植物吸收在人工湿地脱氮除磷中的贡献

通过研究人工湿地植物对氮、磷的吸收能力,评价植物吸收在人工湿地脱氮除磷方面的贡献.结果表明,不同湿地植物其组织中W(TN)和W(TP)差异极显著,湿地植物对TN和TP的吸收量分别为6.1～94.0和0.5～9.0 g/(m2·a).按全年衡算,湿地植物对TN和TP的吸收量分别占人工湿地TN和TP去除量的0.6%～17.3%和1.4%～41.2%.但由于湿地植物吸收的TN和TP中有相当一部分是储存在湿地植物的地下部,通过收获植物地上部的TN和TP吸收量仅占人工湿地TN和TP去除量的0.3%～14.1%和0.8%～19.6%.由此可见,湿地植物的直接吸收在人工湿地系统氮、磷去除中不占重要地位,人工湿地植物的选择和利用应该更注重其间接生态效应的发挥.

Contribution of Macrophytes Assimilation in Constructed Wetlands to Nitrogen and Phosphorous Removal

Macrophyte nitrogen and phosphorous assimilation and its contribution in constructed wetlands (CWs) to nitrogen and phosphorous removal were assessed in this paper. The results showed that the contents of total nitrogen (TN) and total phosphorous (TP) were significantly different among the macrophytes. TN andTP absorption of macrophytes varies from 6.1 to 94.0 g/(m²·a) and from 0.5 to 9.0 g/(m²·a), respectively. Based on nutrient balance in an entire year, only 0.6%-17.3% of TN and 1.4%-41.2% TP were uptaken by macrophytes compared with TN and TP removal by CWs. However, due to a considerable portion of TN and TP which macrophytesabsorbed was stored in the biomass of under-ground, only 0.3%-14.1% of TN and 0.8%-19.6% TP were removed by harvesting the macrophytes (above-ground biomass) compared with TN and TP removal by CWs. This shows that the macrophyte nitrogen and phosphorous assimilation could not play an important role for nutrient removal in CWs. More attention should be paid to the selection and utilization of macrophytes and their other ecological effects.