水生植物对不同氮磷水平养殖尾水的综合净化能力比较

Comparison of purification ability of aquatic plants under different concentrations of nitrogen and phosphorus in tailrace of livestock wastewater

为了筛选适用于不同氮磷浓度畜禽养殖尾水的生态浮岛优势物种,选取水芹、凤眼莲、鸢尾、再力花、黄菖蒲5种挺水植物和狐尾藻、伊乐藻、金鱼藻3种沉水植物,通过模拟实验考察了这8种植物在不同氮磷浓度条件下的生长特征及其对水中氨氮(NH4^+-N)、总磷(TP)、COD的去除效率,并对其进行曲线回归及主成分分析,综合评价不同水生植物对畜禽养殖废水中氮磷的净化功能。结果表明:凤眼莲、再力花在较低氮磷水平(NH4^+-N 80~120 mg·L^-1,TP 8~16 mg·L^-1)下的去除能力明显高于其他水生植物;水芹和黄菖蒲在较高氮磷水平(NH4^+-N 180~220 mg·L^-1,TP 30~35 mg·L^-1)下的去除效果较好,并具有良好的适应能力;沉水植物中狐尾藻净化效果较好,生物量增长显著(P<0.05);凤眼莲在实验过程中虽净化能力良好,但易引发次生环境问题,应谨慎选择,因地制宜。

In order to screen the dominant species of ecological floating island suitable for different concentrations of nitrogen and phosphorus in tailrace of livestock and poultry wastewater,5 kinds of effluents,such as Oenanthe javanica,Eichhornia crassipes,Iris sibirica,Thalia dealbata,and Iris pseudacorus and 3 kinds of submerged plants,such as Myriophyllum verticillatum,Elodea nuttallii,and Ceratophyllum demersum were selected.The growth characteristics of these 8 plants under different concentrations of nitrogen and phosphorus and their removal efficiency of ammonia nitrogen,total phosphorus,and chemical oxygen demand(COD)in water were investigated using simulation experiments.Curve regression and Principal Component Analysis were carried out to obtain the comprehensive evaluation of plant purification function.Results showed that the removal ability of Eichhornia crassipes and Thalia dealbata was significantly higher than that of other aquatic plants at low concentration of nitrogen and phosphorus(NH4^+-N:80~120 mg·L^-1,TP:8~16 mg·L^-1).Oenanthe javanica and Iris pseudacorus had significant advantages in removing high concentration of nitrogen and phosphorus(NH4^+-N:180~220 mg·L^-1,TP:30~35 mg·L^-1)and also had good adaptability.Myriophyllum verticillatum had better purification effect on submerged plants,and its biomass increased significantly(P<0.05).Although Eichhornia crassipes has good purification capacity,it can easily cause secondary environmental problems;therefore,it is advisable to choose carefully and adjust measures according to local conditions.