Purification effect of improved ecological floating bed on the Caohai of Dianchi Lake catchment

As a major part of the Dianchi Lake, the Caohai Lake is in a serious eutrophication situation, which is imminent for pollution treatment. An improved floating bed, which called combined packing with emergent aquatic plants canna indica, submerged aquatic plants Hydrilla verticillata and aeration device, was used to purify the water taken from the Caohai Lake. Compared with the traditional floating bed called combined packing with emergent aquatic plants canna indica and aeration device, the purification effect in the improved floating bed is obviously superior. The removal rate of CODcr, TN, TP in the improved floating bed can reach to 84%, 87.4% and 94.2%, which were 16% of CODcr, 12.2% of TN, 13% of TP higher than that in the traditional floating bed system after 25th days in motion. The result demonstrated that the Hydrilla verticality play an important role in the improved floating bed water treatment system. The improved floating bed is effective and reasonable for the purification of Caohai Lake water and it has great value in application and significant meaning in practice.