Experimental Research on the Purification of Urban Surface Water

In order to build purification cell for the restoration of surface water, polyester nonwovens was chosen as biofilm carriers combined with floating plant (Eichhornia crassipes) and submerge plant (Egeria densa). The water turbidity and concentration of COD, NH3-N, TN and TP were analyzed during 25d. Results demonstrated that Eichhornia crassipes has a better purifying effect than Egeria densa. Both of Eichhornia crassipes and Egeria densa with coverage of 60% can increase water transparency faster and show higher organic removal rate than the cells with coverage of 30%. But effect of plant biomass on nitrogen and phosphorus removal rate was not significant. Nonwoven-plants combination cell is better than a single non-woven or single aquatic plants system on purification result. The range analysis indicates that the existence of carriers is beneficial to the remove of COD and TP, while the type of pants is important to turbidity and NH3-N.