Research on Purification Efficiency of Plants Removal From Constructed Wetland in the Domestic Sewage

Four kinds of wetland plants,including Iris pseudacorus,Acorus calamus,Zizania aquatica and Phragmites australis were selected to study the removal efficiencies of total nitrogen(TN),total phosphorus(TP),ammonia nitrogen(NH4+-N),nitrate nitrogen(NO2--N),biological oxygen consumption(BOD5)and chemical oxygen consumption(CODCr)in domestic sewage by the vertical flow wetland.The results showed that the purification efficiency of four kinds of wetland plants were different which showed that Iris pseudacorusAcorus calamusPhragmites australisZizania aquatica.The purification efficiency to BOD5,CODCr,TP and TN of four kinds of wetland plants were higher than the NH4+-N and NO2--N purification efficiency,and the purification efficiency to all these index of Iris pseudacorus,Acorus calamus and Phragmites australis were higher than Zizania aquatica.Total biomass of different plants were from555.7g/m2 to 1 899.1g/m2.Ratios of most plant biomass aboveground(A/U)varied between 1and 2,except for Iris pseudacorus(0.66).The concentrations of nitrogen and phosphorus of aboveground biomass was hinger than belowground biomass,while the average plant accumulations of nitrogen and phosphorus were 11.38g/m2 and0.98g/m2,which the aboveground accounted for 61.31% and 73.13%.Correlation analysis showed that plant accumulations of nitrogen and phosphorus displayed significantly positive linear correlation with plant biomass and concentrations of nitrogen and phosphorus(P0.05),and biomass could be used as an indicators to screening appropriate artificial wetland plants.