Purification of Pollutants by Ecological Floating-Bed Process for Heavily Polluted River

This paper mainly studied the characteristics of pollutants removal by ecological floating-bed for Linjiang River which was one of the heavily polluted branch rivers in Three-Gorges reservoir area. Ecological floating-bed employed ceramisite as the substrate. The removal effects of Total Nitrogen (TN), Total Phosphorus (TP) and Chemical Oxygen Demand (COD) and purification characteristics of floating-bed with two plants of canna indica and cyperus alternifolius were studied. The results showed that the plants grew well and floating-bed had good purification effects on heavily polluted water. During the spring and summer experiments, the average removal loadings of TN of canna indica and cyperus alternifolius were 1.01(g m^-2d^-1) and 0.84(g m^-2 d^-1) respectively; and those of TP were 0.179(gm^-2·d^-1) and 0.158(g m^-2·d^-1) respectively. During the autumn and winter experiments, the average removal loadings of the plants for TN and TP decreased to some extent. The canna indica floating-bed system had a good adaptability to heavily polluted river relatively under the experimental conditions. Absorption of plants was one of the important ways to remove nitrogen and phosphorus in the floating-bed system from the water. The contribution of absorption rate of the stems and leaves were higher than the roots of the plants in the floating-bed system.