浮萍去除污水处理厂出水中氮磷的比较研究

Effects of Duckweed on Nitrogen and Phosphorus Removal in Reclaimed Wastewater

以经筛选得到的本地优化浮萍品种———少根紫萍和稀脉浮萍为供试材料,以扬州某污水处理厂二级出水为供试水,考察了夏季气象条件下两种浮萍对水中氮、磷的去除及其自身积累氮、磷的情况,并作出相应的比较。结果表明:放养稀脉浮萍的水中总氮、总磷的去除量分别是放养少根紫萍的水中总氮、总磷去除量的1.6倍和2.2倍;稀脉浮萍体内积累的氮、磷分别是少根紫萍积累的1.6倍和1.9倍。供试水体中总氮的去除量与浮萍体内氮养分的积累量动态非常类似,但前者明显大于后者,水中氮的去除尚存在其他途径;总磷的去除量与浮萍体内磷养分的积累量动态也十分类似,二者在数量上十分接近,说明水体中磷的去除主要是通过浮萍对磷的吸收来实现的。

Two local species,Lemna perpusilla and Spirodela oligorrhiza were chosen to grow in water taken from the secondary effluent of a wastewater treatment plant in Yangzhou.Removal abilities of total nitrogen（TN） and total phosphorus（TP） as well as retention of nitrogen and phosphorus in these two duckweed species were compared.Results showed that Lemna perpusilla had higher removal efficiency than that of Spirodela oligorrhiza.TN and TP removed by Lemna perpusilla were 1.6 and 2.2 times as those by Spirodela oligorrhiza,while TN and TP retention in Lemna perpusilla were 1.6 and 1.9 times as those in Spirodela oligorrhiza.Dynamics of TN removal and plant retention were similar,but significantly higher TN removal from wastewater were determined than TN in duckweed plants,which implied other possible TN removal strategies might have been involved.Amount of TP removed from wastewater was close to TP in plants,indicating absorption of duckweed as a major pathway of TP removal.