Purification of Stream Flowing Into Dian Lake by Ecological Floating-Bed System

The aim of the study was to examine the nutrient removal efficiency by floating-bed system grown aquatic plants and filled with spherical elastic porous stuffing materials for improving water quality of the streams flowing into Dian lake. The floating-bed system consisted of two aquatic-plant units and three groups of elastic-stuffing units. The results showed that the whole ecological floating-bed system had good performance to purify the wastewater by plant nutrient uptake, nitrification activity of root-associated and bio-membrane bacteria, filtration and sedimentation. The concentration of COD_Cr, NH₄ ⁺-N decreased 65.4%, 52.5% in routine aeration condition respectively and the numbers were 46.8%, 17.51% in low intensity aeration condition. The removal of COD_Cr, NH₄ ⁺-N, TN and TP in routine aeration condition floating-bed system were better than those in the low intensity aeration condition system and had significant difference. There was high nitrate concentration accumulation in both two kinds of intensity aeration conditions. The higher nitrate and orthophosphates removal in the floating-bed system have to be depended on aquatic plant uptake. Further research will be done to identify the nutrient uptake by large amount of aquatic plants in the whole system.