铝磷在两系统不同区域基质中变化特点相似,植物系统进水区根际、抖落基质铁磷、铝磷含量大幅增加,而出水区和无植物系统各部分增加量相对较少;两系统各部分基质钙磷含量升高相对较均衡,但植物系统进水区和出水区根际基质含量也略高于其他部分;两系统各部分基质松散结合态磷和闭蓄态磷含量都比较低;植物根系对基质磷含量具有明显影响,总磷、铁磷、铝磷、钙磷和松散结合态磷含量呈现距离植物根系越近含量越高的特点.
Adsorption of substrate is the main removal mechanisms of phosphorus in constructed wetland.It is easily impacted by various environmental factors existing in the wetland bed.The contents of substrate TP and the main inorganic P in different areas of both horizontal sub-surface flow constructed wetland with plant and one without plant were measured after treating wastewater five months.Different areas of the wetland with plant differed greatly in the substrate TP.Rhizosphere substrate in front area had the highest TP content and achieved 0.75 g·kg^-1,and the TP content of non-rhizosphere substrate in back area was only 0.21 g·kg^-1.The TP content of substrate in different areas of the wetland without plant had a little variety and ranged only between 0.21 and 0.27 g·kg^-1.Averagely,the substrate TP content in the wetland with plant was higher than the one in the wetland without plant.The phosphorous with Fe-bound(Fe-P),Al-bound(Al-P),and Ca-bound(Ca-P) were main inorganic phosphorous existing in the substrate in both wetlands,their contents in different areas substrate all increased,compared with the one before experiment.Fe-P and Al-P in different substrates in both wetlands had a similar variety.Their content between rhizosphere and intermediate substrate of front area in the wetland with plant and other area substrate in both wetlands differed greatly because the former increased greatly.Compared with Fe-P and Al-P,the variety of Ca-P in different substrates in both wetlands was low.But the content of Ca-P in rhizosphere substrate in wetland with plant was higher than other two parts respectively in front and back areas.Obviously,the plant root had an impact on the phosphorous content of substrate in constructed wetland.For TP,Fe-P,Al-P,Ca-P and loosely sorbed phosphorous in substrate,it increased with distance of the root.