浮床植物多样性及组合影响生活污水的净化效果

Ecological floating bed system has been the hotspot of research and application in the comprehensive management of polluted water environment. In order to analyze the effects of its plant diversity and composition on purification of domestic sewage, this study established five species richness levels and two composition arrangements by using Arundo donax as dominant and constructive species, and measured the plant growth, system productivity and N, P, COD removal. The results indicated that the individual biomass and relative growth rate (RGR) of wetland plants (such as A. donax) decreased with increasing species richness, while the survival and growth of mesophytes were promoted. Higher species richness decreased the productivity of the system, but increased significantly the removal of N, P and COD. At the same level of species richness, the composition with more mesophytes had lower system productivity than that with more wetland plant species, but the former had higher N, P and COD removal. Under the same species richness and composition, P removal was highest, N removal was followed, and COD removal was lowest.