Purifying urban river waters with floating bed systems

摘要

The remediation effects of a real urban river water body was studied using four floating bed systems, in which Caldesia parnassifolias, Sagittaria sagittifolia, Cyperus alternifolius, Ipomoea aquatica Forsk. were planted. A compared system without plant was also carried out. The results showed that all the 4 planted floating systems had obvious removal rates of TN and TP. After 7 days, both the TN and TP were removed speedily in the C. parnassifolias system and their levels were below "environmental surface water quality standards" class II, for which the concentration of TN and TP were 0.5 mg/L and 0.1 mg/L respectively. However, concentrations of TN and TP changed little in control. Further, TN and TP contents in the plants increase gradually, while TN and TP in the water reducing, because the nitrogen and phosphorus were necessary elements for plant growth. This research showed that building floating bed systems to purify water was effective. Since the effect of C. parnassifolias was significant and C. alternifolius has remarkable low temperature adaptability, they were more fitting for building the floating bed systems for urban river remediation.