Abstract: Nine aquatic plant species commonly found in northern China were transplanted in a horizontal subsurface flow constructed wetland in Beijing region to study their growth vitality in the wetland and their removal ability to the pollutants in domestic sewage. The results showed that the wetland’s front unit had greater contribution to the COD, TN and TP removal than the rear ones, and all test plant species could grow well in the wetland. After growing for 112 days, different plant species had significant differences in their N and P contents and total biomass (P<0.05). For most species, the N and P contents were higher in underground than in aboveground part, and the biomass ratio of under/aboveground part (U/A) was close to or exceeded 1. The accumulated N and P in the plants ranged from 1.36 to 7.89 g·m^-2 and from 0.19 to 1.07 g·m^-2, respectively, and the N and P accumulation in plants were more affected by plant biomass than by its N and P contents. Among the test plant species, Iris pseudacorus ranked the first in setting up the constructed wetland, followed by Typha angustifolia, Acorus calamus, and Triarrhena sacchariflora, whereasAlisma plantago aquatica and Arundo donax were not recommended due to their sensitivity in cold winter in northern China.

Key words: extended exergy analysis, driving mechanism, circulation path, eco-efficiency