植物收割对人工湿地中污染物去除的长期影响

Long-term Effect of Plant Harvesting on Pollutants Removal in Constructed Wetlands

通过2组大型人工湿地5年的平行实验,开展了植物收割对人工湿地净化效果影响机制的研究。结果表明,收割人工湿地对TN、NH4^+-N、TP、PO4^3--P的去除率(40.0%、56.6%、35.7%、39.4%)显著高于未收割人工湿地(34.6%、51.0%、29.1%、29.5%);收割人工湿地中植物的生长密度(240株/m^2)、生物量(2.2 kg/m^2)及其对氮、磷的吸收量(60.8、5.7 g/m^2)均高于未收割人工湿地(108株/m^2、0.9 kg/m^2、24.6 g/m^2、2.4 g/m^2);每年收割不仅能够促进人工湿地中植物的直接作用,还能促进植物的间接作用和人工湿地基质层对污染物的去除能力,进而提高人工湿地的脱氮除磷效果。

The effects of plant harvesting on the purification efficacy of constructed wetlands(CWs) was investigated based on 5 a parallel experiments of two large pilot CWs. The results showed that the removal rate of TN, NH4^+-N, TP and PO4^3--P(40.0%, 56.6%, 35.7% and 39.4% respectively) in harvested CWs were significantly higher than that in unharvested CWs(34.6%, 51.0%, 29.1% and 29.5% respectively). The density(240 shoots/m2),aboveground plant biomass(2.2 kg/m^2) and the amount of nitrogen and phosphorus uptake by plants(60.8 g/m^2, 5.7 g/m^2) in the harvested CWs were much higher than that of the unharvested CWs(108 shoots/m^2, 0.9 kg/m^2, 24.6 g/m^2, 2.4 g/m^2). Harvesting could not only promote the direct roles of plants in CWs, but also promote the indirect roles of plants and pollutants removal ability of CWs substrate, and then improve the nitrogen and phosphorus removal performance of CWs.