A Research on Phosphorus Removal in Float System with Different Aquatic Plants from Eutrophic Water of Into-Lake River for Dianchi Lake

Using aquatic plants to purify eutrophic water bodies is a biological improvement method which is attracting increasing attention.In this study,five varieties of Oryzae,Ipomoea aquatic,Zizania aquatic and Alternanthera philoxeroides were cultivated in eutrophic water with a solution culture in an attempt to find suitable plant varieties for water purification.The phosphorus content of plant tissue and the bio-logical traits of plants were analysed to study the effect of phosphorus removal.The results showed that all plants grew well in eutrophic water without the addition of further nutrients.The aquatic plants removed both total phosphorus(TP)and total dissolved phosphorus(DTP).The treatments with aquatic plants removed 53.28%~84.07% of TP and 44.99%~88.81% of DTP.Treatments without aquatic plants had TP and DTP removal of 32.57% and 37.51%,respectively.Thus,bioaccumulation of phosphorus by the plants accounted for 21.54%~75.32% of total phosphorus removal,suggested that biological uptake was the main removal mechanism of phosphorus.The highest economic yield(616.28 g.m-2)was obtained with rice variety Function No.1,whose uptake accounted for 75.32% of TP removal of the system.The behaviour of Function 1 indicated a potentially positive multifunctional use(i.e.both purification of eutrophic water and high economic yield).