In order to investigate floating macrophyte role on the purification of eutrophicated sight water named Hua-jia-chi and select appropriate native vegetable for phytoremediation

five floating macrophytes(Eichhornia crassipes

Jussiaen repens L.

Alternanthera philoxeroides(Mart.)Griseb.

Hydrocharis dubia(Bl.)Backer.and Trapa quadrispinosa Roxb.) were grown in treated water and as a none-plant to compare effectiveness of nutrient removal.It can concluded that all the floating macrophytes had a good performance on removal nutrients from treated water rather than without macrophyte and had better growth

higher application value with good foreground in sewage purification.After growing the five floating macrophytes 100 days for total nitrogen(TN) removal

Jussiaen repens L.(63%) > Eichhornia crassipes(57%) > Hydrocharis dubia(Bl.)Backer.(46%)> Trapa quadrispinosa Roxb.(42%) > Alternanthera philoxeroides(Mart.)Griseb.(34%).For total phosphorus(TP) removal

Eichhornia crassipes(52%) >Jussiaen repens L.(50%) > Hydrocharis dubia(Bl.)Backer.(45%) > Trapa quadrispinosa Roxb.(31%) > Alternanthera philoxeroides(Mart.)Griseb.(22%).The treatment enclosures with Eichhornia crassipes and Jussiaen repens L.had the best effect on sewage purification and nutrients removal.It may related to their ability of absorption and assimilation nitrogen and phosphorus from sewage as well as the action of microorganism around root.The transparence in growing Eichhornia crassipes and Jussiaen repens L.enclosures improved faster than others.It could immediately preponderate over 1.0 m after 40 days

whereas the other floating macrophytes treatment enclosures could preponderate over 1.0 m at least after 60 days.Thus it could be seen that floating macrophyte have good application foreground on the purification of eutrophicated sight water.