几种挺水植物净化生活污水总氮和总磷效果的研究

研究了石菖蒲、灯心草和蝴蝶花3种不同植被系统、基质为河砂的潜流型人工湿地净化生活污水总氮和总磷的效果,并同无植被系统、相同基质的潜流型人工湿地净化效果进行了比较,结果表明:在较低浓度范围里无植被的人工湿地和3种有植被的人工湿地对污水中总氮有较好的去除作用,随着污水中总氮浓度的增加,虽然无植被的人工湿地和有植被的人工湿地去除总氮的效果均有下降的趋势,但有植被的人工湿地仍然能维持较高的总氮去除水平,无植被的人工湿地总氮去除效果则下降较快。在有植被的人工湿地中,以石菖蒲植被人工湿地氮素净化能力最强,其次为灯心草和蝴蝶花,这与植被自身吸收同化污水中氮素水平以及植物根系微生物作用有关。对于污水中总磷的去除,本研究中由于污水中磷素浓度较低,无植被和有植被的人工湿地对污水中磷素均有很好的去除作用,没有明显差异,但不同的植物体中磷素仍有明显的吸收同化富集现象,其中石菖蒲吸收同化磷素能力最强,其次为蝴蝶花和灯心草,植被在人工湿地系统中对于污水中总氮和总磷的去除起着重要的作用。

Study on Purified Efficiency of Phosphorus and Nitrogen from Domestic Sewage by Several Macrophytes in Vertical Flow Constructed Wetlands

In order to investigate macrophyte role on the waster water purification and select appropriate native vegetable to built plant filter in constructed wetland, four vertical flow constructed wetlands with river sand as their substrates were made. Among them, number 1 had Grassleaved Sweetflag(Acorus gramineus Soland.), number 2 had Rush (Juncus effucus Linn), number 3 had Butterfly Swordflag(Iris japonica Thunb.), and number 4 had no vegetable (CK). Within lower concentration of total nitrogen (TN) (<30 mg/L), the constructed wetlands with or without macrophytes had better effects on removal TN form domestic sewage and had little difference in treatment efficiency. When concentration of TN increased, the purified efficiency of all constructed wetlands had decreased to some extent. The constructed wetlands with vegetable remained higher efficiency than that constructed wetland without vegetable in purification of TN in treatment waster water. Among the constructed wetlands with vegetables, Number 1 had higher purified efficiency of TN than number 2 and number3. For total phosphorus (TP) removal, all of constructed wetlands had a good performance on removal of phosphorus form domestic sewage due to lower concentration of phosphorus in domestic sewage (<20 mg/L). Although substrates were unsaturated with phosphorus, the vegetable had yet absorbed more phosphorus. Of all vegetables, Grassleaved Sweetflag had a better ability to clean phosphorus than Butterfly Swordflag and Rush. The biomass and content of nitrogen, phosphorus in vegetable body were the main factors affected the ability of vegetable on cleaning nitrogen and phosphorus form waster water, because the vegetable absorbs nitrogen and phosphorus as its physical need during its growth. Besides nitrogen absorption, the nitrification and denitrification led by microorganism around root can enhance the wetland performance on removal nitrogen form domestic sewage. The vertical flow constructed wetland is better instrument for treating waster water with lower concentration of pollutants and should be widely used in the future.